iC-WJ, iC-WJZ
LASER DIODE DRIVER
Rev C1, Page 1/12
FEATURES
o
Laser diode driver for continuous and pulsed operation (CW to
300 kHz) up to 250 mA
o
Averaging control of laser power
o
Simple adjustment of the laser power via external resistor
o
Adjustable watchdog at the switching input to protect the laser
diode
o
Soft-start after power-on
o
Driver shutdown with overtemperature and undervoltage
o
Single 5 V supply
o
Simple circuitry
o
iC-WJ
for laser diodes with 50 to 500 µA monitor current
o
iC-WJZ
for laser diodes with 0.15 to 1.5 mA monitor current
APPLICATIONS
o
General purpose laser diode
driver
PACKAGES
SO8
MSOP8
BLOCK DIAGRAM
3
REF
REFERENCE
DRIVER STAGE
1
VCC
5
+5 V
100
µF
C1
C3
ISET
4
INPUT
IN
VCC
REF
AMD
74HCxx
THERMAL
SHUTDOWN
KLD
8
2 nF
LD MD
R1
12Ω
RSET
10 kΩ
6
POWER DOWN
7
2
4
WATCHDOG
1:1 iC−WJ
1:3 iC−WJZ
iC−WJ/WJZ
CWD
2
CWD
CI
3
CI
100 nF..470 nF
usable LD models
GND
1
Copyright © 2006 iC-Haus
http://www.ichaus.com
iC-WJ, iC-WJZ
LASER DIODE DRIVER
Rev C1, Page 2/12
DESCRIPTION
The iC-WJ and iC-WJZ devices are driver ICs for
laser diodes in continuous and pulsed operation up
to 300 kHz. The laser diode is activated via switching
input IN. A control to the mean value of the optical
laser power and integrated protective functions en-
sure nondestructive operation of the sensitive semi-
conductor laser.
The IC contains protective diodes to prevent destruc-
tion due to ESD, a protective circuit to guard against
overtemperature and undervoltage and a soft-start
for the laser diode driver to protect the laser diode
when switching on the supply voltage.
An external resistor at ISET is utilised to adapt the
power control to the laser diode being used. The ca-
pacitor at CI determines the recovery time constants
and the start-up time.
A watchdog circuit monitors the switching input IN.
If IN remains low longer than preset by the capac-
itor at CWD, the capacitor of the power control is
discharged at pin CI. This ensures that the current
through the laser diode during the next high pulse at
input IN is not impermissibly high.
PACKAGES
SO8, MSOP8 to JEDEC Standard
PIN CONFIGURATION SO8
(top view)
1
8
PIN FUNCTIONS
No. Name Function
KLD
GND
2
7
CWD
AMD
3
6
CI
4
IN
5
ISET
VCC
1
2
3
4
5
6
7
8
GND
CWD
CI
ISET
VCC
IN
AMD
KLD
Ground
Capacitor for Watchdog
Capacitor for Power Control
Attachment for RSET
5 V Supply Voltage
Input
Anode Monitor Diode
Cathode Laser Diode
PIN CONFIGURATION MSOP8
(top view)
1
GND
CWD
CI
ISET
KLD
AMD
IN
VCC
Code...
...yymm
WJ
iC−WJ
Code
iC-WJ, iC-WJZ
LASER DIODE DRIVER
Rev C1, Page 3/12
ABSOLUTE MAXIMUM RATINGS
Beyond these values damage may occur; device operation is not guaranteed.
Item
No.
Symbol
Parameter
Supply Voltage
Current in CI
Voltage at KLD
Current in KLD
Current in AMD
Current in IN
Current in ISET
Current in CWD
ESD Susceptibility at CWD, CI, ISET,
IN, AMD, KLD
Junction Temperature
Storage Temperature
IN = lo
MIL-STD-883, HBM 100 pF discharged
through 1.5 kΩ
-40
-40
IN = lo
IN = hi
iC-WJ
iC-WJZ
Conditions
Fig.
Min.
0
-4
0
-4
-4
-6
-10
-2
-2
Max.
6
4
6
600
4
6
2
2
2
1.5
150
150
V
mA
V
mA
mA
mA
mA
mA
mA
kV
°C
°C
Unit
G001 VCC
G002 I(CI)
G003 V(KLD)
G004 I(KLD)
G005 I(AMD)
G006 I(IN)
G007 I(ISET)
G008 I(CWD)
G009 Vd()
G010 Tj
G011 Ts
THERMAL DATA
Operating Conditions: VCC = 5 V ±10 %
Item
No.
T01
Symbol
Ta
Parameter
Operating Ambient Temperature Range
(extended temperature range on
request)
Thermal Resistance Chip to Ambient
surface mounted on PCB, without
special cooling
Conditions
Fig.
Min.
-25
Typ.
Max.
90
°C
Unit
T02
Rthja
140
K/W
All voltages are referenced to ground unless otherwise stated.
All currents into the device pins are positive; all currents out of the device pins are negative.
iC-WJ, iC-WJZ
LASER DIODE DRIVER
Rev C1, Page 4/12
ELECTRICAL CHARACTERISTICS
Operating Conditions: VCC = 5 V ±10 %, RSET = 2.7...27 kΩ,
iC-WJ:
I(AMD) = 50...500 µA,
iC-WJZ:
I(AMD) = 0.15...1.5 mA, Tj = -25...125 °C, unless otherwise noted.
Item
No.
001
002
003
004
005
Driver
101
102
103
Vs(KLD)
I0(KLD)
I(KLD)
Saturation Voltage at KLD
Leakage Current in KLD
Current in KLD
IN = hi, I(KLD) = 200 mA
IN = lo, V(KLD) = VCC
IN = hi, I(AMD) = 0
-25
27
70
125
225
250
250
250
0.5
0.4
250
1.3
10
V
µA
mA
mA
mA
mA
1.5
1.5
100
100
V
V
ns
ns
Symbol
Parameter
Conditions
Tj
°C
Fig.
Min.
4.5
Typ.
Max.
5.5
15
135
-1.5
0.3
-0.3
1.5
V
mA
ns
V
V
Unit
Total Device
VCC
Iav(VCC)
Permissible Supply Voltage
Range
Supply Current in VCC (average Iav(KLD) = 100 mA,
value)
f(IN) = 200 kHz ±20 %
IN(hi
↔
lo), V(50 %) : I(50 %)
I() = -2 mA, other pins open
Vc()hi = V()
−
VCC; I() = 2 mA,
other pins open
tp(IN-KLD) Delay Time Pulse Edge V(IN) to
I(KLD)
Vc()lo
Vc()hi
Clamp Voltage lo at VCC, IN,
AMD, KLD, CI, CWD, ISET
Clamp Voltage hi at IN, AMD,
KLD, GND, CI, CWD, ISET
104
105
106
107
V(AMD)
tr
tf
CR1()
Voltage at AMD
Current Rise Time in KLD
Current Fall Time in KLD
Current Ratio I(AMD) / I(ISET)
iC-WJ:
I(AMD) = 500 µA
iC-WJZ:
I(AMD) = 1.5 mA
Imax(KLD) = 20...250 mA,
Ip(): 10
→
90 %
Imax(KLD) = 20...250 mA,
Ip(): 90 %
→
10 %
I(CI) = 0, closed control loop;
iC-WJ
iC-WJZ
V(CI) = 1...3.5 V, ISET open;
iC-WJ
iC-WJZ
0.8
2.4
0.9
2.7
1.60
-25
27
70
125
1
3
1
3
1.2
3.6
1.1
3.3
2.40
V
V
V
V
V
V
V
V
V
V
mV
mV
mV
mV
mV
kΩ
V
V
V
V
V
V
V
108
CR2()
Current Ratio I(AMD) / I(CI)
Input IN
201 Vt()hi
Threshold hi
1.84
1.87
1.88
1.91
1.50
2.20
1.76
1.78
1.79
1.81
10
190
80
90
90
100
4
16
0.1
3.2
2.8
2.3
1.8
1.28
1.22
0.9
1
1.1
202
Vt()lo
Threshold lo
-25
27
70
125
203
Vt()hys
Hysteresis
-25
27
70
125
204
205
206
Rin
V0()
Vtwd()
Pull-Down Resistor
Open-loop Voltage
Threshold for Watchdog
V(IN) = -0.3...VCC + 0.3 V
I(IN) = 0
-25
27
70
125
2.4
2.0
1.5
1.0
1.17
Reference und Thermal Shutdown
301 V(ISET)
Voltage at ISET
27
302
CR()
Current Ratio I(CI) / I(ISET)
V(CI) = 1...3.5 V, I(AMD) = 0
iC-WJ, iC-WJZ
LASER DIODE DRIVER
Rev C1, Page 5/12
ELECTRICAL CHARACTERISTICS
Operating Conditions: VCC = 5 V ±10 %, RSET = 2.7...27 kΩ,
iC-WJ:
I(AMD) = 50...500 µA,
iC-WJZ:
I(AMD) = 0.15...1.5 mA, Tj = -25...125 °C, unless otherwise noted.
Item
No.
303
304
305
Symbol
RSET
Toff
Thys
Parameter
Permissible Resistor at ISET
(Control Set-up Range)
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
Conditions
Tj
°C
Fig.
Min.
2.7
125
10
3.5
27
402
403
404
405
406
407
408
(*)
Unit
Typ.
Max.
50
150
40
4.3
3.8
3.2
3.8
450
400
1.6
1.5
-15
10
0.19
0.38
-3
45
0.57
300
kΩ
°C
°C
V
V
V
mV
mV
V
V
µA
µs
µs/pF
Power-Down and Watchdog
401 VCCon
Turn-on Threshold VCC
VCCoff
VCChys
Vs(CI)off
Vs(CI)wd
Ipu(CWD)
tpmin
Kwd
(*)
Undervoltage Threshold at VCC
Hysteresis
Saturation Voltage at CI with
undervoltage
Saturation Voltage at CI with
IN = lo
Pull-Up Current at CWD
Min. Activation Time for
Watchdog
Constant for Calculating the
Watchdog Activation Time
VCChys = VCCon
−
VCCoff
27
I(CI) = 300 µA, VCC < VCCoff
I(CI) = 300 µA, t(IN = lo) > tp
(*)
V(CWD) = 0, IN = lo
IN = lo, CWD open
IN = lo
tp = (C(CWD)
∗
Kwd) + tpmin
(see Applications Information)
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