LG1625AXF Laser Driver
Test Circuit
MK MK VSS –5.2 V VSS –5.2 V
Data Sheet
June 1999
50 Ω
+
DATA
GENERATOR
12
11
MK
18
MK
21
VPRE
0.1 µF 2
24
VMOD
VIN LG1625AXF
IOUT
VSS3
VSS2
20
VTH
VSS1
19
VTH
IPRE IF VPRE > –5.0 V
16
IMOD
50 Ω
xx
50 Ω
SCOPE
20 Ω
7
0.1 µF
20 Ω
1Ω
IMOD
MONITOR
1Ω
IPRE
MONITOR
Notes:
GND pins 3, 4, 5, 8, 9, 10, 14, 15, 17.
VSS1 pins 1, 6, 13, 22, 23.
VSS –5.2 V
Figure 5. LG1625AXF Typical Test Circuit
5-7876(F)r.1
LG1625AXF Application Notes
s VSS bypass capacitors should be mounted close to the package.
s 5000 Ω potentiometer is typically set for 2500 Ω. This establishes an approximate –1.3 V VTH which will track
with VSS.
s Mark density (MK and MK) outputs are terminated with 1 kΩ pull-up resistors.
s IMOD and IPRE can be measured and used to control VMOD and VPRE.
6
Lucent Technologies Inc.