3

SY88905

Micrel

DETAILED DESCRIPTION

The SY88905 is an integrated control circuit for laser

diode modules intended for high-frequency fiber-optic

applications. The device is designed to operate with the

SY88902 laser diode driver providing Automatic Power

Control (APC) which provides bias current control and

monitor diode interface. The device also interfaces with the

SY88903 high-speed limiting amplifier providing chatter-free

Loss of Signal function.

Laser Diode Supply Current

The SY88905 provides the adjustable drive current for

the laser diode, DC bias.

Monitor Diode

The MD pin on the SY88905 provides low frequency

light intensity, laser power out feedback from the monitor

diode in the laser diode package. This feedback is used to

circuit to maintain a near constant power output from the

laser diode.

Symbol

Parameter

Min.

Typ.

Max.

Min.

Typ.

Max.

Min.

Typ. Max. Unit

Conditions

Power Supply Current

—

—

40

—

28

40

—

—

40

mA

No output load

—

—

0.9

—

—

0.9

—

—

0.9

mA

0.5

—

25

0.5

—

25

0.5

—

25

mA

28

—

44

28

37

44

28

—

44

Reference Voltage

2.30

—

3.30

2.30

2.75

3.30

2.30

—

3.30

V

µA

0.95

—

1.35

0.95

1.13

1.35

0.95

—

1.35

V

0.8

—

1.20

0.8

1.0

1.20

0.8

—

1.20

V

Compliance Voltage

0.1

—

1.0

0.1

0.4

1.0

0.1

—

1.0

V

350

—

—

350

500

—

350

—

—

µA

4

—

14

4

—

14

4

—

14

DC ELECTRICAL CHARACTERISTICS

±10%

NOTE:

1.

µA

2.

NOTE:

1. Individual product specifications over-ride general specifications.

TTL DC ELECTRICAL CHARACTERISTICS

±10%

Symbol

Parameter

Min.

Max.

Min.

Max.

Min.

Max.

Unit

Condition

Input HIGH Voltage

2.0

—

2.0

—

2.0

—

V

—

Input LOW Voltage

—

0.8

—

0.8

—

0.8

V

—

Input HIGH Current

—

20

—

20

—

20

—

100

—

100

—

100

Input LOW Current

—

–0.3

—

–0.3

—

–0.3

mA

Input Clamp Voltage

—

–1.2

—

–1.2

—

–1.2

V