iC-WJB
2.7 V LASER DIODE DRIVER
Rev E1, Page 10/12
2.7..6V
C1
47uF
C3
2nF
R1
GND
1
2
KLD
8
7
6
LD MD
0..2Ω
AMD
CWD
CI
22nF
WDOG
3
CI
IN
C2
100nF
REF
RSET
27kΩ
4
5
ISET
VCC
VMOD
0..1.3V
iC−WJB
R3
27kΩ
Figure 11: Analogue modulation during CW operation
Analogue modulation during CW operation
ISET while turning on the power supply for the OTA cir-
The modulation cut-off frequency is determined by the cuitry, however, RSET should be connected to the OTA
capacitor CI as well as by the operating point set with output (instead of to GND). The maximum current pos-
the resistor RSET. With CI = 100 nF and RSET = R3 = sible at ISET must be taken into consideration when
15 kΩ the cut-off frequency is approx. 30 kHz, with CI = dimensioning the capacitor CI.
22 nF and the same resitor value of about 150 kHz.
PC board layout
The laser power can also be modulated by adapting a The ground connections of the external components
current source, e.g. by using an operational amplifier CI, CWD and RSET have to be directly connected at
with a current output (OTA). To limit the current at pin the IC with the GND terminal.
DEMO BOARD
For the devices iC-WJ/WJZ/WJB a Demo Board is the schematic diagram and the component side of the
available for test purpose. The following figures show test PCB.
ICHAUS [ IC-HAUS GMBH ]
