DAC34H84_14_技术文档

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

Quad-Channel, 16-Bit, 1.25 GSPS Digital-to-Analog Converter (DAC)

Check for Samples: DAC34H84

1

FEATURES

DESCRIPTION

The DAC34H84 is a very low power, high dynamic

range, quad-channel, 16-bit digital-to-analog

converter (DAC) with a sample rate as high as 1.25

GSPS.

•

Very Low Power: 1.4 W at 1.25 GSPS

Multi-DAC Synchronization

Selectable 2x, 4x, 8x, 16x Interpolation Filter

–

Stop-Band Attenuation > 90 dBc

The device includes features that simplify the design

of complex transmit architectures: 2x to 16x digital

interpolation filters with over 90 dB of stop-band

attenuation simplify the data interface and

reconstruction filters. Independent complex mixers

allow flexible carrier placement. A high-performance

low jitter clock multiplier simplifies clocking of the

device without significant impact on the dynamic

range. The digital Quadrature Modulator Correction

(QMC) enables complete IQ compensation for gain,

offset, phase and group delay between channels in

direct up-conversion applications.

•

Flexible On-chip Complex Mixing

–

Two Independent Fine Mixers with 32-bit

NCOs

Power Saving Coarse Mixers: ± n×Fs/8

•

High Performance, Low Jitter Clock

Multiplying PLL

Digital I and Q Correction

–

Gain, Phase, Offset, and Group Delay

Correction

•

Digital Inverse Sinc Filters

32-Bit DDR Flexible LVDS Input Data Bus

Digital data is input to the device through a 32-bit

wide LVDS data bus with on-chip termination. The

wide bus allows the processing of very high

bandwidth signals. The device includes a FIFO, data

pattern checker and parity test to ease the input

–

8 Sample Input FIFO

Supports Data Rates up to 625 MSPS

Data Pattern Checker

Parity Check

interface.

The

interface

also

allows

full

•

Temperature Sensor

Differential Scalable Output: 10mA to 30mA

196-Ball, 12x12mm BGA (GREEN / Pb-Free)

synchronization of multiple devices.

The device is characterized for operation over the

entire industrial temperature range of –40°C to 85°C

and is available in a 196-ball, 12x12mm, 0.8mm pitch

BGA package.

APPLICATIONS

•

Cellular Base Stations

Diversity Transmit

Wideband Communications

The DAC34H84 very low power, high bandwidth

support, superior crosstalk, high dynamic range and

features are an ideal fit for next generation

communication systems.

spacing

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas

Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

PINOUT

ZAY Package

(Top View)

A

B

C

D

E

F

G

H

J

K

L

M

N

P

IOUT

AP

IOUT

AN

IOUT

BN

IOUT

BP

IOUT

CP

IOUT

CN

IOUT

DN

IOUT

DP

14

13

12

11

10

9

GND

DAC

CLKP

CLK

VDD

CLK

VDD

IO

VDD2

LPF

PLL

GND EXTIO BIASJ

GND ALARM SDO

DAC

CLKN

PLL

AVDD AVDD

TEST

MODE

AVDD AVDD AVDD AVDD AVDD AVDD

GND SLEEP SDIO

RESET

DAC

VDD

DAC

VDD

DAC

VDD

DAC

VDD

DAC

VDD

DAC

VDD

GND

AVDD

GND

SDENB

B

OSTR OSTR

N

DAC

VDD

DAC

VDD

DAC

VDD

DAC

VDD

GND

GND TXENA SCLK

P

SYNC SYNC

P

PARITY PARITY

GND

8

GND

N

CDP

CDN

DAB

15P

DAB

15N

DIG

VDD

DIG

VDD

DCD

0P

DCD

0N

7

GND VFUSE

VFUSE GND

DAB

14P

DAB

14N

IO

GND

DIG

VDD

DIG

VDD

IO

DCD

1P

DCD

1N

6

GND

VDD

DAB

13P

DAB

13N

IO

GND

DIG

VDD

DIG

VDD

IO

VDD

IO

VDD

DIG

VDD

DIG

VDD

IO

DCD

2P

DCD

2N

5

GND

VDD

DAB

12P

DAB

12N

DAB

8P

DAB

6P

DAB

4P

DAB

2P

DAB

0P

DCD

15P

DCD

14P

DCD

12P

DCD

10P

DCD

8P

DCD

3P

DCD

3N

4

DAB

11P

DAB

11N

DAB

8N

DAB

6N

DAB

4N

DAB

2N

DAB

0N

DCD

15N

DCD

14N

DCD

12N

DCD

10N

DCD

8N

DCD

4P

DCD

4N

3

ISTR/

PARITY

ABP

DAB

10P

DAB

10N

DAB

7P

DAB

5P

DAB

3P

DAB

1P

DATA

CLKP

DCD

13P

DCD

11P

DCD

9P

DCD

7P

DCD

5P

DCD

5N

2

ISTR/

PARITY

ABN

DAB

9P

DAB

9N

DAB

7N

DAB

5N

DAB

3N

DAB

1N

DATA

CLKN

DCD

13N

DCD

11N

DCD

9N

DCD

7N

DCD

6P

DCD

6N

1

DAC Output

Clock Input

Data Input

3.3V Supply

1.2V Supply

(except for IOVDD2)

CMOS Pins

Miscellaneous

Sync/Parity Input

Ground

P0134-01

3

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

PIN FUNCTIONS

I/O

DESCRIPTION

NAME

NO.

D10, E11,

F11, G11,

H11, J11,

K11, L10

AVDD

I

Analog supply voltage. (3.3 V)

CMOS output for ALARM condition. The ALARM output functionality is defined through the config7

register. Default polarity is active low, but can be changed to active high via config0 alarm_out_pol

control bit.

ALARM

N12

O

Full-scale output current bias. For 30mA full-scale output current, connect 1.28kΩ to ground. Change

the full-scale output current through coarse_dac(3:0) in config3, bit<15:12>

BIASJ

H12

O

I

Internal clock buffer supply voltage. (1.2 V). It is recommended to isolate this supply from DIGVDD

and DACVDD.

CLKVDD

C12, K12

LVDS positive input data bits 0 through 15 for the AB-channel path. Internal 100 Ω termination

resistor. Data format relative to DATACLKP/N clock is Double Data Rate (DDR).

A7, A6, A5,

A4, A3, A2,

A1, C4, C2,

D4, D2, E4,

E2, F4, F2,

G4

DAB15P is most significant data bit (MSB)

DAB0P is least significant data bit (LSB)

DAB[15..0]P

DAB[15..0]N

DCD[15..0]P

DCD[15..0]N

I

The order of the bus can be reversed via config2 revbus bit.

B7, B6, B5,

B4, B3, B2,

B1, C3, C1,

D3, D1, E3,

E1, F3, F1,

G3

LVDS negative input data bits 0 through 15 for the AB-channel path. (See DAB[15:0]P description

above)

H4, J4, J2,

K4, K2, L4,

L2, M4, M2,

N1, N2, N3,

N4, N5, N6,

N7

LVDS positive input data bits 0 through 15 for the CD-channel path. Internal 100 Ω termination

resistor. Data format relative to DATACLKP/N clock is Double Data Rate (DDR).

DCD15P is most significant data bit (MSB)

DCD0P is least significant data bit (LSB)

The order of the bus can be reversed via config2 revbus bit.

H3, J3, J1,

K3, K1, L3,

L1, M3, M1,

P1, P2, P3,

P4, P5, P6,

P7

LVDS negative input data bits 0 through 15 for the CD-channel path. (See DCD[15:0]P description

above)

DACCLKP

DACCLKN

A12

A11

I

Positive external LVPECL clock input for DAC core with a self-bias.

Complementary external LVPECL clock input for DAC core. (see the DACCLKP description)

D9, E9, E10,

F10, G10,

H10, J10,

DAC core supply voltage. (1.2 V). It is recommended to isolate this supply from CLKVDD and

DIGVDD.

DACVDD

I

K10, K9, L9

LVDS positive input data clock. Internal 100 Ω termination resistor. Input data DAB[15:0]P/N and

DCD[15:0]P/N are latched on both edges of DATACLKP/N (Double Data Rate).

DATACLKP

DATACLKN

G2

G1

I

LVDS negative input data clock. (See DATACLKP description)

E5, E6, E7,

F5, J5, K5,

K6, K7

DIGVDD

EXTIO

I

Digital supply voltage. (1.2 V). It is recommended to isolate this supply from CLKVDD and DACVDD.

Used as external reference input when internal reference is disabled through config27 extref_ena =

G12

I/O ‘1’. Used as internal reference output when config27 extref_ena = ‘0’ (default). Requires a 0.1 μF

decoupling capacitor to AGND when used as reference output.

LVDS input strobe positive input. Internal 100 Ω termination resistor.

The main functions of this input are to sync the FIFO pointer, to provide a sync source to the digital

blocks, and/or to act as a parity input for the AB-data bus.

These functions are captured with the rising edge of DATACLKP/N. This signal should be

edge-aligned with DAB[15:0]P/N and DCD[15:0]P/N.

The PARITY, SYNC, and ISTR inputs are rotated to allow complete reversal of the data interface

when setting the rev_interface bit in register config1.

ISTRP/

PARITYABP

H2

H1

I

ISTRN/

PARITYABN

LVDS input strope negative input. (See the ISTRP/PARITYABP description)

4

DAC34H84

www.ti.com

NAME

SLAS751A –MARCH 2011–REVISED JUNE 2011

PIN FUNCTIONS (continued)

I/O

DESCRIPTION

NO.

A10, A13,

A14, B10,

B11, B12,

B13, C5, C6,

C7, C8, C9,

C10, C13,

D8, D13,

D14, E8,

E12, E13,

F6, F7, F8,

F9, F12, F13,

G6, G7, G8,

G9, G13,

GND

I

These pins are ground for all supplies.

G14, H6, H7,

H8, H9, H13,

H14, J6, J7,

J8, J9, J12,

J13, K8, K13,

L8, L13, L14,

M5, M6, M7,

M8, M9,

M10, M11,

M12, M13,

N13, P13,

P14

IOUTAP

IOUTAN

IOUTBP

IOUTBN

IOUTCP

IOUTCN

IOUTDP

IOUTDN

B14

C14

F14

E14

J14

O

A-Channel DAC current output. Connect directly to ground if unused.

A-Channel DAC complementary current output. Connect directly to ground if unused.

B-Channel DAC current output. Connect directly to ground if unused.

B-Channel DAC complementary current output. Connect directly to ground if unused.

C-Channel DAC current output. Connect directly to ground if unused.

K14

N14

M14

C-Channel DAC complementary current output. Connect directly to ground if unused.

D-Channel DAC current output. Connect directly to ground if unused.

D-Channel DAC complementary current output. Connect directly to ground if unused.

D5, D6, G5,

H5, L5. L6

IOVDD

I

Supply voltage for all LVDS I/O. (3.3 V)

Supply voltage for all CMOS I/O. (1.8 to 3.3V) This supply can range from 1.8V to 3.3V to change the

input and output level of the CMOS I/O.

IOVDD2

LPF

L12

D12

I/O PLL loop filter connection. If not using the clock multiplying PLL, the LPF pin can be left unconnected.

Optional LVPECL output strobe positive input. This positive/negative pair is captured with the rising

OSTRP

OSTRN

A9

B9

I

edge of DACCLKP/N. It is used to sync the divided-down clocks and FIFO output pointer in Dual Sync

Sources Mode. If unused it can be left unconnected.

I

Optional LVPECL output strobe negative input. (See the OSTRP description)

Optional LVDS positive input parity bit for the CD-data bus. The PARITYCDP/N LVDS pair has an

internal 100 Ω termination resistor. If unused it can be left unconnected.

The PARITY, SYNC, and ISTR inputs are rotated to allow complete reversal of the data interface

when setting the rev_interface bit in register config1.

PARITYCDP N8

PARITYCDN P8

I

Optional LVDS negative input parity bit for the CD-data bus.

PLL analog supply voltage. (3.3 V)

PLLAVDD

SCLK

C11, D11

P9

Serial interface clock. Internal pull-down.

SDENB

P10

Active low serial data enable, always an input to the DAC34H84. Internal pull-up.

Serial interface data. Bi-directional in 3-pin mode (default) and uni-directional 4-pin mode. Internal

pull-down.

SDIO

P11

1/O

Uni-directional serial interface data in 4-pin mode. The SDO pin is tri-stated in 3-pin interface mode

(default).

SDO

P12

N11

O

I

SLEEP

Active high asynchronous hardware power-down input. Internal pull-down.

5

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

PIN FUNCTIONS (continued)

I/O

DESCRIPTION

NAME

NO.

LVDS SYNC positive input. Internal 100 Ω termination resistor. If unused it can be left unconnected.

The PARITY, SYNC, and ISTR inputs are rotated to allow complete reversal of the data interface

when setting the rev_interface bit in register config1.

SYNCP

A8

I

SYNCN

B8

I

LVDS SYNC negative input.

RESETB

N10

Active low input for chip RESET. Internal pull-up.

Transmit enable active high input. Internal pull-down.

To enable analog output data transmission, set sif_txenable in register config3 to “1” or pull CMOS

TXENA

N9

I

TXENA pin to high.

To disable analog output, set sif_txenable to “0” and pull CMOS TXENA pin to low. The DAC output

is forced to midscale.

TESTMODE L11

VFUSE D7, L7

I

This pin is used for factory testing. Internal pull-down. Leave unconnected for normal operation.

Digital supply voltage. This supply pin is also used for factory fuse programming. Connect to

DACVDD or DIGVDD for normal operation.

ORDERING INFORMATION⁽¹⁾

T_A

–40°C to 85°C

ORDER CODE

DAC34H84IZAY

DAC34H84IZAYR

PACKAGE DRAWING/TYPE⁽²⁾

TRANSPORT MEDIA

Tray

QUANTITY

160

ZAY / 196 NFBGA

Tape and Reel

1000

(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or visit the

device product folder at www.ti.com.

(2) MSL Peak Temperature: Level-3-260C-168 HR

ABSOLUTE MAXIMUM RATINGS

over operating free-air temperature range (unless otherwise noted)⁽¹⁾

VALUE

UNIT

MIN

–0.5

MAX

1.5

4

DACVDD, DIGVDD, CLKVDD

VFUSE

V

Supply voltage

range⁽²⁾

IOVDD, IOVDD2

AVDD, PLLAVDD

4

DAB[15..0]P/N, DCD[15..0]P/N, DATACLKP/N, ISTRP/N, PARITYCDP/N,

SYNCP/N

–0.5

IOVDD + 0.5

CLKVDD + 0.5

IOVDD2 + 0.5

V

DACCLKP/N, OSTRP/N

ALARM, SDO, SDIO, SCLK, SDENB, SLEEP, RESETB, TESTMODE,

TXENA

Pin voltage range⁽²⁾

IOUTAP/N, IOUTBP/N, IOUTCP/N, IOUTDP/N

–1.0

–0.5

AVDD + 0.5

V

EXTIO, BIASJ

LPF

AVDD + 0.5

PLLAVDD + 0.5

V

Peak input current (any input)

20

–30

85

mA

°C

Peak total input current (all inputs)

Operating free-air temperature range, T_A: DAC34H84

Storage temperature range

–40

–65

150

(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings

only and functional operation of these or any other conditions beyond those indicated under “recommended operating conditions” is not

implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

(2) Measured with respect to GND.

6

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

THERMAL INFORMATION

DAC34H84

THERMAL METRIC⁽¹⁾

BGA

UNITS

(196 ball) PINS

T_J

Maximum junction temperature

125

37.6

6.8

°C

θ_JA

Junction-to-ambient thermal resistance⁽²⁾

Junction-to-case (top) thermal resistance⁽³⁾

Junction-to-case (bottom) thermal resistance⁽⁴⁾

Junction-to-board thermal resistance⁽⁵⁾

Junction-to-top characterization parameter⁽⁶⁾

Junction-to-board characterization parameter⁽⁷⁾

θ_JCtop

θ_JCbot

θ_JB

N/A

16.8

0.2

°C/W

ψ_JT

ψ_JB

16.4

(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

(2) The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, high-K board, as

specified in JESD51-7, in an environment described in JESD51-2a.

(3) The junction-to-case (top) thermal resistance is obtained by simulating a cold plate test on the package top. No specific

JEDEC-standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.

(4) The junction-to-case (bottom) thermal resistance is obtained by simulating a cold plate test on the exposed (power) pad. No specific

JEDEC standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.

(5) The junction-to-board thermal resistance is obtained by simulating in an environment with a ring cold plate fixture to control the PCB

temperature, as described in JESD51-8.

(6) The junction-to-top characterization parameter, ψ_JT, estimates the junction temperature of a device in a real system and is extracted

from the simulation data for obtaining θ_JA, using a procedure described in JESD51-2a (sections 6 and 7).

(7) The junction-to-board characterization parameter, ψ_JB, estimates the junction temperature of a device in a real system and is extracted

from the simulation data for obtaining θ_JA, using a procedure described in JESD51-2a (sections 6 and 7).

7

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

ELECTRICAL CHARACTERISTICS – DC SPECIFICATIONS⁽¹⁾

over recommended operating free-air temperature range, nominal supplies, IOUT_FS= 20mA (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP MAX

UNIT

Resolution

16

Bits

DC ACCURACY

DNL

INL

Differential nonlinearity

Integral nonlinearity

±2

±4

LSB

1 LSB = IOUT_FS/2¹⁶

ANALOG OUTPUT

Coarse gain linearity

±0.04

±0.001

±2

LSB

%FSR

mA

Offset error

Mid code offset

With external reference

With internal reference

Gain error

±2

Gain mismatch

±2

Full scale output current

Output compliance range

Output resistance

10

20

30

–0.5

0.6

V

300

5

kΩ

Output capacitance

pF

REFERENCE OUTPUT

V_REF

Reference output voltage

Reference output current⁽²⁾

1.2

V

100

nA

REFERENCE INPUT

V_EXTIOInput voltage range

0.6

1.2 1.25

V

External Reference Mode

Input resistance

1

472

100

MΩ

kHz

pF

Small signal bandwidth

Input capacitance

TEMPERATURE COEFFICIENTS

Offset drift

±1

±15

±30

±8

ppm/°C

with external reference

with internal reference

Gain drift

Reference voltage drift

POWER SUPPLY

AVDD, IOVDD, PLLAVDD

CLKVDD, DACVDD, DIGVDD

IOVDD2

3.14

1.14

1.71

3.3 3.46

1.2 1.26

3.3 3.45

V

PSRR

Power supply rejection ratio

DC tested

±0.25

%FSR/V

POWER CONSUMPTION

I_(AVDD)

I_(DIGVDD)

I_(DACVDD)

I_(CLKVDD)

P

Analog supply current⁽³⁾

135 165

740 820

mA

mW

mA

mW

MODE 1

Digital supply current

DAC supply current

Clock supply current

Power dissipation

Analog supply current⁽³⁾

Digital supply current

DAC supply current

Clock supply current

Power dissipation

f_DAC= 1.25GSPS, 2x interpolation, Mixer on,

QMC on, invsinc on, PLL enabled, 20mA FS

output, IF = 200MHz

40

60

100 120

1500 1750

I_(AVDD)

I_(DIGVDD)

I_(DACVDD)

I_(CLKVDD)

P

125

740

45

MODE 2

f_DAC= 1.25GSPS, 2x interpolation, Mixer on,

QMC on, invsinc on, PLL disabled, 20mA FS

output, IF = 200MHz

75

1440

(1) Measured differentially across IOUTP/N with 25 Ω each to GND.

(2) Use an external buffer amplifier with high impedance input to drive any external load.

(3) Includes AVDD, PLLAVDD, and IOVDD

8

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

ELECTRICAL CHARACTERISTICS – DC SPECIFICATIONS⁽¹⁾(continued)

over recommended operating free-air temperature range, nominal supplies, IOUT_FS= 20mA (unless otherwise noted)

PARAMETER

Analog supply current⁽³⁾

Digital supply current

DAC supply current

Clock supply current

Power dissipation

Analog supply current⁽³⁾

Digital supply current

DAC supply current

Clock supply current

Power dissipation

Analog supply current⁽³⁾

Digital supply current

DAC supply current

Clock supply current

Power dissipation

Analog supply current⁽³⁾

Digital supply current

DAC supply current

Clock supply current

Power dissipation

TEST CONDITIONS

MIN

TYP MAX

120

370

25

UNIT

mA

mW

mA

mW

mA

mW

mA

mW

mA

mW

°C

I_(AVDD)

I_(DIGVDD)

I_(DACVDD)

I_(CLKVDD)

P

MODE 3

f_DAC= 625MSPS, 2x interpolation, Mixer on,

QMC on, invsinc off, PLL disabled, 20mA FS

output, IF = 200MHz

45

925

50

I_(AVDD)

I_(DIGVDD)

I_(DACVDD)

I_(CLKVDD)

P

MODE 4

750

40

f_DAC= 1.25GSPS, 2x interpolation, Mixer on,

QMC on, invsinc on, PLL enabled, Channels

A/B/C/D output sleep, IF = 200MHz,

100

1240

40

I_(AVDD)

I_(DIGVDD)

I_(DACVDD)

I_(CLKVDD)

P

Mode 5

10

Power-Down mode: No clock, DAC on sleep

mode (clock receiver sleep),

Channels A/B/C/D output sleep, static data

pattern

5

15

150

140

360

30

I_(AVDD)

I_(DIGVDD)

I_(DACVDD)

I_(CLKVDD)

P

Mode 6

f_DAC= 1GSPS, 2x interpolation, Mixer off,

QMC off, invsinc off, PLL enabled, 20mA FS

output, IF = 200MHz

90

1040

120

370

30

I_(AVDD)

I_(DIGVDD)

I_(DACVDD)

I_(CLKVDD)

P

Analog supply current⁽³⁾

Digital supply current

DAC supply current

Clock supply current

Power dissipation

Mode 7

f_DAC= 1GSPS, 2x interpolation, Mixer off,

QMC off, invsinc off, PLL disabled, 20mA FS

output, IF = 200MHz

65

960

Operating Range

–40

25

85

9

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

ELECTRICAL CHARACTERISTICS – DIGITAL SPECIFICATIONS

over operating free-air temperature range (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX UNIT

LVDS INPUTS: DAB[15:0]P/N, DCD[15:0]P/N, DATACLKP/N, ISTRP/N, SYNCP/N, PARITYCDP/N⁽¹⁾

Logic high differential input voltage

threshold

V_A,B+

200

mV

Logic low differential input voltage

threshold

V_A,B–

–200

mV

V_COM

Z_T

Input Common Mode

Internal termination

1.0

85

1.2

110

2

1.6

V

Ω

135

C_L

LVDS Input capacitance

Interleaved LVDS data transfer rate

Input data rate

pF

f_INTERL

f_DATA

1250 MSPS

625 MSPS

CLOCK INPUT (DACCLKP/N)

Duty cycle

40%

0.4

60%

V

Differential voltage⁽²⁾

DACCLKP/N Input Frequency

OUTPUT STROBE (OSTRP/N)

1.0

1250

MHz

V

f_OSTR= f_DACCLK/ (n x 8 x Interp) where

n is any positive integer,

f_DACCLKis DACCLK frequency in MHz

f_DACCLK

/

f_OSTR

Frequency

(8 x interp)

Duty cycle

50%

1.0

Differential voltage

0.4

CMOS INTERFACE: ALARM, SDO, SDIO, SCLK, SDENB, SLEEP, RESETB, TXENA

0.7 x

IOVDD2

V_IH

V_IL

High-level input voltage

Low-level input voltage

V

0.3 x

IOVDD2

I_IH

I_IL

C_I

High-level input current

Low-level input current

CMOS Input capacitance

-40

40

µA

pF

2

IOVDD2 –

I_load= –100 μA

I_load= –2 mA

V

0.2

V_OH

ALARM, SDO, SDIO

0.8 x

IOVDD2

I_load= 100 μA

0.2

0.5

V

V_OL

I_load= 2 mA

DIGITAL INPUT TIMING SPECIFICATIONS

Timing LVDS inputs: DAB[15:0]P/N, DCD[15:0]P/N, ISTRP/N, SYNCP/N, PARITYCDP/N, double edge latching

Setup time, DAB[15:0]P/N,

DCD[15:0]P/N, ISTRP/N, SYNCP/N, ISTRP/N and SYNCP/N reset latched

t_s(DATA)

150

ps

and PARITYCDP/N, valid to either

edge of DATACLKP/N

only on rising edge of DATACLKP/N

Hold time, DAB[15:0]P/N,

DCD[15:0]P/N, ISTRP/N, SYNCP/N ISTRP/N and SYNCP/N reset latched

and PARITYCDP/N valid after either only on rising edge of DATACLKP/N

edge of DATACLKP/N

t_h(DATA)

400

t_{(ISTR_SYNC)}

t_(align)

ISTRP/N and SYNCP/N pulse width f_DATACLKis DATACLK frequency in MHz

Maximum offset between

1/2f_DATACLK

ns

ps

DATACLKP/N and DACCLKP/N

rising edges

FIFO Bypass Mode only

±300

(1) See LVDS INPUTS section for terminology.

(2) Driving the clock input with a differential voltage lower than 1 V may result in degraded performance.

10

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

ELECTRICAL CHARACTERISTICS – DIGITAL SPECIFICATIONS (continued)

over operating free-air temperature range (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX UNIT

TIMING OUTPUT STROBE INPUT: DACCLKP/N rising edge LATCHING⁽³⁾

Setup time, OSTRP/N valid to rising

edge of DACCLKP/N

t_s(OSTR)

–100

ps

Hold time, OSTRP/N valid after

t_h(OSTR)

500

rising edge of DACCLKP/N

(4)

TIMING SYNC INPUT: DACCLKP/N rising edge LATCHING

Setup time, SYNCP/N valid to rising

t_{s(SYNC_PLL)}

200

300

ps

edge of DACCLKP/N

Hold time, SYNCP/N valid after

t_{h(SYNC_PLL)}

rising edge of DACCLKP/N

TIMING SERIAL PORT

Setup time, SDENB to rising edge

t_s(SDENB)

of SCLK

20

10

5

ns

Setup time, SDIO valid to rising

edge of SCLK

t_s(SDIO)

Hold time, SDIO valid to rising edge

of SCLK

t_h(SDIO)

Register config6 read (temperature

sensor read)

1

µs

ns

t_(SCLK)

Period of SCLK

All other registers

100

Data output delay after falling edge

of SCLK

t_d(Data)

t_RESET

10

25

Minimum RESETB pulsewidth

(3) OSTR is required in Dual Sync Sources mode. In order to minimize the skew it is recommended to use the same clock distribution

device such as Texas Instruments CDCE62005 to provide the DACCLK and OSTR signals to all the DAC34H84 devices in the system.

Swap the polarity of the DACCLK outputs with respect to the OSTR ones to establish proper phase relationship.

(4) SYNC is required to synchronize the PLL circuit in mulitple devices. The SYNC signal must meet the timing relationship with respect to

the reference clock (DACCLKP/N) of the on-chip PLL circuit.

11

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

ELECTRICAL CHARACTERISTICS – AC SPECIFICATIONS

over recommended operating free-air temperature range, nominal supplies, IOUT_FS= 20mA (unless otherwise noted)

PARAMETER

TEST CONDITIONS / COMMENTS

MIN

TYP

MAX

UNIT

ANALOG OUTPUT⁽¹⁾

f_DAC

Maximum DAC rate

1250

MSPS

ns

t_s(DAC)

Output settling time to 0.1%

Transition: Code 0x0000 to 0xFFFF

10

2

DAC outputs are updated on the falling edge of DAC

clock. Does not include Digital Latency (see below).

t_pd

Output propagation delay

ns

t_r(IOUT)

t_f(IOUT)

Output rise time 10% to 90%

Output fall time 90% to 10%

220

ps

No interpolation, FIFO on, Mixer off, QMC off, Inverse

sinc off

128

2x Interpolation

216

376

726

1427

24

4x Interpolation

DAC clock

cycles

8x Interpolation

Digital Latency

16x Interpolation

Fine Mixer

QMC

16

Inverse Sinc

20

DAC Wake-up Time from Deep Sleep

DAC Deep Sleep Time

IOUT current settling to 1% of IOUT_FS

IOUT current settling to less than 1% of IOUT_FS

90

Power-up

Time

μs

90

AC PERFORMANCE⁽²⁾

f_DAC= 1.25 GSPS, f_OUT= 20 MHz

f_DAC= 1.25 GSPS, f_OUT= 50 MHz

f_DAC= 1.25 GSPS, f_OUT= 70 MHz

f_DAC= 1.25 MSPS, f_OUT= 30 ± 0.5 MHz

f_DAC= 1.25 GSPS, f_OUT= 50 ± 0.5 MHz

f_DAC= 1.25 GSPS, f_OUT= 100 ± 0.5 MHz

f_DAC= 1.25 GSPS, f_OUT= 10 MHz

f_DAC= 1.25 GSPS, f_OUT= 80 MHz

f_DAC= 1.2288 GSPS, f_OUT= 30.72 MHz

f_DAC= 1.2288 GSPS, f_OUT= 153.6 MHz

f_DAC= 1.2288 GSPS, f_OUT= 30.72 MHz

f_DAC= 1.2288 GSPS, f_OUT= 153.6 MHz

f_DAC= 1.25 GSPS, f_OUT= 10 MHz

73

70

Spurious free dynamic range

(0 to f_DAC/2) Tone at 0 dBFS

SFDR

dBc

66

87

Third-order two-tone intermodulation

distortion

Each tone at –12 dBFS

IMD3

NSD

85

dBc

78

Noise Spectral Density⁽³⁾

Tone at 0dBFS

160

155

77

dBc/Hz

Adjacent channel leakage ratio, single

carrier

74

ACLR⁽³⁾

dBc

82

Alternate channel leakage ratio, single

carrier

80

Channel Isolation

95

(1) Measured single ended into 50 Ω load.

(2) 4:1 transformer output termination, 50 Ω doubly terminated load

(3) Single carrier, W-CDMA with 3.84 MHz BW, 5-MHz spacing, centered at IF, PAR = 12dB. TESTMODEL 1, 10 ms

12

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

TYPICAL CHARACTERISTICS

All plots are at 25°C, nominal supply voltage, f_DAC= 1250 MSPS, 2x interpolation, NCO enabled, Mixer Gain disabled, QMC

enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20 mA full-scale output current with 4:1 transformer

(unless otherwise noted)

6

5

4

3

2

1

0

−1

−2

−3

−4

−5

−6

−1

−2

−3

−4

−5

0

10k

20k

30k

Code

40k

50k

60k

0

10k

20k

30k

Code

40k

50k

60k

Figure 1. Integral Nonlinearity

Figure 2. Differential Nonlinearity

100

90

80

70

60

50

40

30

100

90

80

70

60

50

40

30

0 dBFS

−6 dBFS

−12 dBFS

0 dBFS

−6 dBFS

−12 dBFS

0

100

200

300

400

500

600

0

100

200

300

400

500

600

Output Frequency (MHz)

Figure 3. SFDR vs Output Frequency Over Input Scale

Figure 4. Second Harmonic Distortion vs Output

Frequency Over Input Scale

100

90

80

70

60

50

40

30

f_DATA= 625 MSPS, 1x Interpolation

f_DATA= 625 MSPS, 2x Interpolation

f_DATA= 312.5 MSPS, 4x Interpolation

f_DATA= 156.25MSPS, 8x Interpolation

0 dBFS

−6 dBFS

−12 dBFS

90

80

f_DATA= 78.125MSPS, 16x Interpolation

70

60

50

40

30

0

100

200

300

400

500

600

0

100

200

300

400

500

600

Output Frequency (MHz)

Figure 5. Third Harmonic Distortion vs Output Frequency

Over Input Scale

Figure 6. SFDR vs Output Frequency Over Interpolation

13

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

TYPICAL CHARACTERISTICS (continued)

All plots are at 25°C, nominal supply voltage, f_DAC= 1250 MSPS, 2x interpolation, NCO enabled, Mixer Gain disabled, QMC

enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20 mA full-scale output current with 4:1 transformer

(unless otherwise noted)

100

90

80

70

60

50

40

30

100

90

80

70

60

50

40

30

f_DAC= 600 MSPS

f_DAC= 800 MSPS

f_DAC= 1000 MSPS

f_DAC= 1250 MSPS

I_OUTFS = 10 mA w/ 4:1 Transformer

I_OUTFS = 20 mA w/ 4:1 Transformer

I_OUTFS = 30 mA w/ 2:1 Transformer

0

100

200

300

400

500

600

0

50

100

150

200

250

300

350

400

Output Frequency (MHz)

Figure 7. SFDR vs Output Frequency Over f_DAC

Figure 8. SFDR vs Output Frequency Over I_OUTFS

10

0

10

NCO Bypassed

QMC Bypassed

f_DAC= 1250 MSPS

f_OUT= 20 MHz

NCO Bypassed

QMC Bypassed

f_DAC= 1250 MSPS

f_OUT= 70 MHz

0

−10

−20

−30

−40

−50

−60

−70

−80

−90

−10

−20

−30

−40

−50

−60

−70

−80

−90

0

100

200

300

400

500

600

0

100

200

300

400

500

600

Frequency (MHz)

Figure 9. Single Tone Spectral Plot

Figure 10. Single Tone Spectral Plot

10

0

10

0

f_DAC= 1250 MSPS

f_OUT= 150 MHz

f_DAC= 1250 MSPS

f_OUT= 200 MHz

−10

−20

−30

−40

−50

−60

−70

−80

−90

−10

−20

−30

−40

−50

−60

−70

−80

−90

0

100

200

300

400

500

600

10

110

210

310

410

510

610

Frequency (MHz)

Figure 11. Single Tone Spectral Plot

Figure 12. Single Tone Spectral Plot

14

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

TYPICAL CHARACTERISTICS (continued)

All plots are at 25°C, nominal supply voltage, f_DAC= 1250 MSPS, 2x interpolation, NCO enabled, Mixer Gain disabled, QMC

enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20 mA full-scale output current with 4:1 transformer

(unless otherwise noted)

10

0

100

90

80

70

60

50

40

30

PLL Enabled w/ PFD of 78.125 MHz

f_DAC= 1250 MSPS

f_OUT= 200 MHz

0 dBFS

−6 dBFS

−12 dBFS

−10

−20

−30

−40

−50

−60

−70

−80

−90

10

110

210

310

410

510

610

0

100

200

300

400

500

600

Frequency (MHz)

Output Frequency (MHz)

Figure 13. Single Tone Spectral Plot

Figure 14. IMD3 vs Output Frequency Over Input Scale

100

90

80

70

60

50

40

30

100

f_DAC= 600 MSPS

f_DAC= 800 MSPS

f_DAC= 1000 MSPS

f_DAC= 1250 MSPS

90

80

70

60

50

40

30

f_DATA= 625 MSPS, 1x Interpolation

f_DATA= 625 MSPS, 2x Interpolation

f_DATA= 312.5 MSPS, 4x Interpolation

f_DATA= 156.25 MSPS, 8x Interpolation

f_DATA= 78.125 MSPS, 16x Interpolation

0

100

200

300

400

500

600

0

100

200

300

400

500

600

Output Frequency (MHz)

Figure 15. IMD3 vs Output Frequency Over Interpolation

Figure 16. IMD3 vs Output Frequency Over f_DAC

100

90

80

70

60

0

−10

−20

−30

−40

−50

−60

−70

−80

−90

−100

NCO Bypassed

QMC Bypassed

f_DAC= 1250 MSPS

f_OUT= 70 MHz

Tone Spacing = 1 MHz

50

I_OUTFS = 10 mA w/ 4:1 Transformer

I_OUTFS = 20 mA w/ 4:1 Transformer

I_OUTFS = 30 mA w/ 2:1 Transformer

40

30

0

50

100

150

200

250

300

350

400

65

66

67

68

69

70

71

72

73

74

75

Output Frequency (MHz)

Frequency (MHz)

Figure 17. IMD3 vs Output Frequency Over I_OUTFS

Figure 18. Two Tone Spectral Plot

15

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

TYPICAL CHARACTERISTICS (continued)

All plots are at 25°C, nominal supply voltage, f_DAC= 1250 MSPS, 2x interpolation, NCO enabled, Mixer Gain disabled, QMC

enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20 mA full-scale output current with 4:1 transformer

(unless otherwise noted)

0

−10

−20

−30

−40

−50

−60

−70

−80

−90

−100

170

165

160

155

150

145

140

135

130

f_DAC= 1250 MSPS

f_OUT= 200 MHz

Tone Spacing = 1 MHz

0 dBFS

−6 dBFS

−12 dBFS

195 196 197 198 199 200 201 202 203 204 205

Frequency (MHz)

0

100

200

300

400

500

600

Output Frequency (MHz)

Figure 19. Two Tone Spectral Plot

Figure 20. NSD vs Output Frequency Over Input Scale

170

f_DATA= 625 MSPS, 1x Interpolation

f_DATA= 625 MSPS, 2x Interpolation

f_DATA= 312.5 MSPS, 4x Interpolation

f_DATA= 156.25 MSPS, 8x Interpolation

f_DATA= 78.125 MSPS, 16x Interpolation

f_DAC= 600 MSPS

f_DAC= 800 MSPS

f_DAC= 1000 MSPS

f_DAC= 1250 MSPS

165

160

155

150

145

140

135

130

165

160

155

150

145

140

135

130

0

100

200

300

400

500

600

0

100

200

300

400

500

600

Output Frequency (MHz)

Figure 21. NSD vs Output Frequency Over Interpolation

Figure 22. NSD vs Output Frequency Over f_DAC

170

165

160

155

150

145

140

135

130

I_OUTFS = 10 mA w/ 4:1 Transformer

I_OUTFS = 20 mA w/ 4:1 Transformer

I_OUTFS = 30 mA w/ 2:1 Transformer

PLL Bypassed

PLL Enabled w/ PFD of 78.125 MHz

165

160

155

150

145

140

135

130

0

50

100

150

200

250

300

350

400

0

100

200

300

400

500

600

Output Frequency (MHz)

Figure 23. NSD vs Output Frequency Over I_OUTFS

Figure 24. NSD vs Output Frequency Over Clocking

Options

16

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

TYPICAL CHARACTERISTICS (continued)

All plots are at 25°C, nominal supply voltage, f_DAC= 1250 MSPS, 2x interpolation, NCO enabled, Mixer Gain disabled, QMC

enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20 mA full-scale output current with 4:1 transformer

(unless otherwise noted)

85

80

75

70

65

60

55

85

80

75

70

65

60

55

PLL Disabled

PLL Enabled

PLL Disabled

PLL Enabled

0

100

200

300

400

500

600

0

100

200

300

400

500

600

Output Frequency (MHz)

Figure 25. Single Carrier WCDMA ACLR (Adjacent) vs

Output Frequency Over Clocking Options

Figure 26. Single Carrier WCDMA ACLR (Alternate) vs

Output Frequency Over Clocking Options

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

f_OUT= 70 MHz

f_OUT= 120 MHz

Figure 27. Single Carrier W-CDMA Test Model 1

Figure 28. Single Carrier W-CDMA Test Model 1

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

f_OUT= 70 MHz

f_OUT= 200 MHz

Figure 29. Single Carrier W-CDMA Test Model 1

Figure 30. Four Carrier W-CDMA Test Model 1

17

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

TYPICAL CHARACTERISTICS (continued)

All plots are at 25°C, nominal supply voltage, f_DAC= 1250 MSPS, 2x interpolation, NCO enabled, Mixer Gain disabled, QMC

enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20 mA full-scale output current with 4:1 transformer

(unless otherwise noted)

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

f_OUT= 200 MHz

f_OUT= 120 MHz

Figure 31. Four Carrier W-CDMA Test Model 1

Figure 32. Four Carrier W-CDMA Test Model 1

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

f_OUT= 140 MHz

f_OUT= 240 MHz

Figure 33. 10 MHz Single Carrier LTE Test Model 3.1

Figure 34. 10 MHz Single Carrier LTE Test Model 3.1

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

2x Interpolation, 0 dBFS

f_DAC= 1228.8 MSPS

f_OUT= 140 MHz

f_OUT= 240 MHz

Figure 35. 20 MHz Single Carrier LTE Test Model 3.1

Figure 36. 20 MHz Single Carrier LTE Test Model 3.1

18

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

TYPICAL CHARACTERISTICS (continued)

All plots are at 25°C, nominal supply voltage, f_DAC= 1250 MSPS, 2x interpolation, NCO enabled, Mixer Gain disabled, QMC

enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20 mA full-scale output current with 4:1 transformer

(unless otherwise noted)

1400

1200

1000

800

1400

1200

1000

800

1x Interpolation

2x Interpolation

4x Interpolation

8x Interpolation

16x Interpolation

1x Interpolation

2x Interpolation

4x Interpolation

8x Interpolation

16x Interpolation

600

Bandbase Input = 5 MHz

NCO Disabled

QMC Disabled

Bandbase Input = 0 MHz

NCO Enabled w/ 5 MHz Mixing

QMC Enabled

400

CMIX Disabled

200

0

200

400

600

800

1000

1200

0

200

400

600

800

1000

1200

f_DAC(MSPS)

Figure 37. Power Consumption vs f_DACOver Interpolation

Figure 38. Power Consumption vs f_DACOver Interpolation

160

700

NCO Enabled

QMC Enabled

1x Interpolation

2x Interpolation

4x Interpolation

8x Interpolation

16x Interpolation

Bandbase Input = 5 MHz

NCO Disabled

QMC Disabled

140

120

100

80

600

500

400

300

200

100

0

CMIX Disabled

60

40

20

0

200

400

600

800

1000

1200

0

200

400

600

800

1000

1200

f_DAC(MSPS)

Figure 39. Power Consumption vs f_DACOver Digital

Processing Functions

Figure 40. DIGVDD Current vs f_DACOver Interpolation

700

160

1x Interpolation

2x Interpolation

4x Interpolation

8x Interpolation

16x Interpolation

NCO Enabled

QMC Enabled

140

120

100

80

600

500

400

300

200

100

0

60

40

Bandbase Input = 0 MHz

NCO Enabled w/ 5 MHz Mixing

QMC Enabled

20

0

200

400

600

800

1000

1200

0

200

400

600

800

1000

1200

f_DAC(MSPS)

Figure 41. DIGVDD Current vs f_DACOver Interpolation

Figure 42. DIGVDD Current vs f_DACOver Digital

Processing Functions

19

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

TYPICAL CHARACTERISTICS (continued)

All plots are at 25°C, nominal supply voltage, f_DAC= 1250 MSPS, 2x interpolation, NCO enabled, Mixer Gain disabled, QMC

enabled with gain set at 1446 for both I/Q channels, 0 dBFS digital input, 20 mA full-scale output current with 4:1 transformer

(unless otherwise noted)

40

35

30

25

20

15

10

5

100

90

80

70

60

50

40

30

20

10

0

200

400

600

800

1000

1200

0

200

400

600

800

1000

1200

f_DAC(MSPS)

Figure 43. DACVDD Current vs f_DAC

Figure 44. CLKVDD Current vs f_DAC

140

120

100

80

120

110

100

90

Channel A

Channel B

80

60

70

40

60

20

50

Channel A/B Off

Channel C/D Active

0

40

200

400

600

800

1000

1200

0

100

200

300

400

500

600

Output Frequency (MHz)

f_DAC(MSPS)

Figure 45. AVDD Current vs f_DAC

Figure 46. Channel Isolation vs Output Frequency

120

110

100

90

110

Channel C

Channel D

Channel A

Channel B

Channel C

Channel D

100

90

80

70

60

50

40

30

20

10

0

80

70

60

f_DAC= 614.4 MSPS

f_OUT= 138.4 MHz

50

Channel C/D Off

Channel A/B Active

40

100 200

300

400

500

600

0

32

64

96

128

160

192

224

256

Output Frequency (MHz)

Step Code

Figure 47. Channel Isolation vs Output Frequency

Figure 48. Group Delay vs Step Code

20

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

DEFINITION OF SPECIFICATIONS

Adjacent Carrier Leakage Ratio (ACLR): Defined for a 3.84Mcps 3GPP W-CDMA input signal measured in a

3.84MHz bandwidth at a 5MHz offset from the carrier with a 12dB peak-to-average ratio.

Analog and Digital Power Supply Rejection Ratio (APSSR, DPSSR): Defined as the percentage error in the

ratio of the delta IOUT and delta supply voltage normalized with respect to the ideal IOUT current.

Differential Nonlinearity (DNL): Defined as the variation in analog output associated with an ideal 1 LSB

change in the digital input code.

Gain Drift: Defined as the maximum change in gain, in terms of ppm of full-scale range (FSR) per °C, from the

value at ambient (25°C) to values over the full operating temperature range.

Gain Error: Defined as the percentage error (in FSR%) for the ratio between the measured full-scale output

current and the ideal full-scale output current.

Integral Nonlinearity (INL): Defined as the maximum deviation of the actual analog output from the ideal output,

determined by a straight line drawn from zero scale to full scale.

Intermodulation Distortion (IMD3): The two-tone IMD3 is defined as the ratio (in dBc) of the 3rd-order

intermodulation distortion product to either fundamental output tone.

Offset Drift: Defined as the maximum change in DC offset, in terms of ppm of full-scale range (FSR) per °C,

from the value at ambient (25°C) to values over the full operating temperature range.

Offset Error: Defined as the percentage error (in FSR%) for the ratio between the measured mid-scale output

current and the ideal mid-scale output current.

Output Compliance Range: Defined as the minimum and maximum allowable voltage at the output of the

current-output DAC. Exceeding this limit may result reduced reliability of the device or adversely affecting

distortion performance.

Reference Voltage Drift: Defined as the maximum change of the reference voltage in ppm per degree Celsius

from value at ambient (25°C) to values over the full operating temperature range.

Spurious Free Dynamic Range (SFDR): Defined as the difference (in dBc) between the peak amplitude of the

output signal and the peak spurious signal within the first Nyquist zone.

Noise Spectral Density (NSD): Defined as the difference of power (in dBc) between the output tone signal

power and the noise floor of 1Hz bandwidth within the first Nyquist zone.

SERIAL INTERFACE

The serial port of the DAC34H84 is a flexible serial interface which communicates with industry standard

microprocessors and microcontrollers. The interface provides read/write access to all registers used to define the

operating modes of DAC34H84. It is compatible with most synchronous transfer formats and can be configured

as a 3 or 4 pin interface by sif4_ena in register config2. In both configurations, SCLK is the serial interface input

clock and SDENB is serial interface enable. For 3 pin configuration, SDIO is a bidirectional pin for both data in

and data out. For 4 pin configuration, SDIO is data in only and SDO is data out only. Data is input into the device

with the rising edge of SCLK. Data is output from the device on the falling edge of SCLK.

Each read/write operation is framed by signal SDENB (Serial Data Enable Bar) asserted low. The first frame byte

is the instruction cycle which identifies the following data transfer cycle as read or write as well as the 7-bit

address to be accessed. Table 1 indicates the function of each bit in the instruction cycle and is followed by a

detailed description of each bit. The data transfer cycle consists of two bytes

Table 1. Instruction Byte of the Serial Interface

MSB

7

LSB

0

Bit

6

5

4

3

2

1

Description

R/W

A6

A5

A4

A3

A2

A1

A0

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DAC34H84

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R/W

Identifies the following data transfer cycle as a read or write operation. A high indicates a read

operation from DAC34H84 and a low indicates a write operation to DAC34H84.

[A6 : A0]

Identifies the address of the register to be accessed during the read or write operation.

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REGISTER DESCRIPTIONS

Register name: config0 – Address: 0x00, Default: 0x049C

Register

Name

Default

Value

Address

Bit

Name

Function

config0

0x00

15

qmc_offsetAB_ena When set, the digital Quadrature Modulator Correction (QMC) offset

correction for the AB data path is enabled.

0

14

13

12

qmc_offsetCD_ena When set, the digital Quadrature Modulator Correction (QMC) offset

correction for the CD data path is enabled.

0

qmc_corrAB_ena

When set, the QMC phase and gain correction circuitry for the AB

data path is enabled.

0

qmc_corrCD_ena

When set, the QMC phase and gain correction circuitry for the CD

data path is enabled.

0

11:8 interp(3:0)

These bits define the interpolation factor

0100

interp

0000

0001

0010

0100

1000

Interpolation Factor

1x

2x

4x

8x

16x

7

fifo_ena

When set, the FIFO is enabled. When the FIFO is disabled

DACCCLKP/N and DATACLKP/N must be aligned to within

t_(align)(not recommended).

1

6

5

4

Reserved

Reserved for factory use.

0

1

Reserved

alarm_out_ena

When set, the ALARM pin becomes an output. When cleared, the

ALARM pin is 3-stated.

3

2

alarm_out_pol

This bit changes the polarity of the ALARM signal.

MM 0: Negative logic

MM 1: Positive logic

1

clkdiv_sync_ena

When set, enables the syncing of the clock divider and the FIFO

output pointer using the sync source selected by register config32.

The internal divided-down clocks will be phase aligned after syncing.

Refer to the Power-Up Sequence section for more detail.

1

0

invsincAB_ena

invsincCD_ena

When set, the inverse sinc filter for the AB data path is enabled.

When set, the inverse sinc filter for the CD data path is enabled.

0

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DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

Register name: config1 – Address: 0x01, Default: 0x040E

Register

www.ti.com

Default

Value

Address

Bit

Name

Function

Name

config1

0x01

15

iotest_ena

When set, enables the data pattern checker test. The outputs are

0

deactivated regardless of the state of TXENA and sif_txenable.

14

13

12

Reserved

64cnt_ena

Reserved for factory use.

0

When set, enables resetting of the alarms after 64 good samples

with the goal of removing unnecessary errors. For instance, when

checking setup/hold through the pattern checker test, there may

initially be errors. Setting this bit removes the need for a SIF write to

clear the alarm register.

11

oddeven_parity

Selects between odd and even parity check

MM 0: Even parity

0

MM 1: Odd parity

10

9

single_parity_ena

dual_parity_ena

rev_interface

When set, enables parity checking of each input word using the 1

PARITYP/N parity input. It should match the oddeven_parity

register setting.

1

0

When set, enables parity checking using the ISTR signal to 0 source

the parity bit. The parity bit should match the oddeven_parity

register setting.

8

When set, the PARITY, SYNC, and ISTR inputs are rotated to allow

complete reversal of the data interface when setting the

rev_interface bit.

When rev_interface = “1”, the following changes occurs

MM 1. SYNCP/N becomes ISTRP/N

MM 2. PARITYP/N becomes SYNCP/N

MM 3. ISTRP/N becomes PARITYP/N

7

6

5

4

3

2

1

0

dacA_complement

dacB_complement

dacC_complement

dacD_complement

alarm_2away_ena

alarm_1away_ena

alarm_collision_ena

Reserved

When set, the DACA output is complemented. This allows to

effectively change the + and – designations of the LVDS data lines.

0

1

0

When set, the DACB output is complemented. This allows to

effectively change the + and – designations of the LVDS data lines.

When set, the DACC output is complemented. This allows to

effectively change the + and – designations of the LVDS data lines.

When set, the DACD output is complemented. This allows to

effectively change the + and – designations of the LVDS data lines.

When set, the alarm from the FIFO indicating the write and read

pointers being 2 away is enabled.

When set, the alarm from the FIFO indicating the write and read

pointers being 1 away is enabled.

When set, the alarm from the FIFO indicating a collision between the

write and read pointers is enabled.

Reserved for factory use.

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Register name: config2 – Address: 0x02, Default: 0x7000

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config2

0x02

15

14

Reserved for factory use.

0

1

dacclkgone_ena

dataclkgone_ena

collisiongone_ena

When set, the DACCLK-gone signal from the clock monitor circuit can

be used to shut off the DAC outputs. The corresponding alarms,

alarm_dacclk_gone and alarm_output_gone, must not be masked

(i.e.Config7, bit <10> and bit <8> must set to "0").

13

12

When set, the DATACLK-gone signal from the clock monitor circuit

can be used to shut off the DAC outputs. The corresponding alarms,

alarm_dataclk_gone and alarm_output_gone, must not be masked

(i.e.Config7, bit <9> and bit <8> must set to "0").

1

When set, the FIFO collision alarms can be used to shut off the DAC

outputs. The corresponding alarms, alarm_fifo_collision and

alarm_output_gone, must not be masked (i.e.Config7, bit <13> and

bit <8> must set to "0").

11

10

9

Reserved

sif4_ena

Reserved for factory use.

0

8

7

When set, the serial interface (SIF) is a 4 bit interface, otherwise it is

a 3 bit interface.

6

5

4

3

mixer_ena

mixer_gain

nco_ena

revbus

When set, the mixer block is enabled.

0

When set, a 6dB gain is added to the mixer output.

When set, the NCO is enabled. This is not required for coarse mixing.

When set, the input bits for the data bus are reversed. MSB becomes

LSB.

2

1

Reserved

twos

Reserved for factory use.

0

When set, the input data format is expected to be 2’s complement.

When cleared, the input is expected to be offset-binary.

0

Reserved

Reserved for factory use.

0

Register name: config3 – Address: 0x03, Default: 0xF000

Register

Name

Default

Value

Address

Bit

Name

Function

config3

0x03

15:12 coarse_dac(3:0)

Scales the output current in 16 equal steps.

1111

V_EXTIO

I_FS

=

´ 2´ coarse _ dac +1

(

)

R_BIAS

11:8

7:1

0

Reserved

sif_txenable

Reserved for factory use.

0000

0000000

0

Reserved for factory use.

When set, the internal value of TXENABLE is set to “1”.

To enable analog output data transmission, set sif_txenable to “1” or

pull CMOS TXENA pin (N9) to high. To disable analog output, set

sif_txenable to “0” and pull CMOS TXENA pin (N9) to low.

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Register name: config4 – Address: 0x04, Default: No RESET Value (WRITE TO CLEAR)

Register

Name

Default

Value

Address

Bit

Name

Function

config4

0x04

15:0

iotest_results(15:0)

Bits in iotest_results with logic value of “1” tell which bit in either DAB[15:0]

bus or DCD[15:0] bus failed during the pattern checker test.

No RESET

Value

iotest_results(15:8) correspond to the data bits on both DAB[15:8] and

DCD[15:8].

iotest_results(7:0) correspond to the data bits on both DAB[7:0] and DCD[7:0].

Register name: config5 – Address: 0x05, Default: Setup and Power-Up Conditions Dependent (WRITE TO

CLEAR)

Register Address

Name

Default

Value

Bit

Name

Function

config5

0x05

15

alarm_from_zerochk

This alarm indicates the 8-bit FIFO write pointer address has an all

zeros patterns. Due to pointer address being a shift register, this is

not a valid address and will cause the write pointer to be stuck until

the next sync. This error is typically caused by timing error or

improper power start-up sequence. If this alarm is asserted,

resynchronization of FIFO is necessary. Refer to the Power-Up

Sequence section for more detail.

NA

14

Reserved

Reserved for factory use.

NA

13:11 alarms_from_fifo(2:0)

Alarm indicating FIFO pointer collisions and nearness:

MM 000: All fine

MM 001: Pointers are 2 away

MM 01x: Pointers are 1 away

MM 1xx: FIFO pointer collision

If the FIFO pointer collision alarm is set when collisiongone_ena is

enabled, the FIFO must be re-synchronized and the bits must be

cleared to resume normal operation.

10

9

alarm_dacclk_gone

alarm_dataclk_gone

Alarm indicating the DACCLK has been stopped.

If the bit is set when dacclkgone_ena is enabled, the DACCLK must

resume and the bit must be cleared to resume normal operation.

NA

Alarm indicating the DATACLK has been stopped.

If the bit is set when dataclkgone_ena is enabled, the DATACLK

must resume and the bit must be cleared to resume normal

operation.

8

7

alarm_output_gone

alarm_from_iotest

Alarm indicating either alarm_dacclk_gone, alarm_dataclk_gone, or

alarm_fifo_collision are asserted. It controls the output. When high it

will output "0x8000" for each output connected to the DAC. If the bit

is set when dacclkgone_ena, dataclkgone_ena, or

collisiongone_ena are enabled, then the corresponding errors must

be fixed and the bits must be cleared to resume normal operation.

NA

Alarm indicating the input data pattern does not match the pattern in

the iotest_pattern registers. When data pattern checker mode is

enabled, this alarm in register config5, bit7 is the only valid alarm.

Other alarms in register config5 are not valid and can be

disregarded.

6

5

Reserved

Reserved for factory use.

NA

alarm_from_pll

Alarm indicating the PLL has lost lock. For version ID "001",

alarm_from_PLL may not indicate the correct status of the PLL.

Refer to pll_lfvolt(2:0) in register config24 for proper PLL lock

indication.

4

3

alarm_Aparity

alarm_Bparity

In dual parity mode, alarm indicating a parity error on the A word. In

single parity mode, alarm on the 32-bit data captured on the rising

edge of DATACLKP/N.

NA

In dual parity mode, alarm indicating a parity error on the B word. In

single parity mode, alarm on the 32-bit data captured on the falling

edge of DATACLKP/N.

2

1

0

alarm_Cparity

alarm_Dparity

Reserved

In dual parity mode, alarm indicating a parity error on the C word.

In dual parity mode, alarm indicating a parity error on the D word.

Reserved for factory use.

NA

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Register name: config6 – Address: 0x06, Default: No RESET Value (READ ONLY)

Register

Name

Default

Value

Address

Bit

Name

tempdata(7:0)

Function

config6

0x06

15:8

This is the output from the chip temperature sensor. The value of this register in

two’s complement format represents the temperature in degrees Celsius. This

register must be read with a minimum SCLK period of 1μs.

No

RESET

Value

7:2

1

Reserved

Reserved for factory use.

000000

0

Register name: config7 – Address: 0x07, Default: 0xFFFF

Register

Name

Default

Value

Address

Bit

Name

Function

config7

0x07

15:0 alarms_mask(15:0)

These bits control the masking of the alarms. (0=not masked, 1= masked)

0xFFFF

alarm_mask

Alarm that is Masked

alarm_from_zerochk

not used

15

14

13

12

11

10

9

alarm_fifo_collision

alarm_fifo_1away

alarm_fifo_2away

alarm_dacclk_gone

alarm_dataclk_gone

alarm_output_gone

alarm_from_iotest

not used

8

7

6

5

alarm_from_pll

alarm_Aparity

4

3

alarm_Bparity

2

alarm_Cparity

1

alarm_Dparity

0

not used

Register name: config8 – Address: 0x08, Default: 0x0000 (CAUSES AUTO-SYNC)

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config8

0x08

15

14

13

Reserved for factory use.

0

Reserved

0

12:0 qmc_offsetA(12:0)

DACA offset correction. The offset is measured in DAC LSBs. If enabled in config30

writing to this register causes an auto-sync to be generated. This loads the values of

the QMC offset registers (config8-config9) into the offset block at the same time.

When updating the offset values for the AB channel config8 should be written last.

Programming config9 will not affect the offset setting.

All zeros

Register name: config9 – Address: 0x09, Default: 0x8000

Register

Name

Default

Value

Address

Bit

Name

Function

config9

0x09

15:13 fifo_offset(2:0)

When the sync to the FIFO occurs, this is the value loaded into the FIFO read pointer. With

this value the initial difference between write and read pointers can be controlled. This may

be helpful in syncing multiple chips or controlling the delay through the device.

100

12:0 qmc_offsetB(12:0) DACB offset correction. The offset is measured in DAC LSBs.

All zeros

31

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Register name: config10 – Address: 0x0A, Default: 0x0000 (CAUSES AUTO-SYNC)

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config10

0x0A

15

14

13

Reserved for factory use.

0

Reserved

0

12:0 qmc_offsetC(12:0)

DACC offset correction. The offset is measured in DAC LSBs. If enabled in config30

writing to this register causes an auto-sync to be generated. This loads the values of

the CD-channel QMC offset registers (config10-config11) into the offset block at the

same time. When updating the offset values for the CD-channel config10 should be

written last. Programming config11 will not affect the offset setting.

All zeros

Register name: config11 – Address: 0x0B, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config11

0x0B

15

14

Reserved for factory use.

0

Reserved

0

13

Reserved

12:0

qmc_offsetD(12:0)

DACD offset correction. The offset is measured in DAC LSBs.

All zeros

Register name: config12 – Address: 0x0C, Default: 0x0400

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config12

0x0C

15

14

Reserved for factory use.

0

Reserved

13

Reserved

12

Reserved

11

Reserved

10:0

qmc_gainA(10:0)

QMC gain for DACA. The full 11-bit qmc_gainA(10:0) word is formatted as UNSIGNED

with a range of 0 to 1.9990. The implied decimal point for the multiplication is between bit

9 and bit 10.

10000000

000

Register name: config13 – Address: 0x0D, Default: 0x0400

Register

Name

Default

Value

Address

Bit

Name

Function

Sets the mixing function of the coarse mixer.

config13

0x0D

15

cmix_mode(3:0)

0000

MM Bit 15: Fs/8 mixer

MM Bit 14: Fs/4 mixer

MM Bit 13: Fs/2 mixer

MM Bit 12: -Fs/4 mixer

The various mixers can be combined together to obtain a ±n×Fs/8 total mixing factor.

11

Reserved

Reserved for factory use.

0

10:0

qmc_gainB(10:0)

QMC gain for DACB. The full 11-bit qmc_gainB(10:0) word is formatted as UNSIGNED

with a range of 0 to 1.9990. The implied decimal point for the multiplication is between

bit 9 and bit 10.

10000000

000

Register name: config14 – Address: 0x0E, Default: 0x0400

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config14

0x0E

15

14

Reserved for factory use.

0

Reserved

13

Reserved

12

Reserved

11

Reserved

10:0

qmc_gainC(10:0)

QMC gain for DACC. The full 11-bit qmc_gainC(10:0) word is formatted as UNSIGNED 10000000

with a range of 0 to 1.9990. The implied decimal point for the multiplication is between

bit 9 and bit 10.

000

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Register name: config15 – Address: 0x0F, Default: 0x0400

Register

Name

Default

Value

Address

Bit

Name

Function

config15

0x0F

15:14 output_

Delays the AB data path outputs from 0 to 3 DAC clock cycles.

Delays the CD data path outputs from 0 to 3 DAC clock cycles.

Reserved for factory use.

00

0

delayAB(1:0)

13:12 output_

delayCD(1:0)

Reserved

11

10:0

qmc_gainD(10:0)

QMC gain for DACD. The full 11-bit qmc_gainD(10:0) word is formatted as UNSIGNED

with a range of 0 to 1.9990. The implied decimal point for the multiplication is between

bit 9 and bit 10.

10000000

000

Register name: config16 – Address: 0x10, Default: 0x0000 (CAUSES AUTO-SYNC)

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config16

0x10

15

14

Reserved for factory use.

0

Reserved

0

13

Reserved

0

12

Reserved

11:0

qmc_phaseAB(11:0)

QMC correction phase for the AB data path. The 12-bit qmc_phaseAB(11:0) word is

formatted as two’s complement and scaled to occupy a range of -0.5 to 0.49975 and

a default phase correction of 0.00. To accomplish QMC phase correction, this value

is multiplied by the current B sample, then summed into the A sample. If enabled in

config30 writing to this register causes an auto-sync to be generated. This

loads the values of the QMC offset registers (config12, config13, and config16)

into the QMC block at the same time. When updating the QMC values for the

AB channel config16 should be written last. Programming config12 and

config13 will not affect the QMC settings.

All zeros

Register name: config17 – Address: 0x11, Default: 0x0000 (CAUSES AUTO-SYNC)

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config17

0x11

15

14

Reserved for factory use.

0

Reserved

0

13

Reserved

0

12

Reserved

11:0

qmc_phaseCD(11:0)

QMC correction phase for the CD data path. The 12-bit qmc_gainCD(11:0) word is

formatted as two’s complement and scaled to occupy a range of -0.5 to 0.49975

and a default phase correction of 0.00. To accomplish QMC phase correction, this

value is multiplied by the current D sample, then summed into the C sample. If

enabled in config30 writing to this register causes an auto-sync to be

generated. This loads the values of the CD-channel QMC block registers

(config14, config15 and config17) into the QMC block at the same time. When

updating the QMC values for the CD-channel config17 should be written last.

Programming config14 and config15 will not affect the QMC settings.

All zeros

Register name: config18 – Address: 0x12, Default: 0x0000 (CAUSES AUTO-SYNC)

Register

Name

Default

Value

Address

Bit

Name

Function

config18

0x12

15:0

phase_offsetAB(15:0) Phase offset added to the AB data path NCO accumulator before the generation of

the SIN and COS values. The phase offset is added to the upper 16 bits of the NCO

accumulator results and these 16 bits are used in the sin/cos lookup tables. If

enabled in config31 writing to this register causes an auto-sync to be

generated. This loads the values of the fine mixer block registers (config18,

config20, and config21) at the same time. When updating the mixer values the

config18 should be written last. Programming config20 and config21 will not

affect the mixer settings.

0x0000

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Register name: config19 – Address: 0x13, Default: 0x0000 (CAUSES AUTO-SYNC)

Register

Name

Default

Value

Address

Bit

Name

Function

config19

0x13

15:0

phase_offsetCD(15:0)

Phase offset added to the CD data path NCO accumulator before the generation of

the SIN and COS values. The phase offset is added to the upper 16 bits of the NCO

accumulator results and these 16 bits are used in the sin/cos lookup tables. If

enabled in config31 writing to this register causes an auto-sync to be

generated. This loads the values of the CD-channel fine mixer block registers

(config19, config22, and config23) at the same time. When updating the mixer

values for the CD-channel config19 should be written last. Programming

config22 and config23 will not affect the mixer settings.

0x0000

Register name: config20 – Address: 0x14, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Function

config20

0x14

15:0

phase_ addAB(15:0)

The phase_addAB(15:0) value is used to determine the NCO frequency. The two’s

complement formatted value can be positive or negative. Each LSB represents

Fs/(2^32) frequency step.

0x0000

Register name: config21 – Address: 0x15, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Function

config21

0x15

15:0

phase_ addAB(31:16)

See config20 above.

0x0000

Register name: config22 – Address: 0x16, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Function

config22

0x16

15:0

phase_ addCD(15:0)

The phase_addCD(15:0) value is used to determine the NCO frequency. The two’s

complement formatted value can be positive or negative. Each LSB represents

Fs/(2^32) frequency step.

0x0000

Register name: config23 – Address: 0x17, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Function

config23

0x17

15:0

phase_ addCD(31:16)

See config22 above.

0x0000

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Register name: config24 – Address: 0x18, Default: NA

Register

Name

Default

Address

Bit

Name

Function

Value

001

0

config24

0x18

15:13

12

Reserved

pll_reset

Reserved for factory use.

When set, the PLL loop filter (LPF) is pulled down to 0V. Toggle from ‘1’ to ‘0’ to

restart the PLL if an over-speed lock-up occurs. Over-speed can happen when the

process is fast, the supplies are higher than nominal, etc. resulting in the feedback

dividers missing a clock.

11

10

pll_ndivsync_ena

pll_ena

When set, the LVDS SYNC input is used to sync the PLL N dividers.

When set, the PLL is enabled. When cleared, the PLL is bypassed.

Reserved for factory use.

1

0

9:8

7:6

Reserved

00

pll_cp(1:0)

PLL pump charge select

MM 00: No charge pump

MM 01: Single pump charge

MM 10: Not used

MM 11: Dual pump charge

5:3

pll_p(2:0)

PLL pre-scaler dividing module control.

001

MM 010: 2

MM 011: 3

MM 100: 4

MM 101: 5

MM 110: 6

MM 111: 7

MM 000: 8

2:0

pll_lfvolt(2:0)

PLL loop filter voltage. This three bit read-only indicator has step size of 0.4125V.

The entire range covers from 0V to 3.3V. The optimal lock range of the PLL will be

from 010 to 101 (i.e. 0.825V to 2.063V). Adjust pll_vco(5:0) for optimal lock range.

NA

Register name: config25 – Address: 0x19, Default: 0x0440

Register

Name

Default

Value

Address

Bit

Name

pll_m(7:0)

Function

M portion of the M/N divider of the PLL.

config25

0x19

15:8

0x04

If pll_m<7> = 0, the M divider value has the range of pll_m<6:0>, spanning from

4 to 127. (i.e. 0, 1, 2, and 3 are not valid.)

If pll_m<7> = 1, the M divider value has the range of 2 × pll_m<6:0>, spanning

from 8 to 254. (i.e. 0, 2, 4, and 6 are not valid. M divider has even values only.)

7:4

pll_n(3:0)

N portion of the M/N divider of the PLL.

MM 0000: 1

0100

MM 0001: 2

MM 0010: 3

MM 0011: 4

MM 0100: 5

MM 0101: 6

MM 0110: 7

MM 0111: 8

MM 1000: 9

MM 1001: 10

MM 1010: 11

MM 1011: 12

MM 1100: 13

MM 1101: 14

MM 1110: 15

MM 1111: 16

3:2

1:0

pll_vcoitune(1:0)

Reserved

PLL VCO bias tuning bits. Set to "01" for normal PLL operation

Reserved for factory use.

00

35

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

Register name: config26 – Address: 0x1A, Default: 0x0020

Register

Name

Default

Value

Address

Bit

Name

pll_vco(5:0)

Function

config26

0x1A

15:10

VCO frequency coarse tuning bits.

Reserved for factory use.

000000

9

8

7

6

5

4

Reserved

0

1

0

Reserved

Reserved for factory use.

bias_sleep

tsense_sleep

pll_sleep

When set, the bias amplifier is put into sleep mode.

Turns off the temperature sensor when asserted.

When set, the PLL is put into sleep mode.

clkrecv_sleep

When asserted the clock input receiver gets put into sleep mode. This affects the

OSTR receiver as well.

3

2

1

0

sleepA

sleepB

sleepC

sleepD

When set, the DACA is put into sleep mode.

When set, the DACB is put into sleep mode.

When set, the DACC is put into sleep mode.

When set, the DACD is put into sleep mode.

0

Register name: config27 – Address: 0x1B, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

extref_ena

Function

config27

0x1B

15

Allows the device to use an external reference or the internal reference.

0: Internal reference

0

1: External reference

14

13

12

11

Reserved

fuse_sleep

Reserved for factory use.

0

Put the fuses to sleep when set high.

Note: Default value is ‘0’. Must be set to ‘1’ for proper operation

10

9

Reserved

atest

Reserved for factory use.

0

8

0

7

0

6

5:0

ATEST mode allows the user to check for the internal die voltages to ensure the

supply voltages are within the range. When ATEST mode is programmed, the

internal die voltages can be measured at the TXENA pin. The TXENA pin (N9) must

be floating without any pull-up or pull-down resistors.

000000

In ATEST mode, the TXENA and sif_txenable logics are bypassed, and output will

be active at all time.

Config27, bit<5:0>

001110

Description

DACA AVSS

DACA DVDD

DACA AVDD

DACB AVSS

DACB DVDD

DACB AVDD

DACC AVSS

DACC DVDD

DACC AVDD

DACD AVSS

DACD DVDD

DACD AVDD

1.2VDIG

Expected Nominal Voltage

0V

001111

1.2V

3.3V

0V

010000

010110

010111

1.2V

3.3V

0V

011000

011110

011111

1.2V

3.3V

0V

100000

100110

100111

1.2V

3.3V

1.2V

101000

110000

000101

1.2VCLK

36

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

Register name: config28 – Address: 0x1C, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Function

config28

0x1C

15:8

7:0

Reserved

Reserved for factory use.

0x00

Register name: config29 – Address: 0x1D, Default: 0x0000

Register

Name

Default

Address

Bit

Name

Function

Value

0x00

config29

0x1D

15:8

7:0

Reserved

Reserved for factory use.

Register name: config30 – Address: 0x1E, Default: 0x1111

Register

Name

Default

Value

Address

Bit

Name

Function

config30

0x1E

15:12 syncsel_qmoffsetAB(3:0) Selects the syncing source(s) of the AB data path double buffered QMC offset

registers. A ‘1’ in the bit enables the signal as a sync source. More than one sync

source is permitted.

0001

MM Bit 15: sif_sync (via config31)

MM Bit 14: SYNC

MM Bit 13: OSTR

MM Bit 12: Auto-sync from register write

11:8

syncsel_qmoffsetCD(3:0) Selects the syncing source(s) of the CD data path double buffered QMC offset

registers. A ‘1’ in the bit enables the signal as a sync source. More than one sync

source is permitted.

MM Bit 11: sif_sync (via config31)

MM Bit 10: SYNC

MM Bit 9: OSTR

MM Bit 8: Auto-sync from register write

7:4

syncsel_qmcorrAB(3:0)

syncsel_qmcorrCD(3:0)

Selects the syncing source(s) of the AB data path double buffered QMC offset

registers. A ‘1’ in the bit enables the signal as a sync source. More than one sync

source is permitted.

MM Bit 7: sif_sync (via config31)

MM Bit 6: SYNC

MM Bit 5: OSTR

MM Bit 4: Auto-sync from register write

3:0

Selects the syncing source(s) of the CD data path double buffered QMC offset

registers. A ‘1’ in the bit enables the signal as a sync source. More than one sync

source is permitted.

MM Bit 3: sif_sync (via config31)

MM Bit 2: SYNC

MM Bit 1: OSTR

MM Bit 0: Auto-sync from register write

37

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

Register name: config31 – Address: 0x1F, Default: 0x1140

Register

Name

Default

Value

Address

Bit

Name

Function

config31

0x1F

15:12 syncsel_mixerAB(3:0)

Selects the syncing source(s) of the AB data path double buffered mixer

registers. A ‘1’ in the bit enables the signal as a sync source. More than one

sync source is permitted.

MM Bit 15: sif_sync (via config31)

MM Bit 14: SYNC

MM Bit 13: OSTR

MM Bit 12: Auto-sync from register write

0001

11:8

syncsel_mixerCD(3:0)

Selects the syncing source(s) of the CD data path double buffered mixer

registers. A ‘1’ in the bit enables the signal as a sync source. More than one

sync source is permitted.

MM Bit 11: sif_sync (via config31)

MM Bit 10: SYNC

MM Bit 9: OSTR

MM Bit 8: Auto-sync from register write

7:4

3:2

syncsel_nco(3:0)

syncsel_fifo_input

Selects the syncing source(s) of the two NCO accumulators. A ‘1’ in the bit

enables the signal as a sync source. More than one sync source is permitted.

MM Bit 7: sif_sync (via config31)

MM Bit 6: SYNC

MM Bit 5: OSTR

0100

MM Bit 4: ISTR

Selects either ISTR or SYNC LVDS signal to be routed to the internal

FIFO_ISTR path if syncsel_fifoin(3:0) is set to be ISTR (i.e. syncsel_fifoin(3:0) =

“0010”). In conjunction with config1 register bit(8), this allows flexibility of

external LVDS signal routing to the internal FIFO. The syncsel_fifo_input(1:0)

can only have one bit active at a time.

00

MM 00: external LVDS ISTR signal to internal FIFO_ISTR path

MM 01: external LVDS SYNC signal to internal FIFO_ISTR path

MM 10: external LVDS ISTR signal to internal FIFO_ISTR path

MM 11: external LVDS SYNC signal to internal FIFO_ISTR path

1

0

sif_sync

SIF created sync signal. Set to ‘1’ to cause a sync and then clear to ‘0’ to

remove it.

0

Reserved

Reserved for factory use.

Register name: config32 – Address: 0x20, Default: 0x2400

Register

Name

Default

Value

Address

Bit

Name

Function

config32

0x20

15:12

syncsel_fifoin(3:0)

Selects the syncing source(s) of the FIFO input side. A ‘1’ in the bit enables the

0010

signal as a sync source. More than one sync source is permitted.

MM Bit 15: sif_sync (via config31)

MM Bit 14: Always zero

MM Bit 13: ISTR

MM Bit 12: SYNC

11:8

syncsel_fifoout(3:0)

Selects the syncing source(s) of the FIFO output side. A ‘1’ in the bit enables the

signal as a sync source. More than one sync source is permitted. clkdiv_sync_ena

must be set to "1" for the FIFO output pointer sync to occur.

0100

MM Bit 11: sif_sync (via config31)

MM Bit 10: OSTR – Dual Sync Sources Mode

MM Bit 9: ISTR – Single Sync Source mode

MM Bit 8: SYNC – Single Sync Source mode

7:1

0

Reserved

Reserved for factory use.

0000

0

clkdiv_sync_sel

Selects the signal source for clock divider synchronization.

clkdiv_sync_sel

Sync Source

0

1

OSTR

ISTR or SYNC, based on syncsel_fifoin source

selection

(config32, bit<15:12>)

Register name: config33 – Address: 0x21, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config33

0x21

15:0

Reserved for factory use.

0x0000

38

DAC34H84

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SLAS751A –MARCH 2011–REVISED JUNE 2011

Register name: config34 – Address: 0x22, Default: 0x1B1B

Register

Name

Default

Value

Address

Bit

Name

Function

config34

0x22

15:14

13:12

11:10

9:8

pathA_in_sel(1:0)

pathB_in_sel(1:0)

pathC_in_sel(1:0)

pathD_in_sel(1:0)

DACA_out_sel(1:0)

DACB_out_sel(1:0)

DACC_out_sel(1:0)

DACD_out_sel(1:0)

Selects the word used for the A channel path.

Selects the word used for the B channel path.

Selects the word used for the C channel path.

Selects the word used for the D channel path.

Selects the word used for the DACA output.

Selects the word used for the DACB output.

Selects the word used for the DACC output.

Selects the word used for the DACD output.

00

01

10

11

00

01

10

11

7:6

5:4

3:2

1:0

Register name: config35 – Address: 0x23, Default: 0xFFFF

Register

Name

Default

Value

Address

Bit

Name

Function

config35

0x23

15:0

sleep_cntl(15:0)

Controls the routing of the CMOS SLEEP signal (pin B40) to different blocks. When a

bit in this register is set, the SLEEP signal will be sent to the corresponding block. The

block will only be disabled when the SLEEP is logic HIGH and the correspond bit is set

to “1”.

0xFFFF

These bits do not override SIF bits in config26 that control the same sleep function.

sleep_cntl(bit)

Function

DACA sleep

15

14

DACB sleep

13

DACC sleep

12

DACD sleep

11

Clock receiver sleep

PLL sleep

10

9

LVDS data sleep

LVDS control sleep

Temp sensor sleep

reserved

8

7

6

5

Bias amplifier sleep

not used

All others

Register name: config36 – Address: 0x24, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Function

config36

0x24

15:13 datadly(2:0)

Controls the delay of the data inputs through the LVDS receivers. Each LSB adds

approximately 50 ps

000

0: Minimum

12:10 clkdly(2:0)

Controls the delay of the data clock through the LVDS receivers. Each LSB adds

approximately 50 ps

000

0: Minimum

9:0

Reserved

Reserved for factory use.

0x000

Register name: config37 – Address: 0x25, Default: 0x7A7A

Register

Name

Default

Value

Address

Bit

Name

Function

config37

0x25

15:0

iotest_pattern0

Dataword0 in the IO test pattern. It is used with the seven other words to test the input data.

0x7A7A

At the start of the IO test pattern, this word should be aligned with rising edge of ISTR or

SYNC signal to indicate sample 0.

39

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

Register name: config38 – Address: 0x26, Default: 0xB6B6

Register

Name

Default

Value

Address

Bit

Name

Function

config38

0x26

15:0

iotest_pattern1

Dataword1 in the IO test pattern. It is used with the seven other words to test the input data.

0xB6B6

Register name: config39 – Address: 0x27, Default: 0xEAEA

Register

Name

Default

Value

Address

Bit

Name

Function

config39

0x27

15:0

iotest_pattern2

Dataword2 in the IO test pattern. It is used with the seven other words to test the input

data.

0xEAEA

Register name: config40 – Address: 0x28, Default: 0x4545

Register

Name

Default

Value

Address

Bit

Name

Function

Dataword3 in the IO test pattern. It is used with the seven other words to test the input data.

config40

0x28

15:0

iotest_pattern3

0x4545

Register name: config41 – Address: 0x29, Default: 0x1A1A

Register

Name

Default

Value

Address

Bit

Name

Function

config41

0x29

15:0

iotest_pattern4 Dataword4 in the IO test pattern. It is used with the seven other words to test the input data.

0x1A1A

Register name: config42 – Address: 0x2A, Default: 0x1616

Register

Name

Default

Value

Address

Bit

Name

Function

config42

0x2A

15:0

iotest_pattern5

Dataword5 in the IO test pattern. It is used with the seven other words to test the input

data.

0x1616

Register name: config43 – Address: 0x2B, Default: 0xAAAA

Register

Name

Default

Value

Address

Bit

Name

Function

config43

0x2B

15:0

iotest_pattern6

Dataword6 in the IO test pattern. It is used with the seven other words to test the input

data.

0xAAAA

Register name: config44 – Address: 0x2C, Default: 0xC6C6

Register

Name

Default

Value

Address

Bit

Name

Function

config44

0x2C

15:0

iotest_pattern7

Dataword7 in the IO test pattern. It is used with the seven other words to test the input

data.

0xC6C6

Register name: config45 – Address: 0x2D, Default: 0x0004

Register

Name

Default

Value

Address

Bit

Name

Reserved

Function

config45

0x2D

15

14

Reserved for factory use.

0

ostrtodig_sel

When set, the OSTR signal is passed directly to the digital block. This is the signal that

is used to clock the dividers.

13

ramp_ena

Reserved

When set, a ramp signal is inserted in the input data at the FIFO input.

Reserved for factory use.

0

12:1

0000

0100

0

sifdac_ena

When set, the DAC output is set to the value in sifdac(15:0) in register config48.

0

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DAC34H84

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SLAS751A –MARCH 2011–REVISED JUNE 2011

Register name: config46 – Address: 0x2E, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Function

config46

0x2E

15:8

grp_delaya(7:0)

Sets the group delay function for DACA. The maximum delay ranges from 30ps to

100ps and is dependent on DAC sample clock. Contact TI for specific application

information.

0x00

7:0

grp_delayB(7:0)

Sets the group delay function for DACB. The maximum delay ranges from 30ps to

100ps and is dependent on DAC sample clock. Contact TI for specific application

information.

0x00

Register name: config47 – Address: 0x2F, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

Function

config47

0x2F

15:8

grp_delayC(7:0)

Sets the group delay function for DACC. The maximum delay ranges from 30ps to

100ps and is dependent on DAC sample clock. Contact TI for specific application

information.

0x00

7:0

grp_delayD(7:0)

Sets the group delay function for DACD. The maximum delay ranges from 30ps to

100ps and is dependent on DAC sample clock. Contact TI for specific application

information.

0x00

Register name: config48 – Address: 0x30, Default: 0x0000

Register

Name

Default

Value

Address

Bit

Name

sifdac(15:0)

Function

config48

0x30

15:0

Value sent to the DACs when sifdac_ena is asserted. DATACLK must be running to

latch this value into the DACs. The format would be based on twos in register config2.

0x0000

Register name: version– Address: 0x7F, Default: 0x5408 (READ ONLY)

Register

Name

Default

Value

Address

Bit

Name

Function

version

0x7F

15:10

9

Reserved

Reserved for factory use.

Returns ‘01’ for DAC34H84.

010101

0

8:7

6:5

4:3

2:0

00

deviceid(1:0)

versionid(2:0)

01

A hardwired register that contains the version of the chip.

001

41

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

DATA INTERFACE

The DAC34H84 has a 32-bit LVDS bus that accepts quad, 16-bit data in word-wide format. The quad-16-bit data

can be input to the device using a dual-bus, 16-bit interface. The bus accepts LVDS transfer rates up to

1.25GSPS which corresponds to a maximum data rate of 625MSPS per data channel. The default LVDS bus

input assignment is shown in Table 3.

Table 3. LVDS Bus Input Assignment

Data Paths

A and B

Pins

DAB[15..0]

DCD[15..0]

C and D

Data is sampled by the LVDS double data rate (DDR) clock DATACLK. Setup and hold requirements must be

met for proper sampling. A and C data are captured on the rising edge of DATACLK. B and D data are captured

on the falling edge of DATACLK.

For both input bus modes, a sync signal, either ISTR or SYNC, is required to sync the FIFO read and/or write

pointers.

The sync signal, either ISTR or SYNC, can be either a pulse or a periodic signal where the sync period

corresponds to multiples of 8 samples. ISTR or SYNC is sampled by a rising edge in DATACLK. The pulse-width

t_{(ISTR_SYNC)}needs to be at least equal to 1/2 of the DATACLK period.

DATA FORMAT

The 16-bit data for channels A and B is interleaved in the form A₀[15:0], B₀[15:0], A₁[15:0], B₁[15:0], A₂[15:0]…

into the DAB[15:0]P/N LVDS inputs. Similarly data for channels C and D is interleaved into the DCD[15:0]P/N

LVDS inputs. Data into the DAC34H84 is formatted according to the diagram shown in Figure 51 where index 0

is the data LSB and index 15 is the data MSB.

SAMPLE 0

SAMPLE 1

SAMPLE 2

SAMPLE 3

A₀

B₀

A₁

B₁

A₂

B₂

A₃

B₃

DAB[15:0]P/N

DCD[15:0]P/N

[15:0]

C₀

D₀

C₁

D₁

C₂

D₂

C₃

D₃

[15:0]

DATACLKP/N (DDR)

t_{(ISTR_SYNC)}

Sync

Option #1

ISTRP/N

t_{(ISTR_SYNC)}

Sync

SYNCP/N

Option #2

T0530-01

Figure 51. Data Transmission Format

The FIFO read and write pointer can also be synced by SIF SYNC as the third sync option if multi-device

synchronization is not needed. In this sync mode, the syncsel_fifoin(3:0) and syncsel_fifoout(3:0) in register

config32 need to be both set to "1000" for the SIF SYNC option.

42

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

INPUT FIFO

The DAC34H84 includes a 4-channel, 16-bits wide and 8-samples deep input FIFO which acts as an elastic

buffer. The purpose of the FIFO is to absorb any timing variations between the input data and the internal DAC

data rate clock such as the ones resulting from clock-to-data variations from the data source.

Figure 52 shows a simplified block diagram of the FIFO.

Clock Handoff

Input Side

Clocked by DATACLK

Output Side

Clocked by FIFO Out Clock

(DACCLK/Interpolation Factor)

FIFO:

4 x 16-Bits Wide

8-Samples deep

16-Bit

DAB[15:0]

Initial

Position

Sample 0

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7

A₀[15:0], B₀[15:0], C₀[15:0], D₀[15:0]

16-Bit

A-Data, 16-Bit

FIFO A Output

Sample 0

A₁[15:0], B₁[15:0], C₁[15:0], D₁[15:0]

16-Bit

B-Data, 16-Bit

C-Data, 16-Bit

D-Data, 16-Bit

64-Bit

FIFO B Output

FIFO C Output

FIFO D Output

64-Bit

16-Bit

Sample 0

A₂[15:0], B₂[15:0], C₂[15:0], D₂[15:0]

De-Interleave

DCD[15:0]

Sample 0

A₃[15:0], B₃[15:0], C₃[15:0], D₃[15:0]

Initial

Position

Sample 0

A₄[15:0], B₄[15:0], C₄[15:0], D₄[15:0]

Sample 0

A₅[15:0], B₅[15:0], C₅[15:0], D₅[15:0]

16-Bit

Sample 0

A₆[15:0], B₆[15:0], C₆[15:0], D₆[15:0]

Read Pointer Reset

Write Pointer Reset

ISTR/

SYNC

Sample 0

A₇[15:0], B₇[15:0], C₇[15:0], D₇[15:0]

FIFO Reset

fifo_offset(2:0)

syncsel_fifoout

S

M

OSTR

syncsel_fifoin

S (Single Sync Sources Mode): Reset handoff from

input side to output side

M (Dual Sync Source Mode): OSTR resets read

pointer. Allows Multi-DAC synchronization

B0461-01

Figure 52. DAC34H84 FIFO Block Diagram

Data is written to the device 32-bits at a time on the rising and falling edges of DATACLK. In order to form a

complete 64-bit wide sample (16-bit A-data, 16-bit B-data, 16-bit C-data, and 16-bit D-data) one DATACLK

period is required. Each 64-bit wide sample is written into the FIFO at the address indicated by the write pointer.

Similarly, data from the FIFO is read by the FIFO Out Clock 64-bits at a time from the address indicated by the

read pointer. The FIFO Out Clock is generated internally from the DACCLK signal and its rate is equal to

DACCLK/Interpolation. Each time a FIFO write or FIFO read is done the corresponding pointer moves to the next

address.

The reset position for the FIFO read and write pointers is set by default to addresses 0 and 4 as shown in

Figure 52. This offset gives optimal margin within the FIFO. The default read pointer location can be set to

another value using fifo_offset(2:0) in register config3 (address 4 by default). Under normal conditions data is

written-to and read-from the FIFO at the same rate and consequently the write and read pointer gap remains

constant. If the FIFO write and read rates are different, the corresponding pointers will be cycling at different

speeds which could result in pointer collision. Under this condition the FIFO attempts to read and write data from

the same address at the same time which will result in errors and thus must be avoided.

The write pointer sync source is selected by syncsel_fifoin(3:0) in register config32. In most applications either

ISTR or SYNC are used to reset the write pointer. Unlike DATA, the sync signal is latched only on the rising

edges of DATACLK. A rising edge on the sync signal source causes the pointer to return to its original position.

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DAC34H84

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Similarly, the read pointer sync source is selected by syncsel_fifoout(3:0). The write pointer sync source can be

set to reset the read pointer as well. In this case, the FIFO Out clock will recapture the write pointer sync signal

to reset the read pointer. This clock domain transfer (DATACLK to FIFO Out Clock) results in phase ambiguity of

the sync signal. This limits the precise control of the output timing and makes full synchronization of multiple

devices difficult.

To alleviate this, the device offers the alternative of resetting the FIFO read pointer independently of the write

pointer by using the OSTR signal. The OSTR signal is sampled by DACCLK and must satisfy the timing

requirements in the specifications table. In order to minimize the skew it is recommended to use the same clock

distribution device such as Texas Instruments CDCE62005 to provide the DACCLK and OSTR signals to all the

DAC34H84 devices in the system. Swapping the polarity of the DACCLK outputs with respect to the OSTR ones

establishes proper phase relationship.

The FIFO pointers reset procedure can be done periodically or only once during initialization as the pointers

automatically return to the initial position when the FIFO has been filled. To reset the FIFO periodically, it is

necessary to have the ISTR, SYNC, and OSTR signals to repeat at multiples of 8 FIFO samples. To disable

FIFO reset, set syncsel_fifoin(3:0) and syncsel_fifoout(3:0) to “0000”.

The frequency limitation for ISTR and SYNC signals are the following:

f_sync= f_DATACLK/(n x 8) where n = 1, 2, …

The frequency limitation for the OSTR signal is the following:

f_OSTR= f_DAC/(n x interpolation x 8) where n = 1, 2, …

The frequencies above are at maximum when n = 1. This is when the ISTR, SYNC, or OSTR have a rising edge

transition every 8 FIFO samples. The occurrence can be made less frequent by setting n > 1, for example, every

n × 8 FIFO samples.

D[15:0]P/N

t_S(DATA)

t_H(DATA)

t_S(DATA)

t_H(DATA)

DATACLKP/N

(DDR)

t_H(DATA)

t_S(DATA)

ISTRP/N

SYNCP/N

Resets Write Pointer to Position 0

DACCLKP/N

2x Interpolation

t_S(OSTR)

t_H(OSTR)

OSTRP/N

(optionally internal

sync from Write Reset)

Resets Read Pointer to Position

Set by fifo_offset (4 by Default)

T0531-01

Figure 53. FIFO Write and Read Descriptions

FIFO MODES OF OPERATION

The DAC34H84 input FIFO can be completely bypassed through registers config0 and config32. The register

configuration for each mode is described in Table 4.

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Register

config0

Control Bits

fifo_ena

config32

syncsel_fifoout(3:0)

Table 4. FIFO Operation Modes

config0 and config32 FIFO Bits

FIFO Mode

syncsel_fifoout

fifo_ena

Bit 3: sif_sync

Bit 2: OSTR

Bit 1: ISTR

Bit 0: SYNC

Dual Sync Sources

1

0

X

1

0

Single Sync

Source

1 or 0 Depends on the sync

source

1 or 0 Depends on the

sync source

0

Bypass

X

DUAL SYNC SOURCES MODE

This is the recommended mode of operation for those applications that require precise control of the output

timing. In Dual Sync Sources mode, the FIFO write and read pointers are reset independently. The FIFO write

pointer is reset using the LVDS ISTR or SYNC signal, and the FIFO read pointer is reset using the LVPECL

OSTR signal. This allows LVPECL OSTR signal to control the phase of the output for either a single chip or

multiple chips. Multiple devices can be fully synchronized in this mode.

SINGLE SYNC SOURCE MODE

In Single Sync Source mode, the FIFO write and read pointers are reset from the same source, either LVDS

ISTR or LVDS SYNC signal. This mode has a possibility of up to 2 DAC clocks offset between the multiple DAC

outputs. Applications requiring exact output timing control will need Dual Sync Sources mode instead of Single

Sync Source Mode. A single rising edge for FIFO and clock divider sync is recommended. Periodic sync signal is

not recommended due to the non-deterministic latency of the sync signal through the clock domain transfer.

BYPASS MODE

In FIFO bypass mode, the FIFO block is not used. As a result the input data is handed off from the DATACLK to

the DACCLK domain without any compensation. In this mode the relationship between DATACLK and DACCLK

t_(align)is critical and used as a synchronizing mechanism for the internal logic. Due to the t_(align)constraint this

mode is not recommended. In bypass mode the pointers have no effect on the data path or handoff.

CLOCKING MODES

The DAC34H84 has a dual clock setup in which a DAC clock signal is used to clock the DAC cores and internal

digital logic and a separate DATA clock is used to clock the input LVDS receivers and FIFO input. The

DAC34H84 DAC clock signal can be sourced directly or generated through an on-chip low-jitter phase-locked

loop (PLL).

In those applications requiring extremely low noise it is recommended to bypass the PLL and source the DAC

clock directly from a high-quality external clock to the DACCLK input. In most applications system clocking can

be simplified by using the on-chip PLL to generate the DAC core clock while still satisfying performance

requirements. In this case the DACCLK pins are used as the reference frequency input to the PLL.

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16-Bit

DACI

PLL

DACCLK

Clock Distribution

to Digital

16-Bit

DACQ

VCO/

Dividers

pll_ena

B0452-01

Figure 54. Top Level Clock Diagram

PLL BYPASS MODE

In PLL bypass mode a very high quality clock is sourced to the DACCLK inputs. This clock is used to directly

source the DAC34H84 DAC sample rate clock. This mode gives the device best performance and is

recommended for extremely demanding applications.

The bypass mode is selected by setting the following:

1. pll_ena bit in register config24 to “0” to bypass the PLL circuitry.

2. pll_sleep bit in register config26 to “1” to put the PLL and VCO into sleep mode.

PLL MODE

In this mode the clock at the DACCLKP/N input functions as a reference clock source to the on-chip PLL. The

on-chip PLL will then multiply this reference clock to supply a higher frequency DAC sample rate clock. Figure 55

shows the block diagram of the PLL circuit.

OSTR (Internally Generated)

External Loop

Filter

DACCLKP

REFCLK

DACCLKN

PFD

and

CP

N

Divider

Prescaler

DACCLK

SYNCP

SYNCN

SYNC_PLL

VCO

Internal Loop

Filter

Note:

The PLL generates internal OSTR signal. In this mode

external LVPECL OSTR signal is not required.

M

Divider

If the DAC is configured with PLL enabled with Dual Sync

Sources mode, then the PFD frequency has to be the pre-

defined OSTR frequency.

B0453-01

Figure 55. PLL Block Diagram

The DAC34H84 PLL mode is selected by setting the following:

1. pll_ena bit in register config24 to “1” to route to the PLL clock path.

2. pll_sleep bit in register config26 to “0” to enable the PLL and VCO.

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The output frequency of the VCO is designed to be the in the range from 3.3GHz to 4.0GHz. The prescaler

value, pll_p(2:0) in register config24, should be chosen such that the product of the prescaler value and DAC

sample rate clock is within the VCO range. To maintain optimal PLL loop, the coarse tune bits, pll_vco(5:0) in

register config26, can adjust the center frequency of the VCO towards the product of the prescaler value and

DAC sample rate clock. Figure 56 shows a typical relationship between coarse tune bits and VCO center

frequency.

4000

VCO Frequency MHz - 3253

)

(

Coarse Tune Bits @

3900

3800

3700

3600

3500

3400

3300

11.6

0

8

16

32

40

48

56

64

24

Coarse Tuning Bits

G047

Figure 56. Typical PLL/VCO Lock Range vs Coarse Tuning Bits

Common wireless infrastructure frequencies (614.4MHz, 737.28MHz, 1.2288GHz, etc.) are generated from this

VCO frequency in conjunction with the pre-scaler setting as shown in Table 5.

Table 5. VCO Operation

VCO Frequency (MHz)

3440.64

Pre-Scale Divider

Desired DACCLK (MHz)

pll_p(2:0)

111

7

6

5

3

491.52

614.4

3686.4

110

3686.4

737.28

1228.8

101

3686.4

011

The M divider is used to determine the phase-frequency-detector (PFD) and charge-pump (CP) frequency.

Table 6. PFD and CP Operation

DACCLK Frequency

M Divider

PDF Update Rate (MHz)

pll_m(7:0)

(MHz)

491.52

4

8

122.88

61.44

30.72

15.36

00000100

00001000

00010000

00100000

16

32

The N divider in the loop allows the PFD to operate at a lower frequency than the reference clock. Both M and N

dividers can keep the PFD frequency below 155 MHz for peak operation.

The overall divide ratio inside the loop is the product of the Pre-Scale and M dividers (P × M) and the following

guidelines should be followed:

•

The overall divide ratio range is from 24 to 480

When the overall divide ratio is less than 120, the internal loop filter can assure a stable loop

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DAC34H84

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•

When the overall divide ratio is greater than 120, an external loop filter is required to ensure loop stability

The single charge pump current option is selected by setting pll_cp(1:0) in register config24 to “01”. If an external

filter is required, the following filter should be connected to the LPF pin (A1):

LPF

R = 1 kΩ

C2 = 1 nF

C1 = 100 nF

S0514-01

Figure 57. Recommended External Loop Filter

The PLL will generate an internal OSTR signal and does not require the external LVPECL OSTR signal. The

OSTR signal is buffered from the N-divider output in the PLL block, and the frequency of the signal is the same

as the PFD frequency. Therefore, using PLL with Dual Sync Sources mode would require the PFD frequency to

be the pre-defined OSTR frequency. This will allow the FIFO to be synced correctly by the internal OSTR.

MULTI-DEVICE SYNCHRONIZATION

In various applications, such as multi antenna systems where the various transmit channels information is

correlated, it is required that multiple DAC devices are completely synchronized such that their outputs are phase

aligned. The DAC34H84 architecture supports this mode of operation.

MULTI-DEVICE SYNCHRONIZATION: PLL BYPASSED WITH DUAL SYNC SOURCES MODE

For single- or multi-device synchronization it is important that delay differences in the data are absorbed by the

device so that latency through the device remains the same. Furthermore, to ensure that the outputs from each

DAC are phase aligned it is necessary that data is read from the FIFO of each device simultaneously. In the

DAC34H84 this is accomplished by operating the multiple devices in Dual Sync Sources mode. In this mode the

additional OSTR signal is required by each DAC34H84 to be synchronized.

Data into the device is input as LVDS signals from one or multiple baseband ASICs or FPGAs. Data into multiple

DAC devices can experience different delays due to variations in the digital source output paths or board level

wiring. These different delays can be effectively absorbed by the DAC34H84 FIFO so that all outputs are phase

aligned correctly.

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DACCLKP/N

OSTRP/N

DAB[15:0]P/N

DCD[15:0]P/N

FPGA

DAC34H84 DAC1

ISTRP/N

Delay 1

LVPECL Outputs

DATACLKP/N

Outputs are

Phase Aligned

Variable delays due to variations in the FPGA(s) output

paths or board level wiring or temperature/voltage deltas

PLL/

DLL

Clock Generator

LVPECL Outputs

DAB[15:0]P/N

DCD[15:0]P/N

ISTRP/N

DATACLKP/N

OSTRP/N

Delay 2

DAC34H84 DAC2

DACCLKP/N

B0454-02

Figure 58. SynchronizationSystem in Dual Sync Sources Mode with PLL Bypassed

For correct operation both OSTR and DACCLK must be generated from the same clock domain. The OSTR

signal is sampled by DACCLK and must satisfy the timing requirements in the specifications table. If the clock

generator does not have the ability to delay the DACCLK to meet the OSTR timing requirement, the polarity of

the DACCLK outputs can be swapped with respect to the OSTR ones to create 180 degree phase delay of the

DACCLK. This may help establish proper setup and hold time requirement of the OSTR signal.

Careful board layout planning must be done to ensure that the DACCLK and OSTR signals are distributed from

device to device with the lowest skew possible as this will affect the synchronization process. In order to

minimize the skew across devices it is recommended to use the same clock distribution device to provide the

DACCLK and OSTR signals to all the DAC devices in the system.

DACCLKP/N(1)

t_S(OSTR)

t_H(OSTR)

t_{SKEW ~ 0}

OSTRP/N(1)

DACCLKP/N(2)

OSTRP/N(2)

t_S(OSTR)

t_H(OSTR)

•

T0526-02

Figure 59. Timing Diagram for LVPECL Synchronization Signals

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The following steps are required to ensure the devices are fully synchronized. The procedure assumes all the

DAC34H84 devices have a DACCLK and OSTR signal and must be carried out on each device.

1. Start-up the device as described in the power-up sequence. Set the DAC34H84 in Dual Sync Sources mode

and select OSTR as the clock divider sync source (clkdiv_sync_sel in register config32).

2. Sync the clock divider and FIFO pointers.

3. Verify there are no FIFO alarms either through register config5 or through the ALARM pin.

4. Disable clock divider sync by setting clkdiv_sync_ena to “0” in register config0.

After these steps all the DAC34H84 outputs will be synchronized.

MULTI-DEVICE SYNCHRONIZATION: PLL ENABLED WITH DUAL SYNC SOURCES MODE

The DAC34H84 allows exact phase alignment between multiple devices even when operating with the internal

PLL clock multiplier. In PLL clock mode, the PLL generates the DAC clock and an internal OSTR signal from the

reference clock applied to the DACCLK inputs so there is no need to supply an additional LVPECL OSTR signal.

For this method to operate properly the SYNC signal should be set to reset the PLL N dividers to a known state

by setting pll_ndivsync_ena in register config24 to “1”. The SYNC signal resets the PLL N dividers with a rising

edge, and the timing relationship t_{s(SYNC_PLL)}and t_{h(SYNC_PLL)}are relative to the reference clock presented on the

DACCLK pin.

Both SYNC and DACCLK can be set as low frequency signals to greatly simplifying trace routing (SYNC can be

just a pulse as a single rising edge is required, if using a periodic signal it is recommended to clear the

pll_ndivsync_ena bit after resetting the PLL dividers). Besides the t_{s(SYNC_PLL)}and t_{h(SYNC_PLL)}requirement

between SYNC and DACCLK, there is no additional required timing relationship between the SYNC and ISTR

signals or between DACCLK and DATACLK. The only restriction as in the PLL disabled case is that the DACCLK

and SYNC signals are distributed from device to device with the lowest skew possible.

DACCLKP/N

SYNCP/N

DAB[15:0]P/N

DCD[15:0]P/N

FPGA

DAC34H84 DAC1

ISTRP/N

Delay 1

Outputs

DATACLKP/N

Outputs are

Phase Aligned

Variable delays due to variations in the FPGA(s) output

paths or board level wiring or temperature/voltage deltas

PLL/

DLL

Clock Generator

Outputs

DAB[15:0]P/N

DCD[15:0]P/N

ISTRP/N

DATACLKP/N

SYNCP/N

Delay 2

DAC34H84 DAC2

DACCLKP/N

B0455-02

Figure 60. Synchronization System in Dual Sync Sources Mode with PLL Enabled

The following steps are required to ensure the devices are fully synchronized. The procedure assumes all the

DAC34H84 devices have a DACCLK and OSTR signal and must be carried out on each device.

1. Start-up the device as described in the power-up sequence. Set the DAC34H84 in Dual Sync Sources mode

and enable SYNC to reset the PLL dividers (set pll_ndivsync_ena in register config24 to "1").

2. Reset the PLL dividers with a rising edge on SYNC.

3. Disable PLL dividers resetting.

4. Sync the clock divider and FIFO pointers.

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5. Verify there are no FIFO alarms either through register config5 or through the ALARM pin.

6. Disable clock divider sync by setting clkdiv_sync_ena to “0” in register config0.

After these steps all the DAC34H84 outputs will be synchronized.

MULTI-DEVICE OPERATION: SINGLE SYNC SOURCE MODE

In Single Sync Source mode, the FIFO write and read pointers are reset from the same sync source, either ISTR

or SYNC. Although the FIFO in this mode can still absorb the data delay differences due to variations in the

digital source output paths or board level wiring it is impossible to guarantee data will be read from the FIFO of

different devices simultaneously thus preventing exact phase alignment.

In Single Sync Source mode the FIFO read pointer reset is handoff between the two clock domains (DATACLK

and FIFO OUT CLOCK) by simply re-sampling the write pointer reset. Since the two clocks are asynchronous

there is a small but distinct possibility of a meta-stablility during the pointer handoff. This meta-stability can cause

the outputs of the multiple devices to slip by up to 2 DAC clock cycles.

When the PLL is enabled with Single Sync Source mode, the FIFO read pointer is not synchronized by the

OSTR signal. Therefore, there is no restriction on the PLL PFD frequency as described in the previous section.

DACCLKP/N

DAB[15:0]P/N

DCD[15:0]P/N

FPGA

DAC34H84 DAC1

ISTRP/N

Delay 1

LVPECL Outputs

DATACLKP/N

Variable delays due to variations in the FPGA(s) output

paths or board level wiring or temperature/voltage deltas

PLL/

DLL

Clock Generator

LVPECL Outputs

0 to 2 DAC Clock Cycles

DAB[15:0]P/N

DCD[15:0]P/N

ISTRP/N

Delay 2

DATACLKP/N

DAC34H84 DAC2

DACCLKP/N

B0456-02

Figure 61. Multi-Device Operation in Single Sync Source Mode

FIR FILTERS

Figure 62 through Figure 65 show the magnitude spectrum response for the FIR0, FIR1, FIR2 and FIR3

interpolating filters where f_INis the input data rate to the FIR filter. Figure 66 to Figure 69 show the composite

filter response for 2x, 4x, 8x and 16x interpolation. The transition band for all interpolation settings is from 0.4 to

0.6 x f_DATA(the input data rate to the device) with < 0.001dB of pass-band ripple and > 90 dB stop-band

attenuation.

The DAC34H84 also has a 9-tap inverse sinc filter (FIR4) that runs at the DAC update rate (f_DAC) that can be

used to flatten the frequency response of the sample-and-hold output. The DAC sample-and-hold output sets the

output current and holds it constant for one DAC clock cycle until the next sample, resulting in the well-known

sin(x)/x or sinc(x) frequency response (Figure 70, red line). The inverse sinc filter response (Figure 70, blue line)

has the opposite frequency response from 0 to 0.4 x Fdac, resulting in the combined response (Figure 70, green

line). Between 0 to 0.4 x f_DAC, the inverse sinc filter compensates the sample-and-hold roll-off with less than 0.03

dB error.

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The inverse sinc filter has a gain > 1 at all frequencies. Therefore, the signal input to FIR4 must be reduced from

full scale to prevent saturation in the filter. The amount of back-off required depends on the signal frequency, and

is set such that at the signal frequencies the combination of the input signal and filter response is less than 1 (0

dB). For example, if the signal input to FIR4 is at 0.25 x f_DAC, the response of FIR4 is 0.9 dB, and the signal must

be backed off from full scale by 0.9 dB to avoid saturation. The gain function in the QMC blocks can be used to

reduce the amplitude of the input signal. The advantage of FIR4 having a positive gain at all frequencies is that

the user is then able to optimize the back-off of the signal based on its frequency.

The filter taps for all digital filters are listed in Table 4. Note that the loss of signal amplitude may result in lower

SNR due to decrease in signal amplitude.

20

0

–20

–40

–60

–80

–100

–120

–140

–160

–100

–120

–140

–160

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

f/f_IN

1

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

f/f_IN

1

G048

G049

Figure 62. Magnitude Spectrum for FIR0

Figure 63. Magnitude Spectrum for FIR1

20

0

–20

–40

–60

–80

–20

–40

–60

–80

–100

–120

–140

–160

–120

–140

–160

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

f/f_IN

1

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

f/f_IN

1

G050

G051

Figure 64. Magnitude Spectrum for FIR2

Figure 65. Magnitude Spectrum for FIR3

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DAC34H84

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20

0

20

0

–20

–40

–60

–80

–100

–120

–140

–160

–100

–120

–140

–160

0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

f/f_DATA

1

0

0.2 0.4 0.6 0.8

1

1.2 1.4 1.6 1.8

2

f/f_DATA

G052

G053

Figure 66. 2x Interpolation Composite Response

Figure 67. 4x Interpolation Composite Response

20

0

–20

–40

–60

–80

–100

–120

–140

–160

–100

–120

–140

–160

0

0.5

1

1.5

2

2.5

3

3.5

4

0

1

2

3

4

5

6

7

8

f/f_DATA

G054

G055

Figure 68. 8x Interpolation Composite Response

Figure 69. 16x Interpolation Composite Response

4

3

2

FIR4

1

Corrected

0

–1

–2

–3

–4

sin(x)/x

0

0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

f/f_DAC

G056

Figure 70. Magnitude Spectrum for Inverse Sinc Filter

Table 7. FIR Filter Coefficients

Non-Interpolating

Inverse-SINC Filter

2x Interpolating Half-band Filters

FIR0

FIR1

FIR2

FIR3

FIR4

59 Taps

23 Taps

11 Taps

9 Taps

6

-12

29

3

1

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Table 7. FIR Filter Coefficients (continued)

Non-Interpolating

Inverse-SINC Filter

2x Interpolating Half-band Filters

FIR0

FIR1

FIR2

FIR3

FIR4

59 Taps

23 Taps

11 Taps

9 Taps

0

-19

0

-19

0

84

0

84

0

-25

0

-25

0

-4

13

-4

13

-214

0

-214

0

-50

47

-336

0

-336

0

1209

2048⁽¹⁾

1209

150

256⁽¹⁾

150

592⁽¹⁾

0

-100

0

-100

0

1006

0

1006

0

192

0

192

0

-2691

0

-2691

0

-342

0

-342

0

10141

16384⁽¹⁾

10141

572

0

572

0

-914

0

-914

0

1409

0

1409

0

-2119

0

-2119

0

3152

0

3152

0

-4729

0

-4729

0

7420

0

7420

0

-13334

0

-13334

0

41527

65536⁽²⁾

41527

(1) Center taps are highlighted in BOLD

(2) Center taps are highlighted in BOLD

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COMPLEX SIGNAL MIXER

The DAC34H84 has two paths of complex signal mixer blocks that contain two full complex mixer (FMIX) blocks

and power saving coarse mixer (CMIX) blocks. The signal path is shown in Figure 71.

16

I Data In

(A)

I Data Out

(A)

Complex

Signal

Multiplier

Fs/2

Mixer

Fs/4

Mixer

16

Q Data In

(B)

Q Data Out

(B)

sine

16

cosine

16

CMIX<1>

CMIX<2> CMIX<0>

CMIX<3>

sine

16

cosine sine

16 16

cosine

16

(AB)

Numerically

Controlled

Oscillator

Fixed Fs/8

Oscillator

NCO_ENA

B0471-02

Note: Channel CD data path not shown

Figure 71. Path of Complex Signal Mixer

FULL COMPLEX MIXER

The two FMIX blocks operate with independent Numerically Controlled Oscillators (NCOs) and enable flexible

frequency placement without imposing additional limitations in the signal bandwidth. The NCOs have 32-bit

frequency registers (phaseaddAB(31:0) and phaseaddCD(31:0)) and 16-bit phase registers (phaseoffsetAB(15:0)

and phaseoffsetCD(15:0)) that generate the sine and cosine terms for the complex mixing. The NCO block

diagram is shown in Figure 72.

32

16

sin

Accumulator

32

16

32

16

Look-Up

Table

Frequency

Register

Σ

16

cos

CLK

RESET

16

f_DAC

Phase

Register

NCO SYNC

via

syncsel_NCO[3:0]

B0026-03

Figure 72. NCO Block Diagram

Synchronization of the NCOs occurs by resetting the NCO accumulators to zero. The synchronization source is

selected by syncsel_NCO(3:0) in config31. The frequency word in the phaseaddAB(31:0) and phaseaddCD(31:0)

registers is added to the accumulators every clock cycle, f_DAC. The output frequency of the NCO is:

freq´ f_{NCO _ CLK}

f_NCO

=

2³²

(1)

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With the complex mixer enabled, the two channels in the mixer path are treated as complex vectors of the form

I_IN(t) + j Q_IN(t). The complex signal multiplier (shown in Figure 73) will multiply the complex channels with the sine

and cosine terms generated by the NCO. The resulting output, I_OUT(t) + j Q_OUT(t), of the complex signal multiplier

is:

I_OUT(t) = (I_IN(t)cos(2πf_NCOt + δ) – Q_IN(t)sin(2πf_NCOt + δ)) × 2^{(mixer_gain – 1)}

Q_OUT(t) = (I_IN(t)sin(2πf_NCOt + δ) + Q_IN(t)cos(2πf_NCOt + δ)) × 2^{(mixer_gain – 1)}

where t is the time since the last resetting of the NCO accumulator, δ is the phase offset value and mixer_gain is

either 0 or 1. δ is given by:

δ = 2π × phase_offsetAB/CD(15:0)/2¹⁶

The mixer_gain option allows the output signals of the multiplier to reduce by half (6dB). See Mixer Gain section

for details.

16

I_OUT(t)

I_IN(t)

16

Q_IN(t)

16

Q_OUT(t)

16

cosine

16

sine

B0472-01

Figure 73. Complex Signal Multiplier

COARSE COMPLEX MIXER

In addition to the full complex mixers, the DAC34H84 also has coarse mixer blocks capable of shifting the input

signal spectrum by the fixed mixing frequencies ±n×f_S/8. Utilizing the coarse mixer instead of the full mixers

lowers power consumption.

The output of the fs/2, fs/4, and –fs/4 mixer block is:

I_OUT(t) = I(t)cos(2πf_CMIXt) – Q(t)sin(2πf_CMIXt)

Q_OUT(t) = I(t)sin(2πf_CMIXt) + Q(t)cos(2πf_CMIXt)

Since the sine and the cosine terms are a function of fs/2, fs/4, or –fs/4 mixing frequencies, the possible resulting

value of the terms will only be 1, -1, or 0. The simplified mathematics allows the complex signal multiplier to be

bypassed in any one of the modes, thus mixer gain is not available. The fs/2, fs/4, and –fs/4 mixer blocks

performs mixing through negating and swapping of I/Q channel on certain sequence of samples. Table 8 shows

the algorithm used for those mixer blocks.

Table 8. Fs/2, Fs/4, and –Fs/4 Mixing Sequence

MODE

MIXING SEQUENCE

Iout = {+I1, +I2, +I3, +I4…}

Qout = {+Q1, +Q2, +Q3, +Q4…}

Normal (mixer bypassed)

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Table 8. Fs/2, Fs/4, and –Fs/4 Mixing Sequence (continued)

MODE

MIXING SEQUENCE

Iout = {+I1, -I2, +I3, -I4…}

Qout = {+Q1, -Q2, +Q3, -Q4…}

Iout = {+I1, -Q2, -I3, +Q4…}

Qout = {+Q1, +I2, -Q3, -I4…}

Iout = {+I1, +Q2, -I3, -Q4…}

Qout = {+Q1, -I2, -Q3, +I4…}

fs/2

fs/4

-fs/4

The fs/8 mixer can be enabled along with various combinations of fs/2, fs/4, and –fs/4 mixer. Since the fs/8 mixer

uses the complex signal multiplier block with fixed fs/8 sine and cosine term, the output of the multiplier is:

I_OUT(t) = (I_IN(t)cos(2πf_NCOt + δ) – Q_IN(t)sin(2πf_NCOt + δ)) × 2^{(mixer_gain – 1)}

Q_OUT(t) = (I_IN(t)sin(2πf_NCOt + δ) + Q_IN(t)cos(2πf_NCOt + δ)) × 2^{(mixer_gain – 1)}

where f_CMIXis the fixed mixing frequency selected by cmix(3:0). The mixing combinations are described in

Table 9. The mixer_gain option allows the output signals of the multiplier to reduce by half (6dB). See Mixer Gain

section for details.

Table 9. Coarse Mixer Combinations

Fs/8 Mixer

cmix(3)

Fs/4 Mixer

cmix(2)

Fs/2 Mixer

cmix(1)

–Fs/4 Mixer

cmix(0)

cmix(3:0)

Mixing Mode

0000

0001

Disabled

Enabled

–

Disabled

Enabled

Disabled

Enabled

–

Disabled

Enabled

Disabled

Enabled

Disabled

Enabled

–

Disabled

Enabled

Disabled

–

No mixing

–Fs/4

0010

Fs/2

0100

+Fs/4

1000

+Fs/8

1010

–3Fs/8

1100

+3Fs/8

1110

–Fs/8

All others

Not recommended

MIXER GAIN

The maximum output amplitude out of the complex signal multiplier (i.e., FMIX mode or CMIX mode with fs/8

mixer enabled) occurs if I_IN(t) and Q_IN(t) are simultaneously full scale amplitude and the sine and cosine

arguments are equal to 2π x f_MIXt + δ (2N-1) x π/4, where N = 1, 2, 3, etc....

sine

cosine

Max output occurs when both

sine and cosine are 0.707

M0221-01

Figure 74. Maximum Output of the Complex Signal Multiplier

With mixer_gain = 1 and both I_IN(t) and Q_IN(t) are simultaneously full scale amplitude, the maximum output

possible out of the complex signal multiplier is 0.707 + 0.707 = 1.414 (or 3dB). This configuration can cause

clipping of the signal and should therefore be used with caution.

With mixer_gain = 0 in config2, the maximum output possible out of the complex signal multiplier is 0.5 x (0.707

+ 0.707) = 0.707 (or -3dB). This loss in signal power is in most cases undesirable, and it is recommended that

the gain function of the QMC block be used to increase the signal by 3 dB to compensate.

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REAL CHANNEL UPCONVERSION

The mixer in the DAC34H84 treats the A, B, C, and D inputs are complex input data and produces a complex

output for most mixing frequencies. The real input data for each channel can be isolated only when the mixing

frequency is set to normal mode or fs/2 mode. Refer to Table 8 for details.

QUADRATURE MODULATION CORRECTION (QMC)

GAIN AND PHASE CORRECTION

The DAC34H84 includes a Quadrature Modulator Correction (QMC) block. The QMC blocks provide a mean for

changing the gain and phase of the complex signals to compensate for any I and Q imbalances present in an

analog quadrature modulator. The block diagram for the QMC block is shown in Figure 75. The QMC block

contains 3 programmable parameters.

Registers qmc_gainA/B(10:0) and qmc_gainC/D(10:0) controls the I and Q path gains and is an 11-bit unsigned

value with a range of 0 to 1.9990 and the default gain is 1.0000. The implied decimal point for the multiplication

is between bit 9 and bit 10.

Register qmc_phaseAB/CD(11:0) control the phase imbalance between I and Q and are a 12-bit values with a

range of –0.5 to approximately 0.49975. The QMC phase term is not a direct phase rotation but a constant that is

multiplied by each "Q" sample then summed into the "I" sample path. This is an approximation of a true phase

rotation in order to keep the implementation simple.

LO feed-through can be minimized by adjusting the DAC offset feature described below.

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qmc_gainA[10:0]

11

16

I Data In

(A)

I Data Out

(A)

Σ

12

qmc_phaseAB[11:0]

16

Q Data In

(B)

Q Data Out

(B)

11

qmc_gainB[10:0]

qmc_gainC[10:0]

11

16

I Data In

(C)

I Data Out

(C)

Σ

12

qmc_phaseCD[11:0]

16

Q Data In

(D)

Q Data Out

(D)

11

qmc_gainD[10:0]

B0164-03

Figure 75. QMC Block Diagram

OFFSET CORRECTION

Registers qmc_offsetA(12:0), qmc_offsetB(12:0), qmc_offsetC(12:0) and qmc_offsetD(12:0) can be used to

independently adjust the DC offsets of each channel. The offset values are in represented in 2s-complement

format with a range from –4096 to 4095.

The offset value adds a digital offset to the digital data before digital-to-analog conversion. Since the offset is

added directly to the data it may be necessary to back off the signal to prevent saturation. Both data and offset

values are LSB aligned.

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qmc_offsetA

{–4096, –4095, ..., 4095}

13

16

A Data In

A Data Out

B Data Out

Σ

B Data In

13

qmc_offsetB

{–4096, –4095, ..., 4095}

qmc_offsetC

{–4096, –4095, ..., 4095}

13

16

C Data In

D Data In

C Data Out

D Data Out

Σ

13

qmc_offsetD

{–4096, –4095, ..., 4095}

B0165-03

Figure 76. Digital Offset Block Diagram

GROUP DELAY CORRECTION

A complex transmitter system typically is consisted of a DAC, reconstruction filter network, and I/Q modulator.

Besides the gain and phase mismatch contribution, there could also be timing mismatch contribution from each

components. For instance, the timing mismatch could come from the PCB trace length variation between the I

and Q channels and the group delay variation from the reconstruction filter.

This timing mismatch in the complex transmitter system creates phase mismatch that varies linearly with respect

to frequency. To compensate for the I/Q imbalances due to this mismatch, the DAC34H84 has group delay

correction block for each DAC channel. Each DAC channel can adjust its delay through grp_delayA(7:0)

grp_delayB(7:0) grp_delayC(7:0) and grp_delayD(7:0) in register config46 and config47. The maximum delay

ranges from 30ps to 100ps and is dependent on DAC sample clock. Contact TI for specific application

information. Refer to the Group Delay vs Step Code plots in the Typical Characteristics section. The group delay

correction, along with gain/phase correction, can be useful for correcting imbalances in wide-band transmitter

system.

TEMPERATURE SENSOR

The DAC34H84 incorporates a temperature sensor block which monitors the temperature by measuring the

voltage across 2 transistors. The voltage is converted to an 8-bit digital word using a successive-approximation

(SAR) analog to digital conversion process. The result is scaled, limited and formatted as a twos complement

value representing the temperature in degrees Celsius.

The sampling is controlled by the serial interface signals SDENB and SCLK. If the temperature sensor is enabled

(tsense_sleep = “0” in register config26) a conversion takes place each time the serial port is written or read. The

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data is only read and sent out by the digital block when the temperature sensor is read in tempdata(7:0) in

config6. The conversion uses the first eight clocks of the serial clock as the capture and conversion clock, the

data is valid on the falling eighth SCLK. The data is then clocked out of the chip on the rising edge of the ninth

SCLK. No other clocks to the chip are necessary for the temperature sensor operation. As a result the

temperature sensor is enabled even when the device is in sleep mode.

In order for the process described above to operate properly, the serial port read from config6 must be done with

an SCLK period of at least 1 μs. If this is not satisfied the temperature sensor accuracy is greatly reduced.

DATA PATTERN CHECKER

The DAC34H84 incorporates a simple pattern checker test in order to determine errors in the data interface. The

main cause of failures is setup/hold timing issues. The test mode is enabled by asserting iotest_ena in register

config1. In test mode the analog outputs are deactivated regardless of the state of TXENA or sif_texnable in

register config3.

The data pattern key used for the test is 8 words long and is specified by the contents of iotest_pattern[0:7] in

registers config37 through config44. The data pattern key can be modified by changing the contents of these

registers.

The first word in the test frame is determined by a rising edge transition in ISTR or SYNC, depending on the

syncsel_fifoin(3:0) setting in config32. At this transition, the pattern0 word should be input to the data DAB[15:0]

pins, and pattern2 should be input to the data DCD[15:0] pins. Patterns 1, 4, and 5 of DAB[15:0] bus and pattern

3, 6, and 7 of DCD[15:0] bus should follow sequentially on each edge of DATACLK (rising and falling). The

sequence should be repeated until the pattern checker test is disabled by setting iotest_ena back to “0”. It is not

necessary to have a rising ISTR or SYNC edge aligned with every four DATACLK cycle, just the first one to mark

the beginning of the series.

Start cycle again with optional rising edge of ISTR or SYNC

Pattern 0 Pattern 1 Pattern 4 Pattern 5 Pattern 0 Pattern 1 Pattern 4 Pattern 5

DAB[15:0]P/N

[15:0]

Pattern 2 Pattern 3 Pattern 6 Pattern 7 Pattern 2 Pattern 3 Pattern 6 Pattern 7

[15:0] [15:0] [15:0] [15:0] [15:0] [15:0] [15:0] [15:0]

DCD[15:0]P/N

DATACLKP/N (DDR)

ISTRP/N

Sync

Option #1

Sync

Option #2

SYNCP/N

T0532-01

Figure 77. IO Pattern Checker Data Transmission Format

The test mode determines if the all the patterns on the two 16-bit LVDS data buses (DAB[15:0]P/N and

DCD[15:0]P/N) were received correctly by comparing the received data against the data pattern key. If any bits in

either of the two 16-bit data buses were received incorrectly, the corresponding bits in iotest_results(15:0) in

register config4 will be set to “1” to indicate bit error location. The user can check the corresponding bit location

on both 16-bit data buses and implement the fix accordingly. Furthermore, the error condition will trigger the

alarm_from_iotest bit in register config5 to indicate a general error in the data interface. When data pattern

checker mode is enabled, this alarm in register config5, bit7 is the only valid alarm. Other alarms in register

config5 are not valid and can be disregarded.

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For instance, pattern0 is programmed to the default of 0x7A7A. If the received Pattern 0 is 0x7A7B, then bit 0 in

iotest_results(15:0) will be set to “1” to indicate an error in bit 0 location. The alarm_from_iotest will also be set to

“1” to report the data transfer error. Note that iotest_results(15:0) does not indicate which of the 16-bit buses has

the error. The user needs to check both 16-bit buses and then narrow down the error from the bit location

information.

The alarms can be cleared by writing 0x0000 to iotest_results(15:0) and “0” to alarm_from_iotest through the

serial interface. The serial interface will read back 0s if there are no errors or if the errors are cleared. The

corresponding alarm bit will remain a “1” if the errors remain.

It is recommended to enable the pattern checker and then run the pattern sequence for 100 or more complete

cycles before clearing the iotest_results(15:0) and alarm_from_iotest. This will eliminate the possibility of false

alarms generated during the setup sequence.

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PARITY CHECK TEST

The DAC34H84 has a parity check test that enables continuous validity monitoring of the data received by the

DAC. Parity check testing in combination with the data pattern checker offer an excellent solution for detecting

board assembly issues due to missing pad connections.

For the parity check test, an extra parity bit is added to the data bits to ensure that the total number of set bits

(bits with value 1) is even or odd. This simple scheme is used to detect single or any other odd number of data

transfer errors. Parity testing is implemented in the DAC34H84 in two ways: 32-bit parity and dual 16-bit parity.

32-BIT PARITY

In the 32-bit mode the additional parity bit is sourced to the parity input (PARITYP/N) for the 32-bit data transfer

into the DAB[15:0]P/N and DCD[15:0]P/N inputs. This mode is enabled by setting the single_parity_ena bit in

register config1. The input parity value is defined to be the total number of logic 1s on the 33-bit data bus – the

DAB[15:0]P/N inputs, the DCD[15:0]P/N inputs, and the PARITYP/N input. This value, the total number of logic

1s, must match the parity test selected in the oddeven_parity bit in register config1.

For example, if the oddeven_parity bit is set to “1” for odd parity, then the number of 1s on the 33-bit data bus

should be odd. The DAC will check the data transfer through the parity input. If the data received has odd

number of 1s, then the parity is correct. If the data received has even number of 1s, then the parity is incorrect.

The corresponding alarm for parity error will be set accordingly.

Figure 79 shows the simple XOR structure used to check word parity. Parity is tested independently for data

captured on both rising and falling edges of DATACLK (alarm_Aparity and alarm_Bparity, respectively). Testing

on both edges helps in determining a possible setup/hold issue. Both alarms are captured individually in register

config5.

PARITY

DAB[15:0]

DCD[15:0]

alarm_Aparity

oddeven_parity

alarm_Bparity

Parity Block

DATACLK

B0458-02

Figure 79. DAC34H84 32-Bit Parity Check

DUAL 16-BIT PARITY

In the dual 16-bit mode, each 16-bit LVDS data bus input will be accompanied by a parity bit for error checking.

The DAB[15:0]P/N and ISTRP/N are one 17-bit data path, and the DCD[15:0]P/N and PARITYP/N are another

path. This mode is enabled by setting the dual_parity_ena bit in register config1. The input parity value is defined

to be the total number of logic 1s on each 17-bit data bus. This value, the total number of logic 1s, must match

the parity test selected in the oddeven_parity bit in register config1.

For example, if the oddeven_parity bit is set to “1” for odd parity, then the number of 1s on each 17-bit data bus

should be odd. The DAC will check the data transfer through the parity input. If the data received has odd

number of 1s, then the parity is correct. If the data received has even number of 1s, then the parity is incorrect.

The corresponding alarm for parity error will be set accordingly.

Figure 80 shows the simple XOR structure used to check word parity. Parity is tested independently for data

captured on both rising and falling edges of DATACLK for each data path (alarm_Aparity, alarm_Bparity,

alarm_Cparity, and alarm_Dparity, respectively). Testing on both edges and both data buses helps in

determining a possible setup/hold issue. All of the alarms are captured individually in register config5.

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In this mode the ISTR signal functions as a parity signal and cannot be used to sync the FIFO pointer

simultaneously. It is recommended to use the SYNC to sync the FIFO pointer. If ISTR has to be used to sync the

FIFO pointer, the ISTR sync can only be possible upon start-up when dual 16-bit parity function is disabled.

Once the initialization is finished, disable the FIFO pointer sync through ISTR (by configuring syncsel_fifoin and

syncsel_fifoout in config32) and enable the dual 16-bit parity function afterwards.

alarm_Aparity

ISTR

oddeven_parity

DAB[15:0]

alarm_Bparity

Parity Block

DATACLK

alarm_Cparity

PARITY

oddeven_parity

DCD[15:0]

alarm_Dparity

Parity Block

DATACLK

B0463-01

Figure 80. DAC34H84 Dual 16-Bit Parity Check

DAC34H84 ALARM MONITORING

The DAC34H84 includes a flexible set of alarm monitoring that can be used to alert of a possible malfunction

scenario. All the alarm events can be accessed either through the config5 register or through the ALARM pin.

Once an alarm is set, the corresponding alarm bit in register config5 must be reset through the serial interface to

allow further testing. The set of alarms includes the following conditions:

Zero check alarm

•

Alarm_from_zerochk. Occurs when the FIFO write pointer has an all zeros pattern. Since the write pointer is a

shift register, all zeros will cause the input point to be stuck until the next sync event. When this happens a

sync to the FIFO block is required.

FIFO alarms

alarm_from_fifo. Occurs when there is a collision in the FIFO pointers or a collision event is close.

•

–

alarm_fifo_2away. Pointers are within two addresses of each other.

alarm_fifo_1away. Pointers are within one address of each other.

alarm_fifo_collision. Pointers are equal to each other.

Clock alarms

clock_gone. Occurs when either the DACCLK or DATACLOCK have been stopped.

•

–

alarm_dacclk_gone. Occurs when the DACCLK has been stopped.

alarm_dataclk_gone. Occurs when the DATACLK has been stopped.

Pattern checker alarm

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•

alarm_from_iotest. Occurs when the input data pattern does not match the pattern key.

PLL alarm

•

alarm_from_pll. Occurs when the PLL is out of lock.

Parity alarms

•

alarm_Aparity: In dual parity mode, alarm indicating a parity error on the A word. In single parity mode, alarm

on the 32-bit data captured on the rising edge of DATACLKP/N.

•

alarm_Bparity: In dual parity mode, alarm indicating a parity error on the B word. In single parity mode, alarm

on the 32-bit data captured on the falling edge of DATACLKP/N.

•

alarm_Cparity: In dual parity mode, alarm indicating a parity error on the C word.

alarm_Dparity: In dual parity mode, alarm indicating a parity error on the D word.

To prevent unexpected DAC outputs from propagating into the transmit channel chain, the clock and alarm_

fifo_collision alarms can be set in config2 to shut-off the DAC output automatically regardless of the state of

TXENA or sif_txenable.

Alarm monitoring is implemented as follows:

•

Power up the device using the recommended power-up sequence.

Clear all the alarms in config5 by setting them to zeros.

Unmask those alarms that will generate a hardware interrupt through the ALARM pin in config7.

Enable automatic DAC shut-off in register config2 if required.

In the case of an alarm event, the ALARM pin will trigger. If automatic DAC shut-off has been enabled the

DAC outputs will be disabled.

•

Read registers config5 to determine which alarm triggered the ALARM pin.

Correct the error condition and re-synchronize the FIFO.

Clear the alarms in config5.

Re-read config5 to ensure the alarm event has been corrected.

Keep clearing and reading config5 until no error is reported.

POWER-UP SEQUENCE

The following startup sequence is recommended to power-up the DAC34H84:

1. Set TXENA low

2. Supply all 1.2V voltages (DACVDD, DIGVDD, CLKVDD and VFUSE) and all 3.3V voltages (AVDD, IOVDD,

and PLLAVDD). The 1.2V and 3.3V supplies can be powered up simultaneously or in any order. There are

no specific requirements on the ramp rate for the supplies.

3. Provide all LVPECL inputs: DACCLKP/N and the optional OSTRP/N. These inputs can also be provided after

the SIF register programming.

4. Toggle the RESETB pin for a minimum 25 ns active low pulse width.

5. Program the SIF registers.

6. Program fuse_sleep (config27, bit<11>) to put the internal fuses to sleep.

7. FIFO configuration needed for synchronization:

(a) Program syncsel_fifoin(3:0) (config32, bit<15:12>) to select the FIFO input pointer sync source.

(b) Program syncsel_fifoout(3:0) (config32, bit<11:8>) to select the FIFO output pointer sync source.

(c) Program syncsel_fifo_input(1:0) (config31, bit<3:2>) to select the FIFO input sync source.

8. Clock divider configuration needed for synchronization:

(a) Program clkdiv_sync_sel (config32, bit<0>) to select the clock divider sync source.

(b) Program clkdiv_sync_ena (config0, bit<2>) to "1" to enable clock divider sync.

(c) For multi-DAC synchronization in PLL mode, program pll_ndivsync_ena (config24, bit<11>) to “1” to

synchronize the PLL N-divider.

9. Provide all LVDS inputs (D[15:0]P/N, DCD[15:0]P/N, DATACLKP/N, ISTRP/N, SYNCP/N and PARITYP/N)

simultaneously. Synchronize the FIFO and clock divider by providing the pulse or periodic signals needed.

(a) For Single Sync Source Mode where either ISTRP/N or SYNCP/N is used to sync the FIFO, a single

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rising edge for FIFO and clock divider sync is recommended. Periodic sync signal is not recommended

due to the non-deterministic latency of the sync signal through the clock domain transfer.

(b) For Dual Sync Sources Mode, both single pulse or periodic sync signals can be used.

(c) For multi-DAC synchronization in PLL mode, the LVDS SYNCP/N signal is used to sync the PLL

N-divider and can be sourced from either the FPGA/ASIC pattern generator or clock distribution circuit as

long as the t_{(SYNC_PLL)}setup and hold timing requirement is met with respect to the reference clock

source at DACCLKP/N pins. The LVDS SYNCP/N signal can be provided at this point.

10. FIFO and clock divider configurations after all the sync signals have provided the initial sync pulses needed

for synchronization:

(a) For Single Sync Source Mode where the clock divider sync source is either ISTRP/N or SYNCP/N, clock

divider syncing must be disabled after DAC34H84 initialization and before the data transmission by

setting clkdiv_sync_ena (config0, bit 2) to “0”.

(b) For Dual Sync Sources Mode, where the clock divider sync source is from the OSTR signal (either from

external OSTRP/N or internal PLL N divider output), the clock divider syncing may be enabled at all time.

(c) Optionally, to prevent accidental syncing of the FIFO when sending the ISTRP/N or SYNCP/N pulse to

other digital blocks such as NCO, QMC, etc, disable FIFO syncing by setting syncsel_fifoin(3:0) and

syncsel_fifoout(3:0) to “0000” after the FIFO input and output pointers are initialized. If the FIFO and

sync remain enabled after initialization, the ISTRP/N or SYNCP/N pulse must occur in ways to not

disturb the FIFO operation. Refer to the INPUT FIFO section for detail.

(d) Disable PLL N-divider syncing by setting pll_ndivsync_ena (config24, bit<11>) to "0".

11. Enable transmit of data by asserting the TXENA pin or set sif_txenable to “1”.

12. At any time, if any of the clocks (i.e DATACLK or DACCLK) is lost or a FIFO collision alarm is detected, a

complete resynchronization of the DAC is necessary. Set TXENABLE low and repeat steps 7 through 11.

Program the FIFO configuration and clock divider configuration per steps 7 and 8 appropriately to accept the

new sync pulse or pulses for the synchronization.

EXAMPLE START-UP ROUTINE

DEVICE CONFIGURATION

f_DATA= 614.4MSPS

Interpolation = 2x

Input data = baseband data

f_OUT= 122.88MHz

PLL = Enabled

Full Mixer = Enabled

Dual Sync Sources Mode

PLL CONFIGURATION

f_REFCLK= 614.4MHz at the DACCLKP/N LVPECL pins

f_DACCLK= f_DATAx Interpolation = 1228.8MHz

f_VCO= 3 x f_DACCLK= 3686.4MHz (keep f_VCObetween 3.3GHz to 4GHz)

PFD = f_OSTR= 38.4MHz

N = 16, M = 32, P = 3, single charge pump

pll_vco(5:0) = “100100” (36)

NCO CONFIGURATION

f_NCO= 122.88MHz

f_{NCO_CLK}= 1228.8MHz

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freq = f_CNOx 2^32 / 1228.8 = 429496730 = 0x1999999A

phaseaddAB(31:0) or phaseaddCD(31:0) = 0x19999999A

NCO SYNC = sif_sync

EXAMPLE START-UP SEQUENCE

Table 10. Example Start-Up Sequence Description

STEP

READ/WRITE

ADDRESS

N/A

VALUE

N/A

DESCRIPTION

1

2

3

4

N/A

Set TXENA Low

N/A

Power-up the device

Apply LVPECL DACCLKP/N for PLL reference clock

Toggle RESETB pin

QMC offset and correction enabled, 2x int, FIFO enabled, Alarm enabled,

clock divider sync enabled, inverse sinc filter enabled.

5

6

7

Write

0x00

0x01

0x02

0xF19F

0x040E

0x7052

Single parity enabled, FIFO alarms enabled (2 away, 1 away, and collision).

Output shut-off when DACCLK gone, DATACLK gone, and FIFO collision.

Mixer block with NCO enabled, twos complement.

Output current set to 20mAFS with internal reference and 1.28kohm R_BIAS

resistor.

8

9

Write

0x03

0x07

0xA000

0xD8FF

Un-mask FIFO collision, DACCLK-gone, and DATACLK-gone alarms to the

Alarm output.

Program the desired channel A QMC offset value. (Causes Auto-Sync for

QMC AB-Channels Offset Block)

10

11

12

Write

0x08

0x09

0x0A

N/A

Program the desired FIFO offset value and channel B QMC offset value.

Program the desired channel C QMC offset value. (Causes Auto-Sync for

QMC CD-Channels Offset Block)

13

14

Write

0x0B

0x0C

N/A

Program the desired channel D QMC offset value.

Program the desired channel A QMC gain value.

Coarse mixer mode not used. Program the desired channel B QMC gain

value.

15

Write

0x0D

N/A

16

17

Write

0x0E

0x0F

N/A

Program the desired channel B QMC gain value.

Program the desired channel C QMC gain value.

Program the desired channel AB QMC phase value. (Causes Auto-Sync

QMC AB-Channels Correction Block)

18

19

20

21

Write

0x10

0x11

0x12

0x13

N/A

Program the desired channel CD QMC phase value. (Causes Auto-Sync for

the QMC CD-Channels Correction Block)

Program the desired channel AB NCO phase offset value. (Causes

Auto-Sync for Channel AB NCO Mixer)

Program the desired channel CD NCO phase offset value. (Causes

Auto-Sync for Channel CD NCO Mixer)

22

23

24

25

Write

0x14

0x15

0x16

0x17

0x999A

0x1999

0x999A

0x1999

Program the desired channel AB NCO frequency value

Program the desired channel CD NCO frequency value

PLL enabled, PLL N-dividers sync enabled, single charge pump, prescaler =

3.

26

Write

0x18

0x2C58

27

28

29

Write

0x19

0x1A

0x1B

0x20F4

0x9000

0x0800

M = 32, N = 16, PLL VCO bias tune = “01”

PLL VCO coarse tune = 36

Internal reference

QMC offset AB, QMC offset CD, QMC correction AB, and QMC correction

CD can be synced by sif_sync or auto-sync from register write

30

31

Write

0x1E

0x1F

0x9999

0x4440

Mixer AB and CD values synced by SYNCP/N. NCO accumulator synced by

SYNCP/N.

68

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

Table 10. Example Start-Up Sequence Description (continued)

STEP

READ/WRITE

ADDRESS

VALUE

DESCRIPTION

FIFO Input Pointer Sync Source = ISTR FIFO Output Pointer Sync Source =

OSTR (from PLL N-divider output) Clock Divider Sync Source = OSTR

32

Write

0x20

0x2400

Provide all the LVDS DATA and DATACLK Provide rising edge FRAMEP/N

and rising edge SYNCP/N to sync the FIFO input pointer and PLL

N-dividers.

33

N/A

Read back pll_lfvolt(2:0). If the value is not optimal, adjust pll_vco(5:0) in

0x1A.

34

35

Read

Write

0x18

0x05

N/A

0x0000

Clear all alarms in 0x05.

Read back all alarms in 0x05. Check for PLL lock, FIFO collision,

DACCLK-gone, DATACLK-gone, etc. Fix the error appropriately. Repeat

step 34 and 35 as necessary.

36

Read

0x05

N/A

Sync all the QMC blocks using sif_sync. These blocks can also be synced

via auto-sync through appropriate register writes.

37

Write

0x1F

0x4442

38

39

40

41

42

Write

N/A

0x00

0x1F

0x20

0x18

N/A

0xF19B

0x4448

0x0000

0x2458

N/A

Disable clock divider sync.

Set sif_sync to “0” for the next sif_sync event.

Disable FIFO input and output pointer sync.

Disable PLL N-dividers sync.

Set TXENA high. Enable data transmission.

69

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

LVPECL INPUTS

Figure 81 shows an equivalent circuit for the DAC input clock (DACCLKP/N) and the output strobe clock

(OSTRP/N).

CLKVDD

250 Ω

2 kΩ

DACCLKP

OSTRP

DACCLKN

OSTRN

Internal

Digital In

250 Ω

SLEEP

GND

S0515-01

Figure 81. DACCLKP/N and OSTRP/N Equivalent Input Circuit

Figure 82 shows the preferred configuration for driving the CLKIN/CLKINC input clock with a differential

ECL/PECL source.

C_AC

0.1 μF

+

CLKIN

Differential

ECL

C_AC

or

100 Ω

0.1 μF

(LV)PECL

Source

–

CLKINC

R_T

150 Ω

S0029-02

Figure 82. Preferred Clock Input Configuration with a Differential ECL/PECL Clock Source

70

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

LVDS INPUTS

The DAB[15:0]P/N, DCD[15:0]P/N, DATACLKP/N, SYNCP/N, PARITYP/N, and ISTRP/N LVDS pairs have the

input configuration shown in Figure 83. Figure 84 shows the typical input levels and common-move voltage used

to drive these inputs.

IOVDD

LVDS

Receiver

Internal Digital In

100 Ω

GND

S0516-01

Figure 83. DAB[15:0]P/N, DCD[15:0]P/N, DATACLKP/N, ISTRP/N, SYNCP/N and PARITYP/N LVDS Input

Configuration

Example

V_A

V_B

1.4 V

1 V

DAC34H84

LVDS

Receiver

V_{A, B}

100 Ω

400 mV

0 V

V_{A, B}

V_A

V_COM= (V_A+ V_B)/2

–400 mV

V_B

GND

1

0

Logical Bit

Equivalent

B0459-02

Figure 84. LVDS Data Input Levels

Table 11. Example LVDS Data Input Levels

Resulting Differential

Voltage

Resulting Common-Mode

Voltage

Applied Voltages

Logical Bit Binary

Equivalent

V_A

V_B

V_A,B

V_COM

1.4 V

1.0 V

1.2 V

0.8 V

1.0 V

1.4 V

0.8 V

1.2 V

400 mV

-400 mV

400 mV

-400 mV

1

0

1

0

1.2 V

1.0 V

71

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

CMOS DIGITAL INPUTS

Figure 85 shows a schematic of the equivalent CMOS digital inputs of the DAC34H84. SDIO, SCLK, SLEEP and

TXENA have pull-down resistors while SDENB and RESETB have pull-up resistors internal to the DAC34H84. All

the CMOS digital inputs and outputs are referred to the IOVDD2 supply, which can vary from 1.8V to 3.3V. This

facilitates the I/O interface and eliminates the need of level translation. See the specification table for logic

thresholds. The pull-up and pull-down circuitry is approximately equivalent to 100kΩ.

IOVDD2

100 kΩ

SDIO

SCLK

SLEEP

TXENA

400 Ω

Internal

Digital In

Internal

Digital In

SDENB

RESETB

100 kΩ

GND

S0027-04

Figure 85. CMOS Digital Equivalent Input

REFERENCE OPERATION

The DAC34H84 uses a bandgap reference and control amplifier for biasing the full-scale output current. The

full-scale output current is set by applying an external resistor R_BIASto pin BIASJ. The bias current I_BIASthrough

resistor R_BIASis defined by the on-chip bandgap reference voltage and control amplifier. The default full-scale

output current equals 64 times this bias current and can thus be expressed as:

IOUT_FS= 64 x I_BIAS= 64 x (V_EXTIO/ R_BIAS) / 2

The DAC34H84 has a 4-bit coarse gain control coarse_dac(3:0) in the config3 register. Using gain control, the

IOUT_FScan be expressed as:

IOUT_FS= (coarse_dac + 1)/16 x I_BIASx 64 = (coarse_dac + 1)/16 x (VEXTIO / RBIAS) / 2 x 64

where V_EXTIOis the voltage at terminal EXTIO. The bandgap reference voltage delivers an accurate voltage of

1.2V. This reference is active when extref_ena = ‘0’ in config27. An external decoupling capacitor C_EXTof 0.1 µF

should be connected externally to terminal EXTIO for compensation. The bandgap reference can additionally be

used for external reference operation. In that case, an external buffer with high impedance input should be

applied in order to limit the bandgap load current to a maximum of 100 nA. The internal reference can be

disabled and overridden by an external reference by setting the extref_ena control bit. Capacitor C_EXTmay hence

be omitted. Terminal EXTIO thus serves as either input or output node.

The full-scale output current can be adjusted from 30 mA down to 10 mA by varying resistor R_BIAS, programming

coarse_dac(3:0), or changing the externally applied reference voltage.

NOTE

With internal reference, the minimum Rbias resistor value is 1.28kΩ. Resistor value below

1.28kΩ is not recommended sice it will program the full-scale current to go above 30mA

and potentially damages the device.

DAC TRANSFER FUNCTION

The CMOS DACs consist of a segmented array of PMOS current sources, capable of sourcing a full-scale output

current up to 30 mA. Differential current switches direct the current to either one of the complementary output

nodes IOUTP or IOUTN. Complementary output currents enable differential operation, thus canceling out

common mode noise sources (digital feed-through, on-chip and PCB noise), dc offsets, even order distortion

components, and increasing signal output power by a factor of two.

72

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

The full-scale output current is set using external resistor R_BIASin combination with an on-chip bandgap voltage

reference source (+1.2 V) and control amplifier. Current I_BIASthrough resistor R_BIASis mirrored internally to

provide a maximum full-scale output current equal to 64 times I_BIAS

The relation between IOUTP and IOUTN can be expressed as:

IOUT_FS= IOUTP + IOUTN

.

We will denote current flowing into a node as – current and current flowing out of a node as + current. Since the

output stage is a current source the current flows from the IOUTP and IOUTN pins. The output current flow in

each pin driving a resistive load can be expressed as:

IOUTP = IOUT_FSx CODE / 65536

IOUTN = IOUT_FSx (65535 – CODE) / 65536

where CODE is the decimal representation of the DAC data input word

For the case where IOUTP and IOUTN drive resistor loads R_Ldirectly, this translates into single ended voltages

at IOUTP and IOUTN:

VOUTP = IOUT1 x R_L

VOUTN = IOUT2 x R_L

Assuming that the data is full scale (65535 in offset binary notation) and the R_Lis 25 Ω, the differential voltage

between pins IOUTP and IOUTN can be expressed as:

VOUTP = 20mA x 25 Ω = 0.5 V

VOUTN = 0mA x 25 Ω = 0 V

VDIFF = VOUTP – VOUTN = 0.5V

Note that care should be taken not to exceed the compliance voltages at node IOUTP and IOUTN, which would

lead to increased signal distortion.

ANALOG CURRENT OUTPUTS

The DAC34H84 can be easily configured to drive a doubly terminated 50 Ω cable using a properly selected RF

transformer. Figure 86 and Figure 87 show the 50 Ω doubly terminated transformer configuration with 1:1 and 4:1

impedance ratio, respectively. Note that the center tap of the primary input of the transformer has to be grounded

to enable a DC current flow. Applying a 20 mA full-scale output current would lead to a 0.5 Vpp for a 1:1

transformer and a 1 Vpp output for a 4:1 transformer. The low dc-impedance between IOUTP or IOUTN and the

transformer center tap sets the center of the ac-signal to GND, so the 1 Vpp output for the 4:1 transformer

results in an output between –0.5 V and +0.5 V.

50 Ω

1:1

IOUTP

R_LOAD

50 Ω

100 Ω

AGND

IOUTN

50 Ω

S0517-01

Figure 86. Driving a Doubly Terminated 50 Ω Cable Using a 1:1 Impedance Ratio Transformer

73

DAC34H84

SLAS751A –MARCH 2011–REVISED JUNE 2011

www.ti.com

100 Ω

4:1

IOUTP

IOUTN

R_LOAD

50 Ω

AGND

100 Ω

S0518-01

Figure 87. Driving a Doubly Terminated 50 Ω Cable Using a 4:1 Impedance Ratio Transformer

PACKAGE OPTION ADDENDUM

ORDERABLE

DEVICE

PACKAGE

TYPE

PACKAGE

QUANTITY

LEAD/BALL

FINISH

MSL PEAK

TEMPERATURE

STATUS

Active

PINS

196

ECO PLAN

Green (RoHS & no

DAC34H84IZAY

DAC34H84IZAYR

NFBGA

800

SNAGCU

MSL3 260C

Sb/Br)

Green (RoHS & no

Active

196

1000

Sb/Br)

74

DAC34H84

www.ti.com

SLAS751A –MARCH 2011–REVISED JUNE 2011

REVISION HISTORY

Changes from Original (March 2011) to Revision A

Page

•

Changed from PRODUCT PREVIEW to PRODUCTION DATA ........................................................................................... 1

75

PACKAGE MATERIALS INFORMATION

www.ti.com

27-Jun-2011

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device

Package Package Pins

Type Drawing

SPQ

Reel

A0

B0

K0

P1

W

Pin1

Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant

(mm) W1 (mm)

DAC34H84IZAYR

NFBGA

ZAY

196

1000

330.0

24.4

12.35 12.35

2.3

16.0

24.0

Q1

Pack Materials-Page 1

PACKAGE MATERIALS INFORMATION

www.ti.com

27-Jun-2011

*All dimensions are nominal

Device

Package Type Package Drawing Pins

NFBGA ZAY 196

SPQ

Length (mm) Width (mm) Height (mm)

341.0 345.9 41.3

DAC34H84IZAYR

1000

Pack Materials-Page 2

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型号：	DAC34H84_14
厂家：	TEXAS INSTRUMENTS
描述：	Quad-Channel, 16-Bit, 1.25 GSPS Digital-to-Analog Converter (DAC)
文件：	总80页 (文件大小：1306K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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