CXB1818Q Просмотр технического описания (PDF) - Sony Semiconductor

Номер в каталоге

Компоненты Описание

Список матч

CXB1818Q

Laser Diode Driver

Sony Semiconductor 

CXB1818Q

The laser diode alarm output state can be controlled by the alarm signal control pin (Pin 26 MaskSel) for the

optical power output forced shutdown. When the automatic shutdown is conducted and MaskSel pin is left

open, the laser diode alarm output goes High. The laser diode alarm output is kept Low (disable) by connecting

MaskSel pin to VEE.

5. Shutdown and Input Alarm Circuits

These circuits disable both the modulation current and the bias current under various conditions. The function

block diagram for all of the shutdown mechanisms for the circuit is shown in Fig. 5.

The Shutdown circuit has complementary TTL input to disable the output current. Shown below is the desired

truth table for the shutdown function.

SDN

Low

Low

High

High

SDNB

Low

High

Low

High

Output current

Off

On

Off

Off

The Activity detector (In_ALM) circuit is designed to detect the input data edge transition. If there is no input

data transition over a certain period determined by the user (TACT), the Shutdown circuit is enabled, causing

the modulation current and bias current to be shutdown. The Inactive time (TACT) is set by the external

capacitor value between Timer (Pin 17) and VCC. The relation between the Inactive time and Ctimer is shown

in Fig.6.

SDN

SDNB

D

DB

Shutdown

In_ALM

Switch

To modulation and

bias current

Shutdown circuits

Timer ADCDis

Fig.5. Shutdown and In_ALM Functional Block Diagram

6. Others

Pay attention to handling this IC because its electrostatic discharge strength is weak.

The Tset pin (Pin 31) should be connected to VCC through a resistor.

Do not leave this pin open or connect to VCC directly.

– 11 –

Share Link: