ASM3P2811A/B

ASM3P2812A/B

November 2006

ASM3P2814A/B

rev 1.5

Low Power EMI Reduction IC

2 of 11

Notice: The information in this document is subject to change without notice.

Block Diagram

Pin Configuration

Pin Description

Pin#

Pin Name

Type

Description

1

XIN

I

Crystal connection or external frequency input. This pin has dual functions. It can

be connected to either an external crystal or an external reference clock.

2

VSS

P

Ground to entire chip.

3

D_C

I

Digital logic input used to select Down (LOW) or Center (HIGH) spread options.

(Refer Output Frequency Deviation and Spread Option Selection Table).

This pin has an internal pull-up resistor.

4

SRS

I

Spread range select. Digital logic input used to select frequency deviation

(Refer Output Frequency Deviation and Spread Option Selection Table).

This pin has an internal pull-up resistor.

5

ModOUT

O

Spread spectrum clock output

6

FRS

I

Frequency range select. Digital logic input used to select Input frequency range

(Refer Input/Output Frequency Range Selection Table).

This pin has an internal pull-up resistor.

7

VDD

P

Power supply for the entire chip.

8

XOUT

O

Crystal connection. Output connection for an external crystal. If using an external

reference, this pin must be left unconnected.

VSS

XIN

Crystal

Oscillator

Frequency

Divider

Feedback

Divide

Modulation

Phase

Detector

Loop

Filter

VCO

Output

Divider

ModOUT

PLL

VDD

D_C SRS FRS

XOUT

1

2

3

4

5

6

7

8

FRS

XOUT

ModOUT

XIN

VSS

D_C

SRS

VDD

P2811A/B

P2812A/B

P2814A/B