SY87701AL

3

Micrel, Inc.

M9999-082107

hbwhelp@micrel.com or (408) 955-1690

Pin Number

Pin Number

SOIC

TQFP

Pin Name

Pin Function

4

2

RDINP

Serial Data Input (Differential PECL): These built-in line receiver inputs are

5

3

RDINN

connected to the differential receive serial data stream. An internal receive PLL

recovers the embedded clock (RCLK) and data (RDOUT) information. The

incoming data rate can be within one of eight frequency ranges depending on the

state of the FREQSEL pins. See “Frequency Selection” table.

7

5

REFCLK

Reference Clock (TTL Inputs): This input is used as the reference for the internal

frequency synthesizer and the “training” frequency for the receiver PLL to keep it

centered in the absence of data coming in on the RDIN inputs.

27

26

CD

Carrier Detect (PECL Input): This input controls the recovery function of the

Receive PLL and can be driven by the carrier detect output of optical modules or

from external transition detection circuitry. When this input is HIGH the input data

stream (RDIN) is recovered normally by the Receive PLL. When this input is LOW

the data on the inputs RDIN will be internally forced to a constant LOW, the data

outputs RDOUT will remain LOW, the Link Fault Indicator output LFIN forced LOW

and the clock recovery PLL forced to look onto the clock frequency generated from

REFCLK.

6

4

FREQSEL1

Frequency Select (TTL Inputs): These inputs select the output clock frequency

8

6

FREQSEL2

range as shown in the “Frequency Selection” table.

9

7

FREQSEL3

3

32

DIVSEL1

Divider Select (TTL Inputs): These inputs select the ratio between the output clock

26

25

DIVSEL2

frequency (RCLK/TCLK) and the REFCLK input frequency as shown in the

“Reference Frequency Selection” table.

17

16

CLKSEL

Clock Select (TTL Inputs): This input is used to select either the recovered clock

of the receiver PLL (CLKSEL = HIGH) or the clock of the frequency synthesizer

(CLKSEL = LOW) to the TCLK outputs.

2

31

LFIN

Link Fault Indicator (TTL Output): This output indicates the status of the input data

stream RDIN. Active HIGH signal is indicating when the internal clock recovery

PLL has locked onto the incoming data stream. LFIN will go HIGH if CD is HIGH

and RDIN is within the frequency range of the Receive PLL (1000ppm).

25

24

RDOUTP

Receive Data Output (Differential PECL): These ECL 100k outputs represent the

24

23

RDOUTN

recovered data from the input data stream (RDIN). This recovered data is specified

against the rising edge of RCLK. These outputs must be terminated with 50

Ω to

22

21

RCLKP

Clock Output (Differential PECL): These ECL 100k outputs represent the

21

20

RCLKN

recovered clock used to sample the recovered data (RDOUT).

19

18

TCLKP

Clock Output (Differential PECL): These ECL 100k outputs represent either the

18

17

TCLKN

recovered clock (CLKSEL = HIGH) used to sample the recovered data (RDOUT) or

the transmit clock of the frequency synthesizer (CLKSEL = LOW). These outputs

must be terminated with 50

Ω toV

outputs are not used.

11

9

PLLSP

Clock Synthesis PLL Loop Filter. External loop filter pins for the clock synthesis

12

10

PLLSN

PLL.

16

15

PLLRP

Clock Recovery PLL Loop Filter. External loop filter pins for the receiver PLL.

15

14

PLLRN

28

27, 28,

1

29, 30

20, 23

19, 22

13, 14

12, 13

GND

Ground

10

1, 8

NC

No Connect

13

11

GNDA

Analog Ground

Note:

PIN DESCRIPTIONS