Cypress CY25566 User Manual

Spread spectrum clock generator, Features, Applications

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Spread Spectrum Clock Generator

CY25566

Cypress Semiconductor Corporation

3901 North First Street

San Jose

CA 95134

408-943-2600

Document #: 38-07429 Rev. *B

Revised October 26, 2005

Features

• 25- to 200-MHz operating frequency range
• Wide range of spread selections (9)
• Accepts clock or crystal inputs
• Provides four clocks

— SSCLK1a

— SSCLK1b

— SSCLK2

— REFOUT

• Low-power dissipation

— 3.3V = 70 mW (typical @ 40 MHz, no load)

• Center spread modulation
• Low cycle-to cycle jitter
• 16-pin SOIC package

Applications

• High-resolution VGA controllers
• LCD panels and monitors
• Printers and MFPs

Benefits

• Peak EMI reduction by 8 to 16 dB
• Fast time to market
Cost reduction

Block Diagram

Pin Configuration

1

16

15

14

13

9

8

7

6

5

4

3

2

10

11

12

XIN/CLKIN

REFOFF

VDD

VSS

S2

S3

SSCLK1a

REFOUT

SSCLK1b

SSCC

VSS

S1

S0

VSS

SSCLK2

XOUT

C

Y

25566

3

PD

REFERENCE

DIVIDER

Loop
Filter

1

4

MODULATION

CONTROL

INPUT

DECODER

LOGIC

FEEDBACK

DIVIDER

vco

DIVIDER

&

MUX

16

5

CP

SSCLK1a

S0

S1

12

13

10

8

20 K

20 K

20 K

20 K

SSCC

VDD

VSS

Xout

Xin/

CLK

VDD

VDD

VSS

VSS

300K

14

11

VSS

VSS

RANGE

CONTROL

6

7

S3

S2

9

15

SSCLK1b

SSCLK2

/2

2

REFOUT

REFOFF

[+] Feedback

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