SLK2501

OC48/24/12/3 SONET/SDH MULTIRATE TRANSCEIVER

SLLS502A – OCTOBER 2001 – REVISED NOVEMBER 2001

5

POST OFFICE BOX 655303

Terminal Functions(Continued)

control/status pins

TERMINAL

TYPE

DESCRIPTION

NAME

NO.

TYPE

DESCRIPTION

RSEL0, RSEL1

39

38

TTL input (with pulldown)

Data rate configuration pins. Put the device under one of the four data rate operations:

OC-48, OC-24, OC-12 or OC-3.

CONFIG0,

CONFIG1

17

18

TTL input (with pulldown)

Configuration pins. Put the device under one of the four operation modes: TX only, RX

only, transceiver, or repeater mode.

PRE1,

PRE2

4

5

TTL input (with pulldown)

Programmable preemphasis control. Combinations of these two bits can be used to

optimize serial data transmission.

RESET

48

TTL input

TXFIFO and LOL reset pin. Low is reset and high is normal operation.

AUTO_DETECT

34

TTL input (with pulldown)

Data rate autodetect enable. Enable the autodetection function for different data rates.

LLOOP

53

TTL input (with pulldown)

Local loopback enable. When high, the serial output is internally looped back to its

serial input

RLOOP

54

TTL input (with pulldown)

Remote loopback enable. When high, the serial input is internally looped back to its

serial output with the timing extracted from the serial data.

ENABLE

44

TTL input (with pullup)

Standby enable. When this pin is held low, the device is disabled for IDDQ testing.

When high, the device operates normally.

FRAME_EN

27

TTL input (with pullup)

Frame sync enable. When this pin is asserted high, the frame synchronization circuit

for byte alignment is turned on.

PRBSEN

41

TTL input (with pulldown)

PRBS testing enable. When this pin is asserted high, the device is put into the PRBS

testing mode.

SIGDET

20

TTL input (with pulldown)

Signal detect. This pin is generally connected to the output of an optical receiver. This

signal may be active high or active low depending on the optical receiver. The SIGDET

input is XORed with the PS pin to select the active state. When SIGDET is in the

inactive state, data is processed normally. When activated, indicating a loss of signal

event, the transmitter transmits all zeroes and force the LOS signal to go high.

PS

21

TTL input (with pulldown)

Polarity select. This pin, used with the SIGDET pin, sets the polarity of SIGSET. When

high, SIGDET is an active low signal. When low, SIGDET is an active high signal.

RX_MONITOR

47

TTL input (with pulldown)

RX parallel data monitor in repeater mode. This pin is only used when the device is put

under repeater mode. When high, the RX demux circuit is enabled and the parallel data

is presented. When low, the demux is shut down to save power.

LCKREFN

24

TTL input (with pullup)

Lock to reference. When low, RXCLKP/N output is forced to lock to REFCLK. When

high, RXCLKP/N is the divided down clock extracted from the receive serial data.

LOOPTIME

51

TTL input (with pulldown)

Loop timing mode. When high, the PLL for clock synthesizer is bypassed. The

recovered clock timing is used to send the transmit data.

TESTEN

43

TTL input (with pulldown)

Production test mode enable. This pin should be left unconnected or tied low.

RATEOUT0,

RATEOUT1

37

36

TTL output

Autorate detection outputs. When AUTO_DETECT is high, the autodetection circuit

generates these two bits to indicate the data rates for the downstream device.

LOL

45

TTL output

Loss of lock. When the clock recovery loop has locked to the input data stream and the

phase differs by less than 100 ppm from REFCLK then LOL is high. When the phase of

the input data stream differs by more than 100 ppm from REFCLK, then LOL is low. If

the difference is too big (> 500 ppm), the LOL output is not valid.

LOS

46

TTL output

Loss of signal. When no transitions appear on the input data stream for more than

2.3

µs, a loss of signal occurs and LOS goes high. The device also transmits all zeroes

downstream using REFCLK as its clock source. When a valid SONET signal is

received the LOS signal goes low.