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Application Notes

The receiver converts the incident optical power to

a photocurrent via a high performance avalanche

photodiode (APD). The photocurrent can be monitored

via the differential voltage across the two VPM+ and

VPM- output pins. It is important to note that the

common mode voltage (i.e. DC voltages at PM+ and

VPM-) is high (-60V typical). The APD bias voltage is

temperature compensated to ensure stable operation

over the entire operating temperature range. The APD

bias voltage is also available as an output via the VPD

output. The maximum current that this output can

source is 1mA.

The signal detect circuit monitors the level of the

incoming optical signal and generates a logic LOW signal

when an insufficient photocurrent is produced.

Both differential DATA+ and DATA outputs (also

SIGNAL DETECT+ and SIGNAL DETECT- if the PECL

option is chosen) are open emitter PECL levels

requiring termination (50Ω to V

GRD is recommended). Both differential outputs

should be terminated in the same manner, even if

only one is used.

If the TTL option is chosen for the SIGNAL DETECT

outputs, no termination resistor should be used.

The power supply line should be wellfiltered. The

power supply should be bypassed by 0.01 or 0.1μF

ceramic chip placed as close to the receiver module

as possible.

Related Transmitter & Receiver Modules

STX-12

: OC-12/STM-4 Transmitter (multi-sourced 20-pin DIP)

SRX-12

: OC-12/STM-4 Receiver without Clock Recovery, ECL SIGNAL DETECT (multi-sourced 20-pin DIP)

SRX-12-L

: OC-12/STM-4 Receiver without Clock Recovery, TTL SIGNAL DETECT (multi-sourced 20-pin DIP)

SRC-12

: OC-12/STM-4 Receiver with Clock Recovery (multi-sourced 20-pin DIP)

SRC-12-S

: OC-12/STM-4 Receiver with Clock Recovery (24-pin DIP, compatible with Sumitomo SDT8712-RD)

SRX

The pigtail length from the

package edge is 1.0 meter typical.

Ordering Information

SRX12-APD

R3. 2008.04.30

3

APD

VPM-

VPM+

VPD

OUT

APD Bias

220Ω

10kΩ

10kΩ

Supply

Package Outline

Dimensions in inches [mm]

Default tolerances:

.xxx = ± .005”, .xx = ± .01”

Type

RX only 5V= 8

Temperature Range

Receivers

Wavelength Range

Rx 1100-1600nm APD

-40 ~85˚C= I

0~70˚C= H

0

0

0

2

X

R

2

8

1

Connector Type &

Option

Pigtail FC, SD-TTL= PA

Pigtail ST, SD-TTL= PB

Pigtail SC, SD-TTL= P5

Pigtail FC, SD-PECL= PC

Pigtail ST, SD-PECL= PD

Pigtail SC, SD-PECL= P4