iC-WJB
2.7V LASER DIODE DRIVER
Rev C1, Page 1/12
SO8
FEATURES
APPLICATIONS
LD driver for continuous or pulsed operation (CW to 300kHz)
of up to 100mA
Average control of laser power
Simple LD power adjustment via external resistor
Adjustable watchdog supervises digital input signals
Soft starting after power-on
Driver shutdown in the case of overtemperature and
undervoltage
Operation at 2.7V..6V suits battery-powered systems with
two to four AA/AAA cells
Reverse battery protection
Battery-powered LD modules
LD Pointers
PACKAGES
BLOCK DIAGRAM
2000
iC-Haus GmbH
Tel +49-6135-9292-0
Integrated Circuits
Fax +49-6135-9292-192
Am Kuemmerling 18, D-55294 Bodenheim
http://www.ichaus.com
( VCC > 4.5V )
iC-WJB
REF
VCC
REFERENCE
WATCHDOG
THERMAL
POWER DOWN
INPUT
DRIVER STAGE
REF
3
CI
CWD
AMD
ISET
GND
CWD
IN
CI
KLD
VCC
2.7..6V
MD
LD
47F
C1
2
R2
Z6V8
D1
4
6
2
3
1
1
7
8
5
SHUTDOWN
VB
MD
LD
R1
2nF
C3
0..2
RSET
2.7..330k
470nF
(..pF)
alternative LD model
iC-WJB
2.7V LASER DIODE DRIVER
Rev C1, Page 2/12
KLD
AMD
IN
VCC
GND
CWD
CI
ISET
4
3
2
1
5
6
7
8
DESCRIPTION
The iC-WJB device is a driver IC for laser diodes in continuous or pulsed operation of up to 300kHz. The
broad power supply range of 2.7V to 6V and the integrated reverse battery protection allows for battery-
operation with two to four AA/AAA cells.
The laser diode is activated via switching input IN. A control to the mean value of the optical laser power
(APC) and integrated protective functions ensure nondestructive operation of the sensitive semiconductor
laser.
The IC contains protective diodes to prevent destruction due to ESD, a protective circuit to guard against
overtemperature and undervoltage and a soft-start circuit to protect the laser diode when switching on the
power supply.
Short-term reversed battery connection destroy neither the IC nor the laser diode.
An external resistor at ISET is employed to adapt the APC to the laser diode being used. The capacitor at CI
determines the recovery time constants and the starting time.
A watchdog circuit monitors the switching input IN. If IN remains low longer than preset by the capacitor at
CWD, the capacitor of the APC 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 to JEDEC Standard
PIN CONFIGURATION SO8
PIN FUNCTIONS
(top view)
No. Name Function
1
GND
Ground
2
CWD
Capacitor for Watchdog
3
CI
Capacitor for Power Control
4
ISET
Attachment for RSET
5
VCC
+2.7V to +6V Supply Voltage
6
IN
Input
7
AMD
Monitor Diode Anode
8
KLD
Laser Diode Cathode
iC-WJB
2.7V LASER DIODE DRIVER
Rev C1, Page 3/12
All voltages are referenced to ground unless otherwise noted.
All currents into the device pins are positive; all currents out of the device pins are negative.
ABSOLUTE MAXIMUM RATINGS
Values beyond which damage may occur; device operation is not guaranteed.
Item
Symbol
Parameter
Conditions
Fig.
Unit
Min.
Max.
G001 VCC
Supply Voltage VCC
-0.3
6
V
G002 VCC
Reverse Voltage at VCC
T< 10sec
-4
V
G003 I(VCC)
Current in VCC
T< 10sec
-500
50
mA
G101 I(CI)
Current in CI
-4
4
mA
G102 V(KLD)
Voltage at KLD
IN= lo
0
9
V
G103 I(KLD)
Current in KLD
IN= hi
IN= lo
-4
-4
400
4
mA
mA
G104 I(AMD)
Current in AMD
-6
6
mA
G201 I(IN)
Current in IN
-10
2
mA
G301 I(ISET)
Current in ISET
-2
2
mA
G401 I(CWD)
Current in CWD
IN= lo
-2
2
mA
EG1 Vd()
ESD Susceptibility at
CWD, CI, ISET, IN, AMD, KLD
MIL-STD-883, HBM 100pF
discharged through 1.5k
S
1
kV
TG1 Tj
Junction Temperature
-40
150
C
TG2 Ts
Storage Temperature
-40
150
C
THERMAL DATA
Operating Conditions: VCC= 2.7..6V
Item
Symbol
Parameter
Conditions
Fig.
Unit
Min.
Typ.
Max.
T1
Ta
Operating Ambient Temperature
Range
(extended range on request)
-25
90
C
T2
Rthja
Thermal Resistance Chip / Ambient
soldered on PCB, no additional
cooling areas
140
K/W
iC-WJB
2.7V LASER DIODE DRIVER
Rev C1, Page 4/12
ELECTRICAL CHARACTERISTICS
Operating Conditions:
VCC= 2.7..6V, RSET= 2.7..27k
S
, I(AMD)= 0.15..1.5mA, Tj= -25..125C, unless otherwise noted.
Item
Symbol
Parameter
Conditions
Tj
Fig.
Unit
E
C
Min.
Typ.
Max.
Total Device
001
VCC
Permissible Supply Voltage
2.7
6
V
002
Idc(VCC) Supply Current in VCC
RSET= 5k
S
, IN= hi,
Idc(KLD)= 40mA
4
7
13
mA
003
I0(VCC)
Standby Supply Current in VCC
RSET= 5k
S
, IN= lo
27
5
mA
004
Iav(VCC) Supply Current in VCC
(average value)
Ipk(KLD)= 80mA,
f(IN)= 200kHz 20%, twhi/twlo= 1
9
15
mA
005
tp(IN-
KLD
Delay Time Pulse Edge V(IN) to
I(KLD)
IN(hi
76
lo),
V(50%):I(50%)
65
135
ns
006
Pcon
Power Consumption
VCC= 3V, V(KLD)
.
0.6V,
RSET= 5k
S
, Idc(KLD)= 40mA
50
mW
E001 Vc()hi
Clamp Voltage hi at
VCC,IN,AMD,KLD,CI,CWD, ISET
I()= 2mA, other pins open
27
6.2
7.5
9
V
V
Driver Stage
101
Vs(KLD)
Saturation Voltage at KLD
IN= hi, I(KLD)= 80mA
27
0.11
0.3
V
V
102
Vs(KLD)
Saturation Voltage at KLD
IN= hi, I(KLD)= 100mA
0.4
V
103
I0(KLD)
Leakage Current in KLD
IN= lo, V(KLD)= VCC
10
A
104
V(AMD)
Voltage at AMD
I(AMD)= 1.5mA
27
0.4
0.84
1.0
V
V
105
tr
Current Rise Time in KLD
Imax(KLD)= 20..80mA,
Ip(): 10% to 90%
27
30
100
ns
ns
106
tf
Current Fall Time in KLD
Imax(KLD)= 20..80mA,
Ip(): 90% to 10%
27
20
100
ns
ns
107
K/KL
Control Tolerance
K= I(AMD) RSET
KL constant for each lot,
VCC steady
0.85
1
1.15
108
CR1()
Current Ratio I(AMD) / I(ISET)
I(CI)= 0, closed control
RSET= 2.7..27k
S
RSET= 27..330k
S
2.4
2.4
3
3.6
3.8
5.4
109
CR2()
Current Ratio I(AMD) / I(CI)
V(CI)= 1..2V, ISET open
2.7
3
3.3
110
TC1()
Temperature Coefficient of
Current Ratio I(AMD) / I(ISET)
I(CI)= 0, closed control
RSET= 2.7..27k
S
RSET= 27..330k
S
0.01
-0.1
-0.25
%/C
%/C
Input IN
201
Vt()hi
Threshold hi
45
70
%VCC
202
Vt()lo
Threshold lo
40
65
%VCC
203
Vt()hys
Hysteresis
27
20
65
mV
mV
204
Rin
Pull-Down Resistor
V(IN)= -0.3..VCC
27
4
10
16
k
S
k
S
205
V0()
Open-loop Voltage
I(IN)= 0
0.1
V
iC-WJB
2.7V LASER DIODE DRIVER
Rev C1, Page 5/12
ELECTRICAL CHARACTERISTICS
Operating Conditions:
VCC= 2.7..6V, RSET= 2.7..27k
S
, I(AMD)= 0.15..1.5mA, Tj= -25..125C, unless otherwise noted.
Item
Symbol
Parameter
Conditions
Tj
Fig.
Unit
E
C
Min.
Typ.
Max.
Reference und Thermal Shutdown
301
V(ISET)
Voltage at ISET
27
1.19
1.22
1.27
V
V
302
CR()
Current Ratio I(CI) / I(ISET)
V(CI)= 1..2V, I(AMD)= 0
0.9
1
1.12
303
RSET
Permissible Resistor at ISET
(Control Setup Range)
2.7
330
k
S
304
Toff
Thermal Shutdown Threshold
125
150
C
305
Thys
Thermal Shutdown Hysteresis
10
40
C
Power-Down and Watchdog
401
VCCon
Turn-on Threshold VCC
27
2.4
2.6
2.7
V
V
402
VCCoff
Undervoltage Threshold at VCC
27
2.3
2.5
2.6
V
V
403
VCChys
Hysteresis
VCChys= VCCon-VCCoff
70
100
150
mV
404
Vs(CI)off Saturation Voltage at CI in case
of Undervoltage
I(CI)= 300A,
VCC < VCCoff
1.5
V
405
Vs(CI)wd Saturation Voltage at CI for
IN= lo
I(CI)= 300A,
t(IN= lo) > tp (*)
1.5
V
406
Isc(CWD) Pull-Up Current at CWD
V(CWD)= 0, IN= lo
2
15
A
407
tpmin
Min. Activation Time for
Watchdog
IN= lo, CWD open
27
10
25
45
s
s
408
Kwd (*)
Constant for Calculating the
Watchdog Activation Time
IN= lo
27
0.19
0.25
0.57
s/pF
s/pF
(*): tp = ( C(CWD) Kwd ) + tpmin (see Applications Information)
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