ADS5525_14 [TI]
12-BIT, 170 MSPS ADC WITH DDR LVDS/CMOS OUTPUTS;型号: | ADS5525_14 |
厂家: | TEXAS INSTRUMENTS |
描述: | 12-BIT, 170 MSPS ADC WITH DDR LVDS/CMOS OUTPUTS 双倍数据速率 输出元件 |
文件: | 总48页 (文件大小:807K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
ADS5525
www.ti.com
SLWS191–JULY 2006
12-BIT, 170 MSPS ADC WITH DDR LVDS/CMOS OUTPUTS
•
•
•
•
•
•
Power Amplifier Linearization
802.16d/e
Test and Measurement Instrumentation
High Definition Video
Medical Imaging
FEATURES
•
•
•
•
•
•
•
•
Maximum Sample Rate: 170 MSPS
12-Bit Resolution
No Missing Codes
Total Power Dissipation 1.1 W
Internal Sample and Hold
69.5-dBFS SNR at 70-MHz IF
82-dBc SFDR at 70-MHz IF, 0 dB gain
Radar Systems
DESCRIPTION
ADS5525 is a high performance 12-bit, 170-MSPS
A/D converter. It offers state-of-the art functionality
and performance using advanced techniques to
minimize board space. Using an internal sample and
hold and low jitter clock buffer, the ADC supports
both high SNR and high SFDR at high input
frequencies. It features programmable gain options
that can be used to improve SFDR performance at
lower full-scale analog input ranges.
Double Data Rate (DDR) LVDS and Parallel
CMOS Output Options
•
•
•
Programmable Gain up to 6 dB for SNR/SFDR
Trade-Off at High IF
Reduced Power Modes at Lower Sample
Rates
Supports input clock amplitude down to 400
mVPP
In a compact 48-pin QFN, the device offers fully
differential LVDS DDR (Double Data Rate) interface
while parallel CMOS outputs can also be selected.
Flexible output clock position programmability is
available to ease capture and trade-off setup for hold
times. At lower sampling rates, the ADC can be
operated at scaled down power with no loss in
performance. ADS5525 includes an internal
reference, while eliminating the traditional reference
pins and associated external decoupling. The device
also supports an external reference mode.
•
•
•
•
Clock Duty Cycle Stabilizer
No External Reference Decoupling Required
Internal and External Reference Support
Programmable Output Clock position to ease
data capture
•
•
3.3-V Analog and Digital Supply
48-QFN Package (7 mm × 7 mm)
APPLICATIONS
•
•
The device is specified over the industrial
temperature range (-40°C to 85°C).
Wireless Communications Infrastructure
Software Defined Radio
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.
PRODUCT PREVIEW information concerns products in the
formative or design phase of development. Characteristic data and
other specifications are design goals. Texas Instruments reserves
the right to change or discontinue these products without notice.
Copyright © 2006, Texas Instruments Incorporated
ADS5525
www.ti.com
SLWS191–JULY 2006
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be
more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
CLKP
CLKOUTP
CLKOUTM
CLOCKGEN
CLKM
D0_D1_P
D0_D1_M
D2_D3_P
D2_D3_M
D4_D5_P
D4_D5_M
Digital
Encoder
and
INP
INM
12-Bit
ADC
D6_D7_P
D6_D7_M
SHA
Serializer
D8_D9_P
D8_D9_M
D10_D11_P
D10_D11_M
Control
Interface
VCM
Reference
OVR
ADS5525
LVDS MODE
PACKAGE/ORDERING INFORMATION(1)
SPECIFIED
TEMPERATURE
RANGE
TRANSPORT
MEDIA,
QUANTITY
PACKAGE-
LEAD
PACKAGE
DESIGNATOR
PACKAGE
MARKING
ORDERING
NUMBER
PRODUCT
Tape and Reel,
250
ADS5525IRGZT
ADS5525IRGZR
ADS5525
QFN-48(2)
RGZ
–40°C to 85°C
AZ5525
Tape and Reel,
2500
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
Web site at www.ti.com.
(2) For thermal pad size on the package, see the mechanical drawings at the end of this data sheet. θJA = 25.41°C/W (0 LFM air flow), θJC
= 16.5°C/W when used with 2 oz. copper trace and pad soldered directly to a JEDEC standard four layer 3 in x 3 in PCB.
2
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
ABSOLUTE MAXIMUM RATINGS(1)
over operating free-air temperature range (unless otherwise noted)
VALUE
–0.3 V to 3.9
–0.3 V to 3.9
-0.3 to 0.3
-0.3 to 3.3
-0.3 to 1.8
UNIT
Supply voltage range, AVDD
V
V
V
V
V
Supply voltage range, DRVDD
Voltage between AGND and DRGND
Voltage between AVDD to DRVDD
Voltage applied to VCM pin (in external reference mode)
Voltage applied to analog input pins, INP and INM
Voltage applied to input clock pins, CLKP and CLKM
–0.3 V to minimum (3.6, AVDD + 0.3 V)
V
-0.3 V to AVDD + 0.3 V
–40 to 85
V
TA
Operating free-air temperature range
Operating junction temperature range
Storage temperature range
°C
°C
°C
TJ
125
Tstg
–65 to 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 the device at 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.
RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range (unless otherwise noted)
MIN
TYP
MAX
UNIT
SUPPLIES
Analog supply voltage, AVDD
Digital supply voltage, DRVDD
ANALOG INPUTS
3
3
3.3
3.3
3.6
3.6
V
V
Differential input voltage range
2
1.5 ±0.1
1.5
VPP
V
Input common-mode voltage
Voltage applied on VCM in external reference mode
1.45
1
1.55
170
V
CLOCK INPUT
Input clock sample rate
MSPS
Input clock amplitude differential (V(CLKP) - V(CLKM)
)
Sine wave, ac-coupled
0.4
1.5
1.6
VPP
VPP
VPP
V
LVPECL, ac-coupled
LVDS, ac-coupled
0.7
LVCMOS, single-ended, ac-coupled
Input clock duty cycle (See Figure 34)
3.3
35%
–40
50%
65%
DIGITAL OUTPUTS
Maximum external load capacitance from each output pin to DRGND (LVDS and
CMOS modes)
CL
RL
5
pF
Differential load resistance between the LVDS output pairs (LVDS mode)
Operating free-air temperature
100
Ω
85
°C
3
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
ELECTRICAL CHARACTERISTICS
Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C,
AVDD = DRVDD = 3.3 V, sampling rate = 170 MSPS, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock
duty cycle, –1 dBFS differential analog input, internal reference mode, 0dB gain, DDR LVDS data output (unless otherwise
noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
RESOLUTION
12
bits
ANALOG INPUT
Differential input voltage range
Differential input capacitance
Analog input bandwidth
2
7
VPP
pF
–3 dB, source impedance 50 Ω
500
MHz
Analog input common mode current
(per input pin)
280
µA
REFERENCE VOLTAGES
V(REFB)
V(REFT)
VCM
Internal reference bottom voltage
Internal reference top voltage
Common mode output voltage
VCM output current capability
Internal reference mode
Internal reference mode
Internal reference mode
Internal reference mode
0.5
2.5
1.5
±4
V
V
V
mA
DC ACCURACY
No Missing Codes
Specified
0.5
DNL
INL
Differential non-linearity
Integral non-linearity
Offset error
–0.9
TBD
LSB
LSB
± 1
5
mV
Offset temperature coefficient
Gain error
0.002
±1
ppm/°C
%FS
Gain temperature coefficient
DC Power supply rejection ratio
0.01
0.6
∆%/°C
mV/V
PSRR
POWER SUPPLY
I(AVDD)
I(DRVDD)
ICC
Analog supply current
284
49
mA
mA
LVDS mode, IO = 3.5 mA,
RL = 100 Ω, CL = 5 pF
Digital supply current
CMOS mode, FIN = 2.5 MHz,
CL = 5 pF
39
mA
Total supply current
LVDS mode
LVDS mode
333
1.1
mA
W
Total power dissipation
TBD
TBD
TBD
In STANDBY mode with clock
running
Standby power
100
100
mW
mW
Clock stop power
With input clock stopped
4
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
ELECTRICAL CHARACTERISTICS
Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C,
AVDD = DRVDD = 3.3 V, sampling rate = 170 MSPS, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock
duty cycle, –1 dBFS differential analog input, internal reference mode, 0dB gain, DDR LVDS data output (unless otherwise
noted)
PARAMETER
AC CHARACTERISTICS
TEST CONDITIONS
MIN
TYP
MAX
UNIT
FIN = 10 MHz
FIN = 40 MHz
FIN = 70 MHz
FIN = 100 MHz
FIN = 150 MHz
70
69.7
69.5
69.2
68.7
67
TBD
SNR
Signal to noise ratio
dBFS
LSB
dBc
0 dB gain, 2 VPP FS(1)
FIN = 225 MHz
FIN = 300 MHz
3 dB gain, 1.4 VPP FS
0 dB gain, 2 VPP FS
3 dB gain, 1.4 VPP FS
TBD
66.1
TBD
0.39
87
RMS output noise
Inputs tied to common-mode
FIN = 10 MHz
FIN = 40 MHz
83
FIN = 70 MHz
TBD
TBD
TBD
82
FIN = 100 MHz
81
SFDR
Spurious free dynamic range
FIN = 150 MHz
80
0 dB gain, 2 VPP FS
74
FIN = 225 MHz
FIN = 300 MHz
3 dB gain, 1.4 VPP FS
0 dB gain, 2 VPP FS
3 dB gain, 1.4 VPP FS
TBD
70
TBD
69.8
69.2
69
FIN = 10 MHz
FIN = 40 MHz
FIN = 70 MHz
FIN = 100 MHz
FIN = 150 MHz
68.6
68
SINAD Signal to noise and distortion ratio
dBFS
0 dB gain, 2 VPP FS
3 dB gain, 1.4 VPP FS
0 dB gain, 2 VPP FS
3 dB gain, 1.4 VPP FS
66.1
TBD
65
FIN = 225 MHz
FIN = 300 MHz
TBD
92
FIN = 10 MHz
FIN = 40 MHz
FIN = 70 MHz
FIN = 100 MHz
FIN = 150 MHz
91
90
89
HD2
Second harmonic
87
dBc
0 dB gain, 2 VPP FS
3 dB gain, 1.4 VPP FS
0 dB gain, 2 VPP FS
3 dB gain, 1.4 VPP FS
76
FIN = 225 MHz
FIN = 300 MHz
TBD
73
TBD
(1) FS = Full scale range
5
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
ELECTRICAL CHARACTERISTICS (continued)
Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C,
AVDD = DRVDD = 3.3 V, sampling rate = 170 MSPS, sine wave input clock, 1.5 VPP differential clock amplitude, 50% clock
duty cycle, –1 dBFS differential analog input, internal reference mode, 0dB gain, DDR LVDS data output (unless otherwise
noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
87
MAX
UNIT
FIN = 10 MHz
FIN = 40 MHz
FIN = 70 MHz
FIN = 100 MHz
FIN = 150 MHz
83
TBD
82
81
HD3
Third harmonic
80
dBc
0 dB gain, 2 VPP FS
74
FIN = 225 MHz
FIN = 300 MHz
3 dB gain, 1.4 VPP FS
0 dB gain, 2 VPP FS
3 dB gain, 1.4 VPP FS
TBD
70
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
82
FIN = 10 MHz
FIN = 40 MHz
FIN = 70 MHz
FIN = 100 MHz
FIN = 150 MHz
FIN = 225 MHz
FIN = 300 MHz
FIN = 10 MHz
FIN = 40 MHz
FIN = 70 MHz
FIN = 100 MHz
FIN = 150 MHz
FIN = 225 MHz
FIN = 300 MHz
FIN = 10 MHz
Worst harmonic (other than HD2, HD3)
dBc
81
TBD
79
THD
Total harmonic distortion
78
dBc
77
73
68
ENOB
IMD
Effective number of bits
11.3
TBD
bits
dBFS
dBc
FIN1 = 50.09 MHz, FIN2 = 46.09 MHz, -7 dBFS
each tone
Two-tone intermodulation distortion
FIN1 = 135.08 MHz, FIN2 = 130.08 MHz, -7 dBFS
each tone
TBD
TBD
1
PSRR
AC power supply rejection ratio
Voltage overload recovery time
30 MHz, 200 mVPP signal on 3.3-V supply
Recovery to 1% (of final value) for 6-dB overload
with sine-wave input at Nyquist frequency
Clock
cycles
6
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
DIGITAL CHARACTERISTICS(1)
The DC specifications refer to the condition where the digital outputs are not switching, but are permanently at a valid logic
level 0 or 1 AVDD = DRVDD = 3.3 V, IO = 3.5 mA, RL = 100 Ω(2)
PARAMETER
DIGITAL INPUTS
TEST CONDITIONS
MIN
TYP
MAX UNIT
High-level input voltage
Low-level input voltage
High-level input current
Low-level input current
Input capacitance
2.4
V
0.8
V
33
–33
4
µA
µA
pF
DIGITAL OUTPUTS – CMOS MODE
High-level output voltage
Low-level output voltage
Output capacitance
3.3
0
V
V
Output capacitance inside the device, from each output to
ground
2
pF
DIGITAL OUTPUTS – LVDS MODE
High-level output voltage
1375
1025
350
mV
mV
mV
mV
Low-level output voltage
Output differential voltage, |VOD
|
225
VOS Output offset voltage, single-ended Common-mode voltage of OUTP and OUTM
1200
Output capacitance inside the device, from either output to
Output capacitance
ground
2
pF
(1) All LVDS and CMOS specifications are characterized, but not tested at production.
(2) IO refers to the LVDS buffer current setting, RL is the differential load resistance between the LVDS output pair.
TIMING CHARACTERISTICS – LVDS AND CMOS MODES(1)
Typical values are at 25°C, min and max values are across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD =
DRVDD = 3.3 V, sampling frequency = 170 MSPS, sine wave input clock, 1.5 VPP clock amplitude, CL = 5 pF(2), IO = 3.5 mA,
RL = 100 Ω(3), no internal termination, unless otherwise noted.
For timings at lower sampling frequencies, see the Output Timing section in the APPLICATION INFORMATION of this data
sheet.
PARAMETER
Aperture delay
TEST CONDITIONS
MIN
TYP
1.2
MAX UNIT
ns
ta
tj
Aperture jitter
150
fs rms
Time to valid data after coming out of
STANDBY mode
100
µs
Wake-up time
Time to valid data after stopping and
restarting the input clock
100
clock
cycles
Latency
14
(1) Timing parameters are specified by design and characterization and not tested in production.
(2) CL is the effective external single-ended load capacitance between each output pin and ground.
(3) IO refers to the LVDS buffer current setting; RL is the differential load resistance between the LVDS output pair.
7
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
TIMING CHARACTERISTICS – LVDS AND CMOS MODES (continued)
For timings at lower sampling frequencies, see the Output Timing section in the APPLICATION INFORMATION of this data
sheet.
PARAMETER
DDR LVDS MODE(4)
TEST CONDITIONS
MIN
TYP
MAX UNIT
tsu
Data setup time(5)
Data valid (6) to zero-cross of CLKOUTP
1.8
1.0
ns
ns
Zero-cross of CLKOUTP to data
becoming invalid(6)
th
Data hold time(5)
Input clock rising edge zero-cross to
output clock rising edge zero-cross
tPDI
Clock propagation delay
LVDS bit clock duty cycle
4.6
ns
Duty cycle of differential clock,
(CLKOUTP-CLKOUTM)
80 ≤ Fs ≤ 170 MSPS
50%
Rise time measured from –50 mV to 50
mV
tr ,
tf
Data rise time,
Data fall time
Fall time measured from 50 mV to –50
mV
50
50
100
100
200
ps
ps
1 ≤ Fs ≤ 170 MSPS
Rise time measured from –50 mV to 50
mV
Fall time measured from 50 mV to –50
mV
tCLKRISE
,
tCLKFALL
Output clock rise time,
Output clock fall time
200
1
1 ≤ Fs ≤ 170 MSPS
Output enable (OE) to valid data
delay
Time to valid data after OE becomes
active
tOE
µs
PARALLEL CMOS MODE
Data valid(7) to 50% of CLKOUT rising
edge
3.3
ns
(5)
tsu
th
Data setup time
50% of CLKOUT rising edge to data
becoming invalid(7)
(5)
Data hold time
1.2
2.7
ns
ns
Input clock rising edge zero-cross to
50% of CLKOUT rising edge
tPDI
Clock propagation delay
Output clock duty cycle
Duty cycle of output clock (CLKOUT)
80 ≤ Fs ≤ 170 MSPS
45%
Rise time measured from 20% to 80%
of DRVDD
Fall time measured from 80% to 20% of
DRVDD
tr ,
tf
Data rise time,
Data fall time
0.8
0.4
1.5
0.8
2
ns
1 ≤ Fs ≤ 170 MSPS
Rise time measured from 20% to 80%
of DRVDD
Fall time measured from 80% to 20% of
DRVDD
tCLKRISE
,
tCLKFALL
Output clock rise time,
Output clock fall time
1.2
50
ns
ns
1 ≤ Fs ≤ 170 MSPS
Output enable (OE) to valid data
delay
Time to valid data after OE becomes
active
tOE
(4) Measurements are done with a transmission line of 100 Ω characteristic impedance between the device and the load.
(5) Setup and hold time specifications take into account the effect of jitter on the output data and clock. These specifications also assume
that the data and clock paths are perfectly matched within the receiver. Any mismatch in these paths within the receiver would appear
as reduced timing margin.
(6) Data valid refers to logic high of +50 mV and logic low of –50 mV.
(7) Data valid refers to logic high of 2 V and logic low of 0.8 V
8
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
N+17
N+16
N+4
N+3
N+15
N+2
Sample
N
N+1
N+14
Input
Signal
ta
CLKP
Input
Clock
CLKM
CLKOUTM
CLKOUTP
tsu
th
tPDI
14 Clock Cycles
DDR
LVDS
Output Data
DXP, DXM
E
O
E
O
E
O
E
O
E
O
E
O
E
O
E
O
E
O
E
O
E – Even Bits D0,D2,D4,D6,D8,D10
O – Odd Bits D1,D3,D5,D7,D9,D11
N–14
N–13
N–12
N–11
N–10
N–1
N
N+1
N+2
tPDI
CLKOUT
tsu
Parallel
CMOS
14 Clock Cycles
th
Output Data
D0–D11
N–14
N–13
N–12
N–11
N–10
N–1
N
N+1
N+2
Figure 1. Latency
CLKM
Input
Clock
CLKP
tPDI
CLKOUTP
CLKOUTM
Output
Clock
th
tsu
tsu
th
Dn(1)
Dn+1(2)
Output
Data Pair
Dn_Dn+1_P,
Dn_Dn+1_M
(1)Dn – Bits D0, D2, D4, D6, D8, D10
(2)Dn+1 – Bits D1, D3, D5, D7, D9, D11
Figure 2. LVDS Mode Timing
9
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
CLKM
CLKP
Input
Clock
tPDI
Output
Clock
CLKOUT
th
tsu
Dn(1)
Output
Data
Dn
(1)Dn – Bits D0–D11
Figure 3. CMOS Mode Timing
10
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
DEVICE CONFIGURATION
ADS5525 offers flexibility with several programmable features that are easily configured.
The device can be configured independently using either a parallel interface control or a serial interface
programming.
In addition, the device supports a third configuration mode, where both the parallel interface and the serial
control registers are used. In this mode, the priority between the parallel and serial interfaces is determined by a
priority table (Table 2). If this additional level of flexibility is not required, the user can select either the serial
interface programming or the parallel interface control.
PARALLEL CONFIGURATION ONLY
To place the device in parallel configuration mode, keep RESET tied to high (DRVDD). Pins DFS, MODE, SEN,
and SDATA are used to directly control certain modes of the ADC. The device is configured by connecting the
parallel pins to the correct voltage levels (as described in Table 3 to Table 6). There is no need to apply reset.
In this mode, SEN and SDATA function as parallel interface control pins. Frequently used functions are
controlled in this mode—standby, selection between LVDS/CMOS output format, internal/external reference,
two's complement/straight binary output format, and position of the output clock edge.
Table 1 has a description of the modes controlled by the four parallel pins.
Table 1. Parallel Pin Definition
PIN
DFS
CONTROL MODES
DATA FORMAT and the LVDS/CMOS output interface
MODE
SEN
Internal or external reference
CLKOUT edge programmability
SDATA
STANDBY mode – Global (ADC, internal references and output buffers are powered down)
SERIAL INTERFACE CONFIGURATION ONLY
To exercise this mode, the serial registers must first be reset to their default values, and the RESET pin must be
kept low. In this mode, SEN, SDATA, and SCLK function as serial interface pins and are used to access the
internal registers of ADC. The registers are reset either by applying a pulse on the RESET pin, or by a high
setting on the <RST> bit (D1 in register 0x6C). The serial interface section describes the register programming
and register reset in more detail.
Since the parallel pins DFS and MODE are not used in this mode, they must be tied to ground.
CONFIGURATION USING BOTH THE SERIAL INTERFACE AND PARALLEL CONTROLS
For increased flexibility, an additional configuration mode is supported. A combination of serial interface registers
and parallel pin controls (DFS, MODE) are used to configure the device.
To exercise this mode, the serial registers must first be reset to their default values, and the RESET pin must be
kept low. In this mode, SEN, SDATA, and SCLK function as serial interface pins and are used to access the
internal registers of ADC. The registers are reset either by applying a pulse on RESET pin or by a high setting
on the <RST> bit (D1 in register 0x6C). The serial interface section describes the register programming and
register reset in more detail.
The parallel interface control pins DFS and MODE are used, and their function is determined by the appropriate
voltage levels as described in Table 5 and Table 6. The voltage levels are derived by using a resistor string as
illustrated in Figure 4. Since some functions are controlled using both the parallel pins and serial registers, the
priority between the two is determined by a priority table (Table 2).
11
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Table 2. Priority Between Parallel Pins and Serial Registers
PIN
FUNCTIONS SUPPORTED
PRIORITY
When using the serial interface, bit <REF> (register 0x6D, bit D4) controls this mode, ONLY
if the MODE pin is tied low.
MODE
Internal/External reference
When using the serial interface, bit <DF> (register 0x63, bit D3) controls this mode, ONLY if
the DFS pin is tied low.
DATA FORMAT
LVDS/CMOS
DFS
When using the serial interface, bit <ODI> (register 0x6C, bits D3-D4) controls LVDS/CMOS
selection independent of the state of DFS pin
AVDD
(2/3) AVDD
R
(2/3) AVDD
(1/3) AVDD
GND
AVDD
R
R
(1/3) AVDD
To Parallel Pin
Figure 4. Simple Scheme to Configure Parallel Pins
12
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
DESCRIPTION OF PARALLEL PINS
Table 3. SDATA Control Pin
SDATA (Pin 28)
DESCRIPTION
0
Normal operation (Default)
DRVDD
STANDBY. This is a global power down, where ADC, internal references and the output buffers are powered down.
Table 4. SEN Control Pin
SEN (Pin 27)
0
DESCRIPTION
CMOS mode: CLKOUT edge later by (3/12)Ts (1); LVDS mode: CLKOUT edge aligned with data transition
CMOS mode: CLKOUT edge later by (2/12)Ts (1); LVDS mode: CLKOUT edge aligned with data transition
CMOS mode: CLKOUT edge later by (1/12)Ts (1); LVDS mode: CLKOUT edge earlier by (1/12)Ts
(1/3)DRVDD
(2/3)DRVDD
DRVDD
(1)
Default CLKOUT position
(1) Ts = 1/Sampling Frequency
Table 5. DFS Control Pin
DFS (Pin 6)
DESCRIPTION
0
2's complement data and DDR LVDS output (Default)
2's complement data and parallel CMOS output
(1/3)DRVDD
(2/3)DRVDD
DRVDD
Offset binary data and parallel CMOS output
Offset binary data and DDR LVDS output
Table 6. MODE Control Pin
MODE (Pin 23)
0
DESCRIPTION
Internal reference
External reference
External reference
Internal reference
(1/3)AVDD
(2/3)AVDD
AVDD
SERIAL INTERFACE
The ADC has a set of internal registers, which can be accessed through the serial interface formed by pins SEN
(Serial interface Enable), SCLK (Serial Interface Clock), SDATA (Serial Interface Data) and RESET. After device
power-up, the internal registers must be reset to their default values by applying a high-going pulse on RESET
(of width greater than 10 ns).
Serial shift of bits into the device is enabled when SEN is low. Serial data SDATA is latched at every falling edge
of SCLK when SEN is active (low). The serial data is loaded into the register at every 16th SCLK falling edge
when SEN is low. If the word length exceeds a multiple of 16 bits, the excess bits are ignored. Data is loaded in
multiples of 16-bit words within a single active SEN pulse.
The first 8 bits form the register address and the remaining 8 bits form the register data.
REGISTER INITIALIZATION
After power-up, the internal registers must be reset to their default values. This is done in one of two ways:
1. Either through hardware reset by applying a high-going pulse on RESET pin (of width greater than 10 ns) as
shown in Figure 5.
OR
2. By applying software reset. Using the serial interface, set the <RST> bit (D1 in register 0x6C) to high. This
initializes the internal registers to their default values and then self-resets the <RST> bit to low. In this case
the RESET pin is kept low.
13
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Register Address
Register Data
SDATA
A7
A6
A5
A4
A3
A2
A1
A0
D7
D6
D5
D4
D3
D2
t(DH)
D1
D0
t(SCLK)
t(DSU)
SCLK
t(SLOADH)
t(SLOADS)
SEN
RESET
T0109-01
Figure 5. Serial Interface Timing Diagram
SERIAL INTERFACE TIMING CHARACTERISTICS
Typical values at 25°C, min and max values across the full temperature range TMIN = –40°C to TMAX = 85°C,
AVDD = DRVDD = 3.3 V (unless otherwise noted)
MIN
TYP
MAX
UNIT
tSCLK
SCLK period
50
ns
SCLK duty cycle
50%
25
tSLOADS
tSLOADH
tDSU
SEN to SCLK setup time
SCLK to SEN hold time
SDATA setup time
SDATA hold time
ns
ns
ns
ns
25
25
tDH
25
RESET TIMING
Typical values at 25°C, min and max values across the full temperature range TMIN = –40°C to TMAX = 85°C,
AVDD = DRVDD = 3.3 V (unless otherwise noted)
PARAMETER
Power-on delay
Reset pulse width
Register write delay
Power-up time
TEST CONDITIONS
MIN
5
TYP
MAX
UNIT
ms
ns
t1
Delay from power-up of AVDD and DRVDD to RESET pulse active
Pulse width of active RESET signal
t2
10
25
t3
Delay from RESET disable to SEN active
ns
tPO
Delay from power-up of AVDD and DRVDD to output stable
6.5
ms
14
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Power Supply
AVDD, DRVDD
t1
RESET
t2
t3
SEN
T0108-01
NOTE: A high-going pulse on RESET pin is required in serial interface mode in case of initialization through hardware reset.
For parallel interface operation, RESET has to be tied permanently HIGH.
Figure 6. Reset Timing Diagram
15
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
DESCRIPTION OF SERIAL REGISTERS
Table 7 gives a summary of all the modes that can be programmed through the serial interface.
Table 7. Serial Interface Register Map
REGISTER ADDRESS
REGISTER DATA
D4 D3 D2 D1 D0
DESCRIPTION
A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5
<STBY> – Global Power Down
NORMAL converter operation (Default after
reset)
0
0
1
1
1
1
0
0
0
0
0
0
1
1
1
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
STANDBY
<RST> – Software Reset
0
1
1
0
1
1
0
0
0
0
0
0
0
0
1
0
Resets all registers to default values
<DF> – Output Data Format
2's complement output format (Default after
reset)
0
0
1
1
1
1
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
Straight binary output format
<ODI> – Output Data Interface
DDR LVDS outputs (D4:D3 defaults to 00
after reset)
0
0
1
1
1
1
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
0
0
Parallel CMOS outputs
<REF> –Internal/External reference mode
0
0
1
1
1
1
0
0
1
1
1
1
0
0
1
1
0
0
0
0
0
0
0
0
Internal reference (Default after reset)
External reference – Force voltage on VCM
pin
0
0
0
1
0
0
0
0
<TEST PATTERN> – Output test pattern on data outputs
0
0
0
1
1
1
1
1
1
0
0
0
0
0
0
1
1
1
0
0
0
1
1
1
0
0
0
0
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Normal operation (Default after reset)
All zeros
All ones
Toggle pattern Alternate 1s and 0s on each
data output and across the data outputs.
0
0
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
1
1
0
1
0
0
0
0
0
0
0
0
0
0
0
Ramp pattern – Output data ramps from
0x000 to 0xFFF every clock cycle
Custom pattern. Write the custom pattern in
CUSTOM PATTERN registers A and B.
0
0
1
1
1
1
0
0
0
0
1
1
0
0
1
1
1
0
1
0
0
0
0
0
0
0
0
0
0
X
X
X
NOT USED
<CUSTOM PATTERN> – Output custom pattern on data outputs
0
0
1
1
1
1
0
0
1
1
0
0
0
1
1
0
D5 D4 D3
D2
D1
D0
0
0
CUSTOM PATTERN D5-D0
0
0
D11 D10 D9
D8 D7 D6 CUSTOM PATTERN D11-D6
<CLK GAIN> – Clock Buffer gain programmability, Gain decreases monotonically from Gain 4 to Gain 0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
1
1
1
1
1
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
0
0
0
0
0
1
0
0
0
0
0
1
0
0
1
1
1
0
1
0
0
0
0
1
Gain 4
Gain 3
Gain 2
Gain 1 (Default after reset)
Gain 0 Minimum gain
<POWER SCALING> Power scaling vs sampling frequency. The ADC can be operated at reduced power at lower sampling rates
with no loss in performance.
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
1
0
1
0
0
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Default Fs > 150 MSPS (Default after reset)
Power Mode 1 – 105 < Fs ≤ 150 MSPS
Power Mode 2 – 50 < Fs ≤ 105 MSPS
Power Mode 3 – Fs ≤ 50 MSPS
16
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Table 7. Serial Interface Register Map (continued)
REGISTER ADDRESS
REGISTER DATA
DESCRIPTION
A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5
D4
D3
D2 D1 D0
<GAIN> Gain programming - Channel gain can be programmed from 0 to 6 dB for SFDR/SNR trade-off. For each gain setting, the
input full-scale range has to be proportionally scaled. For 6 dB gain, the full-scale range will be 1 VPP compared to 2 VPP at 0 dB
gain.
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
0
1
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
0 dB (Default after reset)
1 dB
2 dB
3 dB
4 dB
5 dB
6 dB
<LVDS CURRENT> – LVDS Output data and clock buffers nominal current programmability
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
3.5 mA (Default after reset)
2.5 mA
4.5 mA
1.75 mA
<CURRENT DOUBLE> – The output data and clock buffer currents are doubled from the value selected by the <LVDS CURRENT>
register.
value specified by <LVDS CURRENT>
(Default after reset)
0
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
1
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2x data, 2x clock currents
1x data, 2x clock currents
2x data, 4x clock currents
<DATA TERM> Internal termination - Option to terminate the LVDS DATA buffers inside the ADC to improve signal integrity. By
default, internal termination is disabled.
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
No termination (Default after reset)
325 Ω
200 Ω
125 Ω
170 Ω
120 Ω
100 Ω
75 Ω
<CLK TERM> Internal termination - Option to terminate the LVDS CLK buffers inside the ADC to improve signal integrity. By
default, internal termination is disabled.
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
No termination (Default after reset)
325 Ω
200 Ω
125 Ω
170 Ω
120 Ω
100 Ω
75 Ω
(1)
<CLKOUT POSN CMOS> – Output clock rising edge programmability in CMOS mode
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
1
1
1
1
Default position
CLKOUT rising edge later by (1/12)Ts
CLKOUT rising edge later by (3/12)Ts
CLKOUT rising edge later by (2/12)Ts
(1) Ts = 1/Sampling Frequency
17
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Table 7. Serial Interface Register Map (continued)
REGISTER ADDRESS
REGISTER DATA
DESCRIPTION
A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5
D4
D3
D2 D1 D0
(2)
<CLKOUT POSN CMOS> – Output clock falling edge programmability in CMOS mode
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
0
0
0
0
0
0
0
0
1
1
1
1
Default position
CLKOUT falling edge later by (1/12)Ts
CLKOUT falling edge later by (3/12)Ts
CLKOUT falling edge later by (2/12)Ts
(2)
<CLKOUT POSN LVDS> – Output clock rising edge programmability in LVDS mode
0
0
1
1
1
1
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
Default position
CLKOUT rising edge earlier by (1/12)Ts
CLKOUT rising edge aligned with data
transition
0
0
1
1
1
1
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
1
1
CLKOUT rising edge aligned with data
transition
(2)
<CLKOUT POSN LVDS> – Output clock falling edge programmability in LVDS mode
0
0
1
1
1
1
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
1
1
Default position
CLKOUT falling edge earlier by (1/12)Ts
CLKOUT falling edge aligned with data
transition
0
0
1
1
1
1
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
1
1
0
1
0
0
0
0
1
1
CLKOUT falling edge aligned with data
transition
(2) Ts = 1/Sampling Frequency
18
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
PIN CONFIGURATION (LVDS MODE)
RGZ PACKAGE
(TOP VIEW)
1
36
35
34
33
32
31
30
29
28
27
26
25
DRGND
DRVDD
OVR
DRGND
DRVDD
NC
2
3
4
CLKOUTM
CLKOUTP
DFS
NC
5
NC
6
NC
7
OE
RESET
SCLK
SDATA
SEN
8
AVDD
9
AGND
CLKP
10
11
12
CLKM
AVDD
AGND
AGND
Figure 7. LVDS Mode Pinout
PIN ASSIGNMENTS – LVDS Mode
PIN
TYPE
PIN
NUMBER
NUMBER
OF PINS
PIN NAME
DESCRIPTION
8, 18, 20,
22, 24, 26
AVDD
Analog power supply
I
6
9, 12, 14,
17, 19, 25
AGND
Analog ground
I
6
CLKP, CLKM
INP, INM
Differential clock input
I
I
10, 11
15, 16
2
2
Differential analog input
Internal reference mode – Common-mode voltage output.
External reference mode – Reference input. The voltage forced on this pin sets
the internal references.
VCM
IREF
I/O
I
13
21
1
1
Current-set resistor, 56.2-kΩ resistor to ground.
Serial interface RESET input.
When using the serial interface mode, the user MUST initialize internal registers
through hardware RESET by applying a high-going pulse on this pin, or by using
the software reset option. See the SERIAL INTERFACE section.
In parallel interface mode, the user has to tie the RESET pin permanently HIGH.
(SDATA and SEN are used as parallel pin controls in this mode)
The pin has an internal 100-kΩ pull-down resistor.
RESET
SCLK
I
I
30
29
1
1
Serial interface clock input. The pin has an internal 100-kΩ pull-down resistor.
19
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
PIN CONFIGURATION (LVDS MODE) (continued)
PIN ASSIGNMENTS – LVDS Mode (continued)
PIN
TYPE
PIN
NUMBER
NUMBER
OF PINS
PIN NAME
DESCRIPTION
This pin functions as serial interface data input when RESET is low. It functions
as STANDBY control pin when RESET is tied high.
SDATA
SEN
I
28
27
1
1
See Table 3 for detailed information.
The pin has an internal 100 kΩ pull-down resistor.
This pin functions as serial interface enable input when RESET is low. It functions
as CLKOUT edge programmability when RESET is tied high. See Table 4 for
detailed information.
I
The pin has an internal 100-kΩ pull-up resistor to DRVDD.
Output buffer enable input, active high. The pin has an internal 100-kΩ pull-up
resistor to DRVDD.
OE
I
I
I
7
6
1
1
1
Data Format Select input. This pin sets the DATA FORMAT (Twos complement or
Offset binary) and the LVDS/CMOS output mode type. See Table 5 for detailed
information.
DFS
MODE
Mode select input. This pin selects the Internal or External reference mode. See
Table 6 for detailed information.
23
CLKOUTP
CLKOUTM
D0_D1_P
D0_D1_M
D2_D3_P
D2_D3_M
D4_D5_P
D4_D5_M
D6_D7_P
D6_D7_M
D8_D9_P
D8_D9_M
D10_D11_P
D10_D11_M
OVR
Differential output clock, true
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
I
5
4
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
4
Differential output clock, complement
Differential output data D0 and D1 multiplexed, true
Differential output data D0 and D1 multiplexed, complement.
Differential output data D2 and D3 multiplexed, true
Differential output data D2 and D3 multiplexed, complement
Differential output data D4 and D5 multiplexed, true
Differential output data D4 and D5 multiplexed, complement
Differential output data D6 and D7 multiplexed, true
Differential output data D6 and D7 multiplexed, complement
Differential output data D8 and D9 multiplexed, true
Differential output data D8 and D9 multiplexed, complement
Differential output data D10 and D11 multiplexed, true
Differential output data D10 and D11 multiplexed, complement
Out-of-range indicator, CMOS level signal
38
37
40
39
42
41
44
43
46
45
48
47
3
DRVDD
Digital and output buffer supply
2, 35
1, 36
DRGND
Digital and output buffer ground
I
NC
Do not connect
31, 32, 33,
34
20
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
PIN CONFIGURATION (CMOS MODE)
RGZ PACKAGE
(TOP VIEW)
1
36
35
34
33
32
31
30
29
28
27
26
25
DRGND
DRVDD
OVR
DRGND
DRVDD
NC
2
3
4
UNUSED
CLKOUT
DFS
NC
5
NC
6
NC
7
OE
RESET
SCLK
SDATA
SEN
8
AVDD
AGND
CLKP
9
10
11
12
CLKM
AGND
AVDD
AGND
Figure 8. CMOS Mode Pinout
PIN ASSIGNMENTS – CMOS Mode
PIN
TYPE
PIN
NUMBER
NUMBER
OF PINS
PIN NAME
AVDD
DESCRIPTION
8, 18, 20,
22, 24, 26
Analog power supply
Analog ground
I
6
9, 12, 14, 17,
19, 25
AGND
I
6
CLKP, CLKM Differential clock input
I
I
10, 11
15, 16
2
2
INP, INM
Differential analog input
Internal reference mode – Common-mode voltage output.
External reference mode – Reference input. The voltage forced on this pin sets
the internal references.
VCM
I/O
I
13
21
1
1
IREF
Current-set resistor, 56.2-kΩ resistor to ground.
Serial interface RESET input.
When using the serial interface mode, the user MUST initialize internal registers
through hardware RESET by applying a high-going pulse on this pin, or by using
the software reset option. See the SERIAL INTERFACE section.
RESET
SCLK
I
I
30
29
1
1
In parallel interface mode, the user has to tie RESET pin permanently HIGH.
(SDATA and SEN are used as parallel pin controls in this mode).
The pin has an internal 100-kΩ pull-down resistor.
Serial interface clock input. The pin has an internal 100-kΩ pull-down resistor.
21
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
PIN CONFIGURATION (CMOS MODE) (continued)
PIN ASSIGNMENTS – CMOS Mode (continued)
PIN
PIN
NUMBER
NUMBER
OF PINS
PIN NAME
DESCRIPTION
TYPE
This pin functions as serial interface data input when RESET is low. It functions as
STANDBY control pin when RESET is tied high.
SDATA
SEN
I
I
28
27
1
1
See Table 3 for detailed information.
The pin has an internal 100 kΩ pull-down resistor.
This pin functions as serial interface enable input when RESET is low. It functions
as CLKOUT edge programmability when RESET is tied high. See Table 4 for
detailed information.
The pin has an internal 100-kΩ pull-up resistor to DRVDD.
Output buffer enable input, active high. The pin has an internal 100-kΩ pull-up
resistor to DRVDD.
OE
I
I
I
7
6
1
1
1
Data Format Select input. This pin sets the DATA FORMAT (Twos complement or
Offset binary) and the LVDS/CMOS output mode type. See Table 5 for detailed
information.
DFS
MODE
Mode select input. This pin selects the internal or external reference mode. See
Table 6 for detailed information.
23
CLKOUT
D0
CMOS output clock
O
O
O
O
O
O
O
O
O
O
O
O
O
O
I
5
37
38
39
40
41
42
43
44
45
46
47
48
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
1
4
CMOS output data D0
CMOS output data D1
CMOS output data D2
CMOS output data D3
CMOS output data D4
CMOS output data D5
CMOS output data D6
CMOS output data D7
CMOS output data D8
CMOS output data D9
CMOS output data D10
CMOS output data D11
Out-of-range indicator, CMOS level signal
Digital and output buffer supply
Digital and output buffer ground
Unused pin in CMOS mode
Do not connect
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
OVR
DRVDD
DRGND
UNUSED
NC
2, 35
1, 36
4
I
31, 32, 33,
34
22
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
TYPICAL CHARACTERISTICS
All plots are at 25°C, AVDD = DRVDD = 3.3 V, sampling frequency = 170 MSPS, sine wave input clock, 1.5 VPP differential
clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain, DDR LVDS
data output (unless otherwise noted)
FFT for 10 MHz INPUT SIGNAL
FFT for 40 MHz INPUT SIGNAL
Figure 9.
Figure 10.
FFT for 70 MHz INPUT SIGNAL
FFT for 100 MHz INPUT SIGNAL
Figure 11.
Figure 12.
FFT for 130 MHz INPUT SIGNAL
FFT for 150 MHz INPUT SIGNAL
Figure 13.
Figure 14.
23
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
TYPICAL CHARACTERISTICS (continued)
All plots are at 25°C, AVDD = DRVDD = 3.3 V, sampling frequency = 170 MSPS, sine wave input clock, 1.5 VPP differential
clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain, DDR LVDS
data output (unless otherwise noted)
FFT for 200 MHz INPUT SIGNAL
FFT for 225 MHz INPUT SIGNAL
Figure 15.
Figure 16.
FFT for 300 MHz INPUT SIGNAL
FFT for 375 MHz INPUT SIGNAL
Figure 17.
Figure 18.
FFT for 500 MHz INPUT SIGNAL
INTERMODULATION DISTORTION (IMD) vs FREQUENCY
Figure 19.
Figure 20.
24
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
TYPICAL CHARACTERISTICS (continued)
All plots are at 25°C, AVDD = DRVDD = 3.3 V, sampling frequency = 170 MSPS, sine wave input clock, 1.5 VPP differential
clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain, DDR LVDS
data output (unless otherwise noted)
INTERMODULATION DISTORTION (IMD) vs FREQUENCY
SFDR vs INPUT FREQUENCY
Figure 21.
Figure 22.
SNR vs INPUT FREQUENCY
SNR vs INPUT FREQUENCY
Figure 23.
Figure 24.
SFDR vs GAIN
SNR vs GAIN
Figure 25.
Figure 26.
25
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
TYPICAL CHARACTERISTICS (continued)
All plots are at 25°C, AVDD = DRVDD = 3.3 V, sampling frequency = 170 MSPS, sine wave input clock, 1.5 VPP differential
clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain, DDR LVDS
data output (unless otherwise noted)
PERFORMANCE vs AVDD
PERFORMANCE vs DRVDD
Figure 27.
Figure 28.
SNR vs SAMPLING FREQUENCY
ACROSS POWER SCALING MODES
PERFORMANCE vs TEMPERATURE
Figure 29.
Figure 30.
POWER DISSIPATION vs
SAMPLING FREQUENCY
PERFORMANCE vs
INPUT AMPLITUDE
Figure 31.
Figure 32.
26
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
TYPICAL CHARACTERISTICS (continued)
All plots are at 25°C, AVDD = DRVDD = 3.3 V, sampling frequency = 170 MSPS, sine wave input clock, 1.5 VPP differential
clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain, DDR LVDS
data output (unless otherwise noted)
PERFORMANCE vs CLOCK AMPLITUDE
PERFORMANCE vs INPUT CLOCK DUTY CYCLE
Figure 33.
Figure 34.
OUTPUT NOISE HISTOGRAM WITH
INPUTS SHORTED TO COMMON-MODE
PERFORMANCE IN EXTERNAL REFERENCE MODE
Figure 35.
Figure 36.
COMMON-MODE REJECTION RATIO vs FREQUENCY
Figure 37.
27
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
TYPICAL CHARACTERISTICS (continued)
All plots are at 25°C, AVDD = DRVDD = 3.3 V, sampling frequency = 170 MSPS, sine wave input clock, 1.5 VPP differential
clock amplitude, 50% clock duty cycle, –1 dBFS differential analog input, internal reference mode, 0 dB gain, DDR LVDS
data output (unless otherwise noted)
70
66
68
TBD
64
70
66
f
- Input Frequency - MHz
IN
SNR - dBFS
Figure 38. SNR Contour in dBFS
85
65
55
75
60
75
80
70
85
75
65
TBD
60
55
70
80
85
f
- Input Frequency - MHz
IN
SFDR - dBc
Figure 39. SFDR Contour in dBc
28
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
APPLICATION INFORMATION
THEORY OF OPERATION
ADS5525 is a low power 12-bit 170 MSPS pipeline ADC in a CMOS process. ADS5525 is based on switched
capacitor technology and runs off a single 3.3-V supply. The conversion process is initiated by a rising edge of
the external input clock. Once the signal is captured by the input sample and hold, the input sample is
sequentially converted by a series of lower resolution stages, with the outputs combined in a digital correction
logic block. At every clock edge, the sample propagates through the pipeline resulting in a data latency of 14
clock cycles. The output is available as 12-bit data, in DDR LVDS or CMOS and coded in either straight offset
binary or binary 2’s complement format.
ANALOG INPUT
The analog input consists of a switched-capacitor based differential sample and hold architecture, shown in
Figure 40.
This differential topology results in good ac-performance even for high input frequencies at high sampling rates.
The INP and INM pins have to be externally biased around a common-mode voltage of 1.5 V available on VCM
pin 13. For a full-scale differential input, each input pin INP, INM has to swing symmetrically between VCM +
0.5 V and VCM – 0.5 V, resulting in a 2-VPP differential input swing. The maximum swing is determined by the
internal reference voltages REFP (2.5 V nominal) and REFM (0.5 V, nominal).
CS = 3.2 pF
RS = 25 W
INP
CP
CS = 3.2 pF
RS = 25 W
INM
CP
S0162-01
Figure 40. Input Stage
Driving Circuit
For optimum performance, the analog inputs have to be driven differentially. This improves the common-mode
noise immunity and even order harmonic rejection. Input configurations using RF transformers suitable for low
and high input frequencies are shown in Figure 41 and Figure 42. The single-ended signal is fed to the primary
winding of the RF transformer. The transformer is terminated by 50-Ω on the secondary side. Putting the
termination on the secondary side helps to shield the kickbacks caused by the input sampling capacitors from
the RF transformer’s leakage inductances. The termination is accomplished by two 25 Ω connected in series,
with the center point connected to the 1.5-V common-mode (VCM pin 13). The 4.7-Ω resistor in series with each
input pin is required to dampen the ringing caused by the device package parasitics (shown in Figure 40).
29
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
APPLICATION INFORMATION (continued)
ADS5525
ADT1-1T
0.1 mF
4.7 W
INP
25 W
25 W
0.1 mF
INM
4.7 W
1:1
VCM
A. Components shown inside the shaded box are NOT required for the ADS5525. It is ONLY a provision that
allows seamless transition to potential derivatives of the ADS5525.
Figure 41. Drive Circuit at Low Input Frequencies
At high input frequencies, the mismatch in the transformer parasitic capacitance (between the windings) results
in degraded even-order harmonic performance. Connecting two identical RF transformers back to back helps
minimize this mismatch and good performance is obtained for high frequency input signals. An additional
termination resistor pair is required between the two transformers as shown in the Figure 42. The center point of
this termination is connected to ground to improve the balance between the P and M sides. The values of the
terminations between the transformers and on the secondary side have to be chosen to get an overall 50 Ω (in
the case of 50-Ω source impedance).
ADS5525
TC4-1W
TC4-1W
0.1 mF
4.7 W
INP
200 W
50 W
50 W
0.1 mF
200 W
INM
4.7 W
1:2
2:1
VCM
A. Components shown inside the shaded box are NOT required for the ADS5525. It is ONLY a provision that
allows seamless transition to potential derivatives of the ADS5525.
Figure 42. Drive Circuit at High Input Frequencies
30
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
APPLICATION INFORMATION (continued)
Input Common-Mode
To ensure a low-noise common-mode reference, the VCM pin is filtered with a 0.1-µF low-inductance capacitor
connected to ground. The VCM pin is designed to directly drive the ADC inputs. The input stage of the ADC
sinks a common-mode current in the order of 280 µA (at 170 MSPS). Equation 1 describes the dependency of
the common-mode current and the sampling frequency.
(280 mA) x Fs
170 MSPS
(1)
This equation helps to design the output capability and impedance of the CM driving circuit accordingly.
Reference
ADS5525 has built-in internal references REFP and REFM, requiring no external components. Design schemes
are used to linearize the converter load seen by the references; this and the integration of the requisite
reference capacitors on-chip eliminates the need for external decoupling. The full-scale input range of the
converter can be controlled in the external reference mode as explained below. The internal or external
reference modes can be selected by controlling the MODE pin 23 (see Table 6 for details) or by programming
the serial interface register bit <REF>.
INTREF
Internal
Reference
VCM
INTREF
EXTREF
REFM
REFP
ADS5525
Figure 43. Reference Section
Internal Reference
When the device is in internal reference mode, the REFP and REFM voltages are generated internally.
Common-mode voltage (1.5 V nominal) is output on VCM pin, which can be used to externally bias the analog
input pins.
External Reference
When the device is in external reference mode, the VCM acts as a reference input pin. The voltage forced on
the VCM pin is buffered and gained by 1.33 internally, generating the REFP and REFM voltages. The differential
input voltage corresponding to full-scale is given by Equation 2.
31
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
APPLICATION INFORMATION (continued)
Full−scale differential input pp + (Voltage forced on VCM) 1.33
(2)
In this mode, the 1.5 V common-mode voltage to bias the input pins has to be generated externally. There is no
change in performance compared to internal reference mode.
Clock Input
ADS5525 clock inputs can be driven differentially (SINE, LVPECL or LVDS) or single-ended (LVCMOS), with
little or no difference in performance between configurations. The common-mode voltage of the clock inputs is
set to VCM using internal 5-kΩ resistors as shown in Figure 44. This allows the use of transformer-coupled drive
circuits for sine wave clock, or ac-coupling for LVPECL, LVDS clock sources (Figure 45 and Figure 46)
VCM
VCM
5 kW
5 kW
CLKP
CLKM
Figure 44. Internal Clock Buffer
For best performance, it is recommended to drive the clock inputs differentially, reducing susceptibility to
common-mode noise. In this case, it is best to connect both clock inputs to the differential input clock signal with
0.1-µF capacitors, as shown in Figure 45.
0.1 mF
CLKP
Differential Sine-Wave
or PECL or LVDS
Clock Input
0.1 mF
CLKM
ADS5525
Figure 45. Differential Clock Driving Circuit
32
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
APPLICATION INFORMATION (continued)
A single-ended CMOS clock can be ac-coupled to the CLKP input, with CLKM (pin 11) connected to ground with
a 0.1-µF capacitor, as shown in Figure 46.
0.1 mF
CMOS Clock Input
CLKP
0.1 mF
CLKM
ADS5525
Figure 46. Single-Ended Clock Driving Circuit
For best performance, the clock inputs have to be driven differentially, reducing susceptibility to common-mode
noise. For high input frequency sampling, it is recommended to use a clock source with very low jitter. Bandpass
filtering of the clock source can help reduce the effect of jitter. There is no change in performance with a
non-50% duty cycle clock input. Figure 34 shows the performance variation of the ADC versus clock duty cycle
Clock Buffer Gain
When using a sinusoidal clock input, the noise contributed by clock jitter improves as the clock amplitude is
increased. Therefore, using a large amplitude clock is recommended. In addition, the clock buffer has a
programmable gain option to amplify the input clock. The clock buffer gain can be set by programming the
register bits <CLK GAIN>. The clock buffer gain decreases monotonically from Gain 4 to Gain 0 settings.
33
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
APPLICATION INFORMATION (continued)
Table 8. Clock Buffer Gain Programming
REGISTER DATA
REGISTER ADDRESS
A5 A4 A3 A2
<CLK GAIN> – Clock buffer gain programmability, Gain decreases monotonically from Gain 4 to Gain 0
DESCRIPTION
A7
A6
A1
A0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
1
1
1
1
1
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
0
0
0
0
0
1
0
0
0
0
0
1
0
0
1
1
1
0
1
0
0
0
0
1
Gain 4
Gain 3
Gain 2
Gain 1 Default gain
Gain 0 Minimum gain
Programmable Gain
ADS5525 has programmable gain from 0 dB to 6 dB in steps of 1 dB. The corresponding full-scale input range
varies from 2 VPP down to 1 VPP, with 0 dB being the default gain. At high IF, this is especially useful as the
SFDR improvement is significant with marginal degradation in SNR.
The gain can be programmed using the serial interface (bits D3-D0 in register 0x68).
Table 9. Programmable Gain
REGISTER ADDRESS
A5 A4 A3 A2
REGISTER DATA
D5 D4 D3 D2
DESCRIPTION
A7
A6
A1
A0
D7
D6
D1
D0
<GAIN> Gain programming - Channel gain can be programmed from 0 to 6 dB for SFDR/SNR trade-off. For each gain setting, the
input full-scale range has to be proportionally scaled. For 6 dB gain, the full-scale range will be 1 VPP compared to 2 VPP at 0 dB
gain.
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
0
0
0
0
1
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
0 dB Default after reset
1 dB
2 dB
3 dB
4 dB
5 dB
6 dB
Power Down
ADS5525 has three power-down modes – global STANDBY, output buffer disabled, and input clock stopped.
Global STANDBY
This mode can be initiated by controlling SDATA (pin 28) or by setting the register bit <STBY> through the serial
interface. In this mode, the A/D converter, reference block and the output buffers are powered down and the
total power dissipation reduces to about 100 mW. The output buffers are in high impedance state. The wake-up
time from the global power down to data becoming valid normal mode is maximum 100 µs.
Output Buffer Disable
The output buffers can be disabled using OE pin 7 in both the LVDS and CMOS modes, reducing the total
power by about 100 mW. With the buffers disabled, the outputs are in high impedance state. The wake-up time
from this mode to data becoming valid in normal mode is maximum 1 µs in LVDS mode and 50 ns in CMOS
mode.
Input Clock Stop
The converter enters this mode when the input clock frequency falls below 1 MSPS. The power dissipation is
about 100 mW and the wake-up time from this mode to data becoming valid in normal mode is maximum
100 µs.
34
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Power Scaling Modes
ADS5525 has a power scaling mode in which the device can be operated at reduced power levels at lower
sampling frequencies with no difference in performance. (See Figure 30)(1) There are four power scaling modes
for different sampling clock frequency ranges, using the serial interface register bits <POWER SCALING>. Only
the AVDD power is scaled, leaving the DRVDD power unchanged.
Table 10. Power Scaling vs Sampling Speed
Sampling Frequency
MSPS
Analog Power
(Typical)
Power Scaling Mode
Analog Power in Default Mode
> 150
105 to 150
50 to 105
< 50
Default
960 mW at 170 MSPS
841 mW at 150 MSPS
670 mW at 105 MSPS
525 mW at 50 MSPS
960 mW at 170 MSPS
917 mW at 150 MSPS
830 mW at 105 MSPS
760 mW at 50 MSPS
Power Mode 1
Power Mode 2
Power Mode 3
(1) The performance in the power scaling modes is from characterization and not tested in production.
REGISTER ADDRESS REGISTER DATA
A5 A4 A3 A2 D5 D4 D3 D2
DESCRIPTION
A7
A6
A1
A0
D7
D6
D1
D0
<POWER SCALING> Power scaling vs sampling frequency. The ADC can be operated at reduced power at lower sampling rates
with no loss in performance.
0
1
1
0
1
1
0
1
0
0
1
0
0
0
0
0
Default Fs > 150 MSPS Default after
reset
Power Mode1 105 < Fs ≤ 150
MSPS
0
1
1
0
1
1
0
1
1
0
1
0
0
0
0
0
Power Mode2 50 < Fs ≤ 105
MSPS
0
0
1
1
1
1
0
0
1
1
1
1
0
0
1
1
0
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
Power Mode3 Fs ≤ 50 MSPS
Power Supply Sequence
During power-up, the AVDD and DRVDD supplies can come up in any sequence. The two supplies are
separated inside the device. Externally, they can be driven from separate supplies or from a single supply.
35
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Digital Output Information
ADS5525 provides 12-bit data, an output clock synchronized with the data and an out-of-range indicator that
goes high when the output reaches the full-scale limits. In addition, output enable control (OE pin 7) is provided
to power down the output buffers and put the outputs in high-impedance state.
Output Interface
Two output interface options are available – Double Data Rate (DDR) LVDS and parallel CMOS. They can be
selected using the DFS (see Table 5) or the serial interface register bit <ODI>.
DDR LVDS Outputs
In this mode, the 12 data bits and the output clock are available as LVDS (Low Voltage Differential Signal)
levels. Two successive data bits are multiplexed and output on each LVDS differential pair as shown in
Figure 47. So, there are 6LVDS output pairs for the 12 data bits and 1 LVDS output pair for the output clock.
Pins
CLKOUTP
Output Clock
CLKOUTM
D0_D1_P
Data Bits D0. D1
D0_D1_M
D2_D3_P
Data Bits D2, D3
D2_D3_M
D4_D5_P
Data Bits D4, D5
D4_D5_M
D6_D7_P
Data Bits D6, D7
D6_D7_M
D8_D9_P
Data Bits D8, D9
D8_D9_M
D10_D11_P
Data Bits D10, D11
D10_D11_M
OVR
Out-of-Range Indicator
ADS5525
Figure 47. DDR LVDS Outputs
Even data bits D0, D2, D4, D6, D8 and D10 are output at the falling edge of CLKOUTP and the odd data bits
D1, D3, D5, D7, D9 and D11 are output at the rising edge of CLKOUTP. Both the rising and falling edges of
CLKOUTP have to be used to capture all the 12 data bits (see Figure 48).
36
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
CLKOUTP
CLKOUTM
D0_D1_P,
D0_D1_M
D0
D2
D1
D3
D5
D7
D9
D11
D0
D2
D1
D3
D5
D7
D9
D11
D2_D3_P,
D2_D3_M
D4_D5_P,
D4_D5_M
D4
D4
D6_D7_P,
D6_D7_M
D6
D6
D8_D9_P,
D8_D9_M
D8
D8
D10_D11_P,
D10_D11_M
D10
D10
Sample N
Sample N+1
Figure 48. DDR LVDS Interface
LVDS Buffer Current Programmability
The default LVDS buffer output current is 3.5 mA. When terminated by 100 Ω, this results in a 350-mV
single-ended voltage swing (700-mVPP differential swing). The LVDS buffer currents can also be programmed to
2.5 mA, 4.5 mA, and 1.75 mA using the serial interface. In addition, there exists a current double mode, where
this current is doubled for the data and output clock buffers.
37
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Table 11. LVDS Buffer Currents Programming
REGISTER ADDRESS
REGISTER DATA
DESCRIPTION
A7
A6
A5
A4
A3
A2
A1
A0
D7
D6
D5
D4
D3
D2
D1
D0
<LVDS CURRENT> – Output data and clock buffers current programmability
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
3.5 mA Default after reset
2.5 mA
4.5 mA
1.75 mA
<CURRENT DOUBLE> – The output data and clock buffer currents are doubled from the value selected by the <LVDS CURRENT>
register.
Value specified by <LVDS
0
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
CURRENT>Default after reset
2x data, 2x clock currents
1x data, 2x clock currents
2x data, 4x clock currents
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
1
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
LVDS Buffer Internal Termination
An internal termination option is available (using the serial interface), by which the LVDS buffers are differentially
terminated inside the device. The termination resistances available are – 325, 200, and 170 Ω (nominal with
±20% variation). Any combination of these three terminations can be programmed; the effective termination is
the parallel combination of the selected resistances. This results in eight effective terminations from open (no
termination) to 75 Ω.
The internal termination helps to absorb any reflections coming from the receiver end, improving the signal
integrity. With 100-Ω internal and 100-Ω external termination, the voltage swing at the receiver end is halved
(compared to no internal termination). The voltage swing can be restored by using the LVDS current double
mode (see Table 11).
Table 12. Programming Internal Termination for LVDS Data and Clock
REGISTER ADDRESS
A5 A4 A3 A2
REGISTER DATA
D5 D4 D3 D2
DESCRIPTION
A7
A6
A1
A0
D7
D6
D1
D0
<DATA TERM> Internal termination - Option to terminate the LVDS DATA buffers inside the ADC to improve signal integrity. By
default, internal termination is disabled.
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
No termination Default after reset
325 Ω
200 Ω
125 Ω
170 Ω
120 Ω
100 Ω
75 Ω
<CLK TERM> Internal termination – Option to terminate the LVDS CLK buffers inside the ADC to improve signal integrity. By
default, internal termination is disabled.
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
No termination Default after reset
325 Ω
200 Ω
125 Ω
170 Ω
120 Ω
100 Ω
75 Ω
38
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Parallel CMOS
In this mode, the 12 data outputs and the output clock are available as 3.3-V CMOS voltage levels. Each data
bit and the output clock is available on a separate pin in parallel. By default, the data outputs are valid during the
rising edge of the output clock. The output clock is CLKOUT (pin 5).
Output Clock Position Programmability
In both the LVDS and CMOS modes, the output clock can be moved around its default position. This can be
done using SEN pin 27 (as described in Table 4) or using the serial interface register bits <CLKOUT POSN>.
Using this allows to trade-off the setup and hold times leading to reliable data capture. There also exists an
option to align the output clock edge with the data transition.
Note that programming the output clock position also affects the clock propagation delay times.
Table 13. CLKOUT Position Programing
REGISTER ADDRESS
A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4
<CLKOUT POSN CMOS> – Output clock rising edge programmability in CMOS mode
REGISTER DATA
DESCRIPTION
A7
D3 D2 D1 D0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
1
1
1
1
Default position
Output clock rising edge later by (1/12)Ts
Output clock rising edge later by (3/12)Ts
Output clock rising edge later by (2/12)Ts
<CLKOUT POSN CMOS> – Output clock falling edge programmability in CMOS mode
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
0
1
0
1
0
0
0
0
0
0
0
0
1
1
1
1
Default position
Output clock falling edge later by (1/12)Ts
Output clock falling edge later by (3/12)Ts
Output clock falling edge later by (2/12)Ts
<CLKOUT POSN LVDS> – Output clock rising edge programmability in LVDS mode
0
0
0
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
1
1
1
Default position
Output clock rising edge earlier by (1/12)Ts
Output clock rising edge aligned with data
transition
0
1
1
0
0
0
1
0
0
0
0
0
0
1
1
1
Output clock rising edge aligned with data
transition
<CLKOUT POSN LVDS> – Output clock falling edge programmability in LVDS mode
0
0
0
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
1
0
0
0
0
0
0
0
1
1
1
Default position
Output clock falling edge earlier by (1/12)Ts
Output clock falling edge aligned with data
transition
0
1
1
0
0
0
1
0
0
0
0
1
1
0
0
1
Output clock falling edge aligned with data
transition
Output Data Format
Two output data formats are supported – 2's complement and offset binary. They can be selected using the DFS
(pin 6) or the serial interface register bit <DFS> . In the event of an input voltage overdrive, the digital outputs go
to the appropriate full scale level. For a positive overdrive, the output code is 0xFFF in offset binary output
format, and 0x7FF in 2's complement output format. For a negative input overdrive, the output code is 0x0000 in
offset binary output format and 0x800 in 2's complement output format.
39
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
Output Timing
For the best performance at high sampling frequencies, ADS5525 uses a clock generator circuit to derive
internal timing for ADC. This results in optimal setup and hold times of the output data and 50% output clock
duty cycle for sampling frequencies from 80 MSPS to 170 MSPS. See Table 14 for timing information above 80
MSPS.
(1)
Table 14. Timing Characteristics (80 MSPS to 170 MSPS)
tsu DATA SETUP TIME, ns
th DATA HOLD TIME, ns
TYP
tPDI CLOCK PROPAGATION DELAY, ns
Fs, MSPS
MIN
TYP
MAX
MIN
MAX
MIN
TYP
MAX
DDR LVDS
150
1.6
2.0
3.6
2.1
2.5
4.1
0.6
0.8
1.6
1.1
1.3
2.1
4.3
4.5
4.7
5
5.7
5.9
6.7
130
5.2
5.7
80
PARALLEL CMOS
150
130
80
2.8
3.3
6
3.6
4.1
7
1.2
1.7
3.7
1.6
2.1
4.1
1.7
1.1
2.5
1.9
12
3.3
2.7
10.8
13.2
(1) Timing parameters are specified by design and characterization and not tested in production.
Below 80 MSPS, the setup and hold times do not scale with the sampling frequency. The output clock duty cycle
also progressively moves away from 50% as the sampling frequency is reduced from 80 MSPS.
See Table 15 for detailed timings at sampling frequencies below 80 MSPS. Figure 49 shows the clock duty cycle
across sampling frequencies in the DDR LVDS and CMOS modes.
(1)
Table 15. Timing Characteristics (1 MSPS to 80 MSPS)
tsu DATA SETUP TIME, ns
MIN TYP MAX
th DATA HOLD TIME, ns
TYP
tPDI CLOCK PROPAGATION DELAY, ns
Fs, MSPS
MIN
1.6
MAX
MIN
TYP
5.7
12
MAX
DDR LVDS
1 to 80
3.6
PARALLEL CMOS
1 to 80
6
3.7
(1) Timing parameters are specified by design and characterization and not tested in production.
100
90
80
70
60
DDR LVDS
50
40
CMOS
30
20
10
0
0
20
40 60
80 100 120 140 160 180
Sampling Frequency − MHz
Figure 49. Output Clock Duty Cycle (typical) vs Sampling Frequency
The latency of ADS5525 is 14 clock cycles from the sampling instant (input clock rising edge). In the LVDS
mode, the latency remains constant across sampling frequencies. In the CMOS mode, the latency is 14 clock
cycles above 80 MSPS and 13 clock cycles below 80 MSPS.
40
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
DEFINITION OF SPECIFICATIONS
Analog Bandwidth
The analog input frequency at which the power of the fundamental is reduced by 3 dB with respect to the low
frequency value.
Aperture Delay
The delay in time between the rising edge of the input sampling clock and the actual time at which the sampling
occurs.
Aperture Uncertainty (Jitter)
The sample-to-sample variation in aperture delay.
Clock Pulse Width/Duty Cycle
The duty cycle of a clock signal is the ratio of the time the clock signal remains at a logic high (clock pulse width)
to the period of the clock signal. Duty cycle is typically expressed as a percentage. A perfect differential
sine-wave clock results in a 50% duty cycle.
Maximum Conversion Rate
The maximum sampling rate at which certified operation is given. All parametric testing is performed at this
sampling rate unless otherwise noted.
Minimum Conversion Rate
The minimum sampling rate at which the ADC functions.
Differential Nonlinearity (DNL)
An ideal ADC exhibits code transitions at analog input values spaced exactly 1 LSB apart. The DNL is the
deviation of any single step from this ideal value, measured in units of LSBs
Integral Nonlinearity (INL)
The INL is the deviation of the ADC’s transfer function from a best fit line determined by a least squares curve fit
of that transfer function, measured in units of LSBs.
Gain Error
The gain error is the deviation of the ADC’s actual input full-scale range from its ideal value. The gain error is
given as a percentage of the ideal input full-scale range.
Offset Error
The offset error is the difference, given in number of LSBs, between the ADC’s actual average idle channel
output code and the ideal average idle channel output code. This quantity is often mapped into mV.
Temperature Drift
The temperature drift coefficient (with respect to gain error and offset error) specifies the change per degree
Celsius of the parameter from TMIN to TMAX. It is calculated by dividing the maximum deviation of the parameter
across the TMIN to TMAX range by the difference TMAX–TMIN
.
41
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
DEFINITION OF SPECIFICATIONS (continued)
Signal-to-Noise Ratio
SNR is the ratio of the power of the fundamental (PS) to the noise floor power (PN), excluding the power at dc
and the first nine harmonics.
P
P
s
SNR + 10Log10
N
(3)
SNR is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the
reference, or dBFS (dB to full scale) when the power of the fundamental is extrapolated to the converter’s
full-scale range.
Signal-to-Noise and Distortion (SINAD)
SINAD is the ratio of the power of the fundamental (PS) to the power of all the other spectral components
including noise (PN) and distortion (PD), but excluding dc.
P
s
SINAD + 10Log10
P
) P
N
D
(4)
SINAD is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the
reference, or dBFS (dB to full scale) when the power of the fundamental is extrapolated to the converter’s
full-scale range.
Effective Number of Bits (ENOB)
The ENOB is a measure of a converter’s performance as compared to the theoretical limit based on quantization
noise.
SINAD * 1.76
ENOB +
6.02
(5)
(6)
Total Harmonic Distortion (THD)
THD is the ratio of the power of the fundamental (PS) to the power of the first nine harmonics (PD).
P
P
s
THD + 10Log10
N
THD is typically given in units of dBc (dB to carrier).
Spurious-Free Dynamic Range (SFDR)
The ratio of the power of the fundamental to the highest other spectral component (either spur or harmonic).
SFDR is typically given in units of dBc (dB to carrier).
Two-Tone Intermodulation Distortion
IMD3 is the ratio of the power of the fundamental (at frequencies f1 and f2) to the power of the worst spectral
component at either frequency 2f1–f2 or 2f2–f1. IMD3 is either given in units of dBc (dB to carrier) when the
absolute power of the fundamental is used as the reference, or dBFS (dB to full scale) when the power of the
fundamental is extrapolated to the converter’s full-scale range.
DC Power Supply Rejection Ratio (DC PSRR)
The DC PSSR is the ratio of the change in offset error to a change in analog supply voltage. The DC PSRR is
typically given in units of mV/V.
42
Submit Documentation Feedback
ADS5525
www.ti.com
SLWS191–JULY 2006
DEFINITION OF SPECIFICATIONS (continued)
AC Power Supply Rejection Ratio (AC PSRR)
AC PSRR is the measure of rejection of variations in the supply voltage of the ADC. If ∆VSUP is the change in
the supply voltage and ∆VOUT is the resultant change in the ADC output code (referred to the input), then
DVOUT
PSRR = 20Log10
(Expressed in dBc)
DVSUP
(7)
Common Mode Rejection Ratio (CMRR)
CMRR is the measure of rejection of variations in the input common-mode voltage of the ADC. If ∆Vcm is the
change in the input common-mode voltage and ∆VOUT is the resultant change in the ADC output code (referred
to the input), then
DVOUT
10
CMRR = 20Log
(Expressed in dBc)
DVCM
(8)
Voltage Overload Recovery
The number of clock cycles taken to recover to less than 1% error for a 6-dB overload on the analog inputs. A
6-dBFS sine wave at Nyquist frequency is used as the test stimulus.
43
Submit Documentation Feedback
PACKAGE OPTION ADDENDUM
www.ti.com
20-Jul-2006
PACKAGING INFORMATION
Orderable Device
Status (1)
Package Package
Pins Package Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)
Qty
Type
QFN
QFN
Drawing
ADS5525IRGZR
ADS5525IRGZT
PREVIEW
PREVIEW
RGZ
48
48
2500
250
TBD
TBD
Call TI
Call TI
Call TI
Call TI
RGZ
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
Addendum-Page 1
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications,
enhancements, improvements, and other changes to its products and services at any time and to discontinue
any product or service without notice. Customers should obtain the latest relevant information before placing
orders and should verify that such information is current and complete. All products are sold subject to TI’s terms
and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI
deems necessary to support this warranty. Except where mandated by government requirements, testing of all
parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for
their products and applications using TI components. To minimize the risks associated with customer products
and applications, customers should provide adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right,
copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process
in which TI products or services are used. Information published by TI regarding third-party products or services
does not constitute a license from TI to use such products or services or a warranty or endorsement thereof.
Use of such information may require a license from a third party under the patents or other intellectual property
of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of information in TI data books or data sheets is permissible only if reproduction is without
alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction
of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for
such altered documentation.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that
product or service voids all express and any implied warranties for the associated TI product or service and
is an unfair and deceptive business practice. TI is not responsible or liable for any such statements.
Following are URLs where you can obtain information on other Texas Instruments products and application
solutions:
Products
Applications
Audio
Amplifiers
amplifier.ti.com
www.ti.com/audio
Data Converters
dataconverter.ti.com
Automotive
www.ti.com/automotive
DSP
dsp.ti.com
Broadband
Digital Control
Military
www.ti.com/broadband
www.ti.com/digitalcontrol
www.ti.com/military
Interface
Logic
interface.ti.com
logic.ti.com
Power Mgmt
Microcontrollers
power.ti.com
Optical Networking
Security
www.ti.com/opticalnetwork
www.ti.com/security
www.ti.com/telephony
www.ti.com/video
microcontroller.ti.com
Low Power Wireless www.ti.com/lpw
Telephony
Video & Imaging
Wireless
www.ti.com/wireless
Mailing Address:
Texas Instruments
Post Office Box 655303 Dallas, Texas 75265
Copyright 2006, Texas Instruments Incorporated
相关型号:
ADS5527IRGZ25
1-CH 12-BIT PROPRIETARY METHOD ADC, PARALLEL ACCESS, PQCC48, 7 X 7 MM, GREEN, PLASTIC, QFN-48
TI
©2020 ICPDF网 联系我们和版权申明