BCR401R
Aug-29-2001
1
LED Driver
Supplies stable bias current even at low battery
voltage
Low voltage drop of 0.75V
Ideal for stabilizing bias current of LEDs
Negative temperature coefficient protects
LEDs against thermal overload
EHA07188
4
3
2
1
Type
Marking
Pin Configuration
Package
BCR401R
W5s
1 = GND
2 = I
out
3 = V
S
4 = R
ext
SOT143R
Maximum Ratings
Parameter
Symbol
Value
Unit
Source voltage
V
S
18
V
Output current
I
out
60
mA
Output voltage
V
out
16
V
Reverse voltage between all terminals
V
R
0.5
Total power dissipation
, T
S
= 87 C
P
tot
330
mW
Junction temperature
T
j
150
C
Storage temperature
T
stg
-65 ... 150
Thermal Resistance
Parameter
Symbol
Value
Unit
Junction - soldering point
1)
R
thJS
190
K/W
1For calculation of R
thJA
please refer to Application Note Thermal Resistance
BCR401R
Aug-29-2001
2
Electrical Characteristics at T
A
=25C, unless otherwise specified
Parameter
Symbol
Values
Unit
min.
typ.
max.
Characteristics
Supply current
V
S
= 10 V
I
S
350
440
540
A
Output current
V
S
= 10 V, V
out
= 7.6 V
I
out
9
10
11
mA
DC Characteristics with stabilized LED load
Lowest sufficient battery voltage overhead
I
out
> 8mA
V
Smin
-
1.2
-
V
Voltage drop (V
S
- V
CE
)
I
out
= 20 mA
V
drop
-
0.75
-
Output current change versus T
A
V
S
= 10 V
I
out
/I
out
-
-0.3
-
%/K
Output current change versus V
S
V
S
= 10 V
I
out
/I
out
-
2
-
%/V
BCR401R
Aug-29-2001
3
Output current versus supply voltage
I
out
= f (V
S
); R
ext
= Parameter
Load: two LEDs with V
F
= 3.8V in series
0
2
4
6
8
10
12
14
16
V
20
V
S
-3
10
-2
10
-1
10
A
I
out
Rext = 36 Ohm
Rext = 82 Ohm
Rext = 160 Ohm
Rext = open
Total power dissipation
P
tot
= f(T
S
)
0
20
40
60
80
100
120 C
150
T
S
0
100
200
300
mW
500
P
tot
Supply current versus supply voltage
I
S
= f(V
S
)
Load: two LEDs with V
F
= 3.8V in series
0
2
4
6
8
10
12
14
16
V
20
V
S
-5
10
-4
10
-3
10
A
I
S
Application Circuit:
V d r o p
B C R 4 0 1 R
R e x t
3
4
2
1
+ V s
I s
I o u t
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