SM8706CV [NPC]

Clock Generator,;


型号：	SM8706CV
厂家：	NIPPON PRECISION CIRCUITS INC
描述：	Clock Generator,
文件：	总8页 (文件大小：98K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

SM8706B/C

Clock Generator with Dual PLLs

OVERVIEW

The SM8706B/C is a dual-PLL clock generator IC that generates 3 different system clocks using 6 outputs,

derived from a 36.8640MHz master clock. Each PLL loop ﬁlter and crystal oscillator circuit are built-in,

requiring no external components, and generate the independent 384fs/768fs audio system clocks, 27/54MHz

video system clocks, and 16.9344/33.8688MHz signal processor clocks necessary for DVD player/recorder

applications. Each system output can be stopped using control pins. The device also is compatible with

44.1/48kHz sampling frequencies, and the sampling frequency can also be switched during operation without

generating any output spike noise. The control method is described in "Table 1. Sampling frequency and output

clock frequency" on page 6.

FEATURES

PINOUT

(Top view)

^ꢀDifference between SM8706B and SM8706C

• SM8706B

- MO1/2 output:

MO1 = 27MHz, MO2 = 54MHz

• SM8706C

- MO1/2 output:

MO1 = 54MHz, MO2 = 27MHz

- Pb free

^ꢀ36.8640MHz master clock (internal PLL reference

clock)

^ꢀPLL loop ﬁlter built-in

^ꢀCrystal oscillator circuit built-in

^ꢀGenerated clocks

VDD1

VSS1

MO1

MO2

VDD2

VSS2

XTI

SO2

FSEL

SO1

VDD3

VSS3

AO2

AO1

XTO

• Video system output: 27MHz, 54MHz

• Audio system output: 384fs, 768fs

• Signal processor system output: 16.9344MHz,

33.8688MHz

PACKAGE DIMENSIONS

^ꢀSupported sampling frequency fs: 44.1/48kHz

^ꢀLow jitter output: 40ps typ. (1-sigma, 25pF load)

^ꢀSupply voltage: 3.3V 0.3V

^ꢀ16-pin VSOP package

(Unit: mm)

Weight: 0.07g

APPLICATIONS

^ꢀDVD players/recorders

^ꢀDVD car navigation system

ORDERING INFORMATION

+ 0.1

- 0.05

0.15

0.275typ

5.1 0.2

Device

Package

SM8706BV

SM8706CV

16-pin VSOP

0 to 10

0.65

0.10

+ 0.1

0.5 0.2

0.22

- 0.05

0.12

NIPPON PRECISION CIRCUITS INC.—1

SM8706B/C

BLOCK DIAGRAM

FSEL

Reference

Divider 0

Phase

Detector 0

Charge

Pump 0

AO1

AO2

LPF 0

VCO 0

XTI

X'tal

OSC

XTO

Loop

Divider 0

(PLL 0)

SO1

SO2

Control

Logic

Reference

Divider 1

Phase

Detector 1

Charge

Pump 1

LPF 1

VCO 1

Loop

Divider 1

MO1

MO2

(PLL 1)

PIN DESCRIPTION

Number

Name

VDD1

VSS1

MO1

MO2

VDD2

VSS2

XTI

I/O

–

Description

Supply 1 for digital block

Ground 1 for digital block

–

Video system output 1 (SM8706B: 27MHz ﬁxed, SM8706C: 54MHz ﬁxed)

Video system output 2 (SM8706B: 54MHz ﬁxed, SM8706C: 27MHz ﬁxed)

Supply 2 for analog block

–

Ground 2 for analog block

Crystal oscillator connection or external clock input

Crystal oscillator connection

XTO

–

AO1

Audio system output 1 (384fs output)

AO2

Audio system output 2 (768fs output)

VSS3

VDD3

SO1

Ground 3 for digital block

–

Supply 3 for digital block

Signal processor system output 1 (16.9344MHz ﬁxed)

Sampling frequency select

FSEL = HIGH: fs = 48kHz

FSEL = LOW: fs = 44.1kHz

(with internal pull-up resistor, Schmitt-trigger input)

FSEL

SO2

Signal processor system output 2 (33.8688MHz ﬁxed)

Chip enable (HIGH = Enable, LOW = Disable)

NIPPON PRECISION CIRCUITS INC.—2

SM8706B/C

Note: Unless otherwise noted, VDD applies to VDD1, VDD2, and VDD3. Similarly, VSS applies to VSS1,

VSS2, and VSS3.

SPECIFICATIONS

Absolute Maximum Ratings

Parameter

Symbol

Condition

Rating

Unit

Supply voltage range

, V , V

DD1 DD2 DD3

− 0.3 to + 6.5

– V

DD1

DD2

DD3

Supply voltage deviation

0.1

– V

DD3

DD2

Input voltage range

− 0.3 to V + 0.3

Output voltage range

Power dissipation

− 0.3 to V + 0.3

OUT

165

°C

Storage temperature range

− 55 to + 125

stg

Recommended Operating Conditions

= V

= 0V unless otherwise noted.

SS1

SS2

SS3

Rating

Parameter

Symbol

Condition

Unit

min

+ 3.0

–

typ

–

max

+ 3.6

1, 2, 3

Supply voltage ranges

, V , V

DD1 DD2 DD3

Output load capacitance 1

Output load capacitance 2

MO1, SO1, SO2 outputs

–

All outputs excluding MO1,

SO1, SO2, XTO

–

Master clock frequency

When using crystal oscillator

–

36.8640

–

MHz

XTAL

Operating temperature range

– 40

+ 85

°C

opr

1. The supply voltage is deﬁned relative to V = 0V

2. The supply voltages applied on VDD1, VDD2, and VDD3 should be derived from a common supply source.

3. If the supply voltages on VDD1, VDD2, and VDD3 are from different sources, they should be applied simultaneously. The SM8706B/C may be dam-

aged if the supply voltage timing is different.

DC Electrical Characteristics

= 36.8640MHz, V = 3.3V 0.3V, V = 0V, Ta = – 40 to + 85 °C unless otherwise noted.

DD SS

XTAL

Rating

typ

Parameter

Symbol

Condition

Unit

min

–

max

= 3.3V, Ta = 25°C,

fs = 48kHz, Crystal oscillator,

no load on all outputs

Current consumption

HIGH-level input voltage

LOW-level input voltage

0.8 V

–

FSEL, CE, XTI, V = 3.3V

–

0.2 V

HIGH-level input current

FSEL, CE, V = V

−

µA

IH1

LOW-level input current

HIGH-level input current

LOW-level input current

FSEL, CE, V = 0V

– 100

–

IL1

XTI, V = V

−

IH2

XTI, V = 0V

– 40

IL2

All outputs excluding XTO,

= − 2mA

HIGH-level output voltage

LOW-level output voltage

− 0.4

–

All outputs excluding XTO,

= 2mA

–

0.4

1. FSEL and CE pins have Schmitt-trigger input and built-in pull-up resistor.

NIPPON PRECISION CIRCUITS INC.—3

SM8706B/C

AC Electrical Characteristics

= 36.8640MHz, V = 3.3V 0.3V, V = 0V, Ta = – 40 to + 85 °C unless otherwise noted.

DD SS

XTAL

Rating

typ

Parameter

Symbol

Condition

Unit

min

max

External input clock frequency

XTI, applies to external clock input use only

–

36.8640

–

MHz

XTI

MO1, SO1, SO2, C = 25 pF, transition

–

2.0

–

between V = 0.2V and V = 0.8V

Output clock rise time

Outputs excluding MO1, SO1, SO2, and XTO,

C = 15pF, transition between V = 0.2V

and V = 0.8V

MO1, SO1, SO2, C = 25pF, transition

between V = 0.8V and V = 0.2V

Output clock fall time

Outputs excluding MO1, SO1, SO2, and XTO,

C = 15pF, transition between V = 0.8V

and V = 0.2V

MO1, SO1, SO2, Ta = 25°C, C = 25pF,

–

= 0.5V

jitter

(1-sigma)

Output clock jitter

Outputs excluding MO1, SO1, SO2, and XTO,

Ta = 25°C, C = 15pF, V = 0.5V

MO1, SO1, SO2, Ta = 25°C, C = 25pF,

= 0.5V

Output clock duty cycle

Outputs excluding MO1, SO1, SO2, and XTO,

Ta = 25°C, C =15 pF, V = 0.5V

Settling time

All outputs excluding XTO

–

µs

2,4

Power-up time

1. When using an external clock input, the XTI duty should be 50% with 3.3V clock signal amplitude level. The input signal voltage should not exceed the

absolute maximum rating, otherwise damage may occur.

2. The numeric values are measured values obtained using the circuit in Figure 1 and the NPC standard evaluation board.

3. The numeric values are measured values obtained using the circuit in Figure 2 and the NPC standard evaluation board.

4. This is the time, after the supply is turned ON from the OFF state, until the output clock reaches 0.1% of the speciﬁed frequency.

36.864MHz

Oscilloscope

Active Probe

DUT

(Infinium

(HP1152A)

HP54845A)

Jitter

Measurement

System

Oscilloscope

(HP54720D

+HP54721A)

Active Probe

(HP54701A)

DUT

DUT:Device under testing

Frequency &

Time Interval

Analyzer

(ASA, M1)

Passive Probe

(HP10435A)

DUT:Device under testing

(HP5371A)

Figure 1. Measurement circuit 1

Figure 2. Measurement circuit 2

NIPPON PRECISION CIRCUITS INC.—4

SM8706B/C

FUNCTIONAL DESCRIPTION

36.8640MHz Master Clock

The SM8706B/C 36.8640MHz master clock circuit is conﬁgured, as shown in Figure 3, with the crystal oscil-

lator element connected between XTI (pin 7) and XTO (pin 8).

Alternatively, the 36.8640MHz master clock can be supplied from an external master clock input on XTI, as

shown in Figure 4.

If an external input clock on XTI is used, it is recommended that the frequency be 36.8640MHz, with 50%

duty, and 3.3V voltage amplitude level.

Furthermore, when using an external clock input, the input signal voltage should not exceed the absolute max-

imum rating, otherwise damage may occur.

XTI (Pin 7)

Internal

Circuits

Oscillator

Control

Logic

XTO (Pin 8)

C1, C2 = 5 to 33pF

MO1 (Pin 3)

MO2 (Pin 4)

Figure 3. Crystal oscillator connection

External Clock

Open

XTI (Pin 7)

Internal

Circuits

Oscillator

Control

Logic

XTO (Pin 8)

MO1 (Pin 3)

MO2 (Pin 4)

Figure 4. External clock input

NIPPON PRECISION CIRCUITS INC.—5

SM8706B/C

Sampling Frequency and Output Clock Frequency

The SM8706B/C sampling frequency fs can be switched between 44.1kHz when FSEL (pin 14) is LOW, and

48kHz when FSEL is HIGH. The audio outputs (AO1 and AO2) are a 384fs and 768fs frequency clock, respec-

tively, where fs is determined by the setting on FSEL. In addition, the signal processor outputs (SO1 and SO2)

are a 16.9344MHz and 33.8688MHz frequency clock, respectively, derived from the master clock. The video

system clocks are output on pins MO1 [27/54MHz (SM8706B/SM8706C)], and MO2 [54/27MHz

(SM8706B/SM8706C)].

When CE (Pin16) is HIGH, the chip is enabled. When LOW, the chip is disabled. When disabled, all output go

LOW and all internal circuits stop operating. When CE goes LOW to HIGH, the chip moves from disabled to

enabled, the time taken until the output frequency clocks stabilize is a maximum of 5ms.

The SM8706B/C output clock frequencies that can be selected is shown in Table 1. The output clock response

timing relative to the CE setting is shown in Figure 5.

Table 1. Sampling frequency and output clock frequency (36.8640MHz master clock frequency)

Output clock frequency [MHz]

Sampling

frequency

fs [kHz]

FSEL

(Pin 14)

(Pin 16)

MO1 (Pin 3)

MO2 (Pin 4)

AO1

(Pin 9)

AO2

(Pin 10)

SO1

(Pin 13)

SO2

(Pin 15)

SM8706B SM8706C SM8706B SM8706C

LOW

HIGH

LOW

HIGH

44.1

16.9344

18.4320

33.8688

36.8640

16.9344

33.8688

27.0000

54.0000

27.0000

44.1

5ms

(max)

AO1/AO2

SO1/SO2

MO1/MO2

Figure 5. CE switching response

NIPPON PRECISION CIRCUITS INC.—6

SM8706B/C

Spike Noise Prevention Function

The SM8706B/C has a spike noise prevention circuit that operates to prevent the generation of spike noise on

the audio output clocks when the sampling frequency is switched using FSEL.

The AO1 and AO2 output clock state before and after FSEL changes state is shown in Figure 6.

When FSEL is switched LOW to HIGH or switched HIGH to LOW, the spike noise circuit stops the AO1 and

AO2 outputs for a maximum of 1µs to prevent output spike noise, and then the outputs change to reﬂect the

FSEL setting.

fs = 48kHz

fs = 44.1kHz

FSEL

AO1

AO2

1µs (max)

Figure 6. Spike noise prevention circuit timing

(sampling frequency fs = 48kHz → fs = 44.1kHz switching example)

Sampling Frequency Switching Settling Time

The clock output response timing when the sampling frequency fs is switched using FSEL is shown in Figure

7. The SM8706B/C has a built-in spike noise prevention circuit. As a result, the AO1 and AO2 outputs stop for

a ﬁxed interval after FSEL changes state, as described above, and hence the settling time t for the audio output

clock when switching the sampling frequency is 1µs maximum.

0.8VDD

FSEL

0.2VDD

AO1

AO2

fs = 44.1kHz

fs = 48kHz

fs = 44.1kHz

27.0000MHz

/54MHz

MO1

MO2

SO1

SO2

16.9344MHz

/33.8688MHz

Figure 7. Output signal switching timing

NIPPON PRECISION CIRCUITS INC.—7

SM8706B/C

NIPPON PRECISION CIRCUITS INC. reserves the right to make changes to the products described in this data sheet in order to

improve the design or performance and to supply the best possible products. Nippon Precision Circuits Inc. assumes no responsibility for

the use of any circuits shown in this data sheet, conveys no license under any patent or other rights, and makes no claim that the circuits

are free from patent infringement. Applications for any devices shown in this data sheet are for illustration only and Nippon Precision

Circuits Inc. makes no claim or warranty that such applications will be suitable for the use speciﬁed without further testing or modiﬁcation.

The products described in this data sheet are not intended to use for the apparatus which inﬂuence human lives due to the failure or

malfunction of the products. Customers are requested to comply with applicable laws and regulations in effect now and hereinafter,

including compliance with export controls on the distribution or dissemination of the products. Customers shall not export, directly or

indirectly, any products without ﬁrst obtaining required licenses and approvals from appropriate government agencies.

NIPPON PRECISION CIRCUITS INC.

4-3, Fukuzumi 2-chome, Koto-ku,

Tokyo 135-8430, Japan

Telephone: +81-3-3642-6661

Facsimile: +81-3-3642-6698

http://www.npc.co.jp/

Email: sales@npc.co.jp

NC0106BE 2002.05

NIPPON PRECISION CIRCUITS INC.—8

SM8706CV [NPC]

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