AD809

REV. A

–3–

Table I.

MUX Input

Input Selected

TTL “0”

CLKIN/CLKINN

TTL “1”

PECLIN/PECLINN

Table II. Applying a PECL/ECL or CMOS/TTL Reference

Input to the AD809

Input Reference

AD809 Configuration

PECL/ECL Differential

Apply the valid PECL–level reference

frequency to Pins 13 and 12.

AD809 frequency synthesizer ignores

the input at Pin 10.

TTL/CMOS

Apply the reference frequency to

Single-Ended

Pin 10.

(Pins 9 and 16). The AD809 senses

the common-mode signal at these pins

as less than valid PECL and selects the

TTL/CMOS input as active.

AD809 Phase Skew

The AD809 output is in phase with the input. The falling edge

at Pin 4, CLKOUTN, occurs 700 ps before the rising edge at

Pin 10, TTL/CMOSIN at 27

°C. The phase skew remains rela-

tively constant over temperature. Refer to Table III for phase

skew data.

Table III. Phase Skew vs. Temperature

Skew (CLKOUTN, Pin 4, Relative to

Temperature

TTL/CMOSIN, Pin 10 Measured in

( C)

ps at Package Pins)

–35

–1000

–20

–950

0

–850

10

–750

30

–700

50

–600

70

–450

80

–450

90

–350

100

–250

PIN DESCRIPTIONS

Pin

No.

Mnemonic

Description

1

PECLINN

Differential 155 MHz Input

2

PECLIN

Differential 155 MHz Input

4

CLKOUTN

Differential 155 MHz Output

5

CLKOUT

Differential 155 MHz Output

7

CF1

Loop Damping Capacitor

8

CF2

Loop Damping Capacitor

10

TTL/CMOSIN TTL/CMOS Reference Clock Input

11

12

CLKINN

PECL Differential Reference Clock Input

13

CLKIN

PECL Differential Reference Clock Input

14

15

MUX

Input Signal Mux Control Input

16

PIN CONFIGURATION

14

13

12

11

16

15

10

9

8

1

2

3

4

7

6

5

TOP VIEW

(Not to Scale)

AD809

PECLINN

CLKIN

MUX

PECLIN

CLKOUTN

TTL/CMOSIN

CLKINN

CLKOUT

CF1

CF2

WARNING!

ESD SENSITIVE DEVICE

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily

accumulate on the human body and test equipment and can discharge without detection.

Although the AD809 features proprietary ESD protection circuitry, permanent damage may

occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD

precautions are recommended to avoid performance degradation or loss of functionality.