ic-wj iC-Haus, ic-wj Datasheet - Page 6

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ic-wj

Manufacturer Part Number
ic-wj
Description
Laser Diode Driver
Manufacturer
iC-Haus
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
IC-WJ
Manufacturer:
ROHM
Quantity:
11 500
Laser Power Adjustment
The iC-WJ and iC-WJZ devices can be adapted to CW
laser diodes from approximately 2 to 40 mW. N- and
M-type models can be used.
To calculate the current required at ISET, the average
optical laser power is to determine:
with peak value P
t
whi
APPLICATIONS INFORMATION
iC-WJ, iC-WJZ
LASER DIODE DRIVER
74HCxx
T .
RSET
4
6
ISET
IN
P
av
peak
INPUT
= P
REFERENCE
Figure 1: Operation of a laser diode according to the example
2
twhi
peak
Figure 2: Duty cycle
and pulse/period duration
CWD
2
t
whi
T
REF
twlo
T
VCC
3
REF
POWER DOWN
WATCHDOG
THERMAL
SHUTDOWN
4
The pin ISET is used for the adjustment to the sensi-
tivity of the monitor diode and to set the desired optical
laser power. The setpoint for the averaging control of
the monitor diode current is preset at this pin.
Example iC-WJ
Laser diode with 5 mW maximum optical output, mon-
itor diode with 0.13 mA/mW, pulse duty factor set to
20 % with P
The resulting average optical power is 1 mW and the
average monitor diode current is 0.13 mA. The resistor
RSET is calculated as:
with the Electrical Characteristics No. 301 for V(ISET)
and No. 108 for current ratio CR1.
Example iC-WJZ
Laser diode with 5 mW maximum optical output, mon-
itor diode with 0.75 mA at 3 mW, CW operation (pulse
duty factor 100 %) with P
470 nF
CI
CI
RSET =
3
iC−WJ/WJZ
DRIVER
1:3 iC−WJZ
peak
1:1 iC−WJ
CR1 V (ISET )
GND
1
I
= 5 mW:
av
1
(AMD)
VCC
KLD
AMD
cw
5
8
7
= 1 mW:
2 nF
=
C3
R1
12 Ω
1 1.22 V
0.13 mA
Rev C1, Page 6/12
+5 V
= 9.4 k
LD
100 uF
C1
MD

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