SM8136A
White LED Driver IC
OVERVIEW
The SM8136A is a charge pump type white LED driver. It can drive 1 to 3 backlight white LED connected in
parallel, making it ideal for portable devices with small LCD. The charge pump switches between
×
1 bypass
mode to
×
1.5 boost mode in response to LED drive current requirements. The boost switching occurs in
response to the drive current of all the connected LED and thus supports variations in LED forward-bias volt-
age drop (VF). Besides, the detection of switching is repeated in approx. 1sec-cycle by mode reset action, the
SM8136A can respond to temporary variation of supply voltage. These ingenuities on switching detection can
prolong the battery life to the fullest extent. Each LED drive current is controlled by a 3-channel LED drive
current control circuit.
FEATURES
I
PINOUT
(Top view)
DIN1
DIN2
DIN3
NC
GND
VIN
C1M
C2M
C2P
EN
VOUT
C1P
I
I
I
I
I
I
I
I
I
I
I
2.00
±
0.07
A
B
1.00
0.40
×
2 = 0.80
±
0.05
0.60
I
12
8−C0.08
1
1
12
I
I
I
I
I
I
I
I
I
Cellular phone
PDA
Portable games
Portable audio equipment
Handy terminal
Digital still camera
Digital video camera
LCD panel back light
White LED driving
C0.30
0.60
0.70
±
0.05
0.10 S A B
0.05 max
0.75 max
0.18
±
0.05
φ0.05
M S A B
0.10 S
S
0.05 S
0.40
ORDERING INFORMATION
Device
SM8136AB
Package
12-pin QFN
SEIKO NPC CORPORATION —1
1.00
APPLICATIONS
2.00
±
0.07
0.25
±
0.07
Top view
Bottom view
0.40
×
2 = 0.80
±
0.05
Battery life extension by automatic charge pump
switch between
×
1 to
×
1.5 according to the detec-
tion of the LED drive current
Controlling 1 to 3 lights of white LED connected
in parallel
1-wire input controlling
ON/OFF and brightness control by signal control-
ling of EN pin
Soft start circuit built-in
Input voltage range
No-load current (I
OUT
= 0mA): 2.7 to 4.6V
Load current (I
OUT
= 60mA): 3.0 to 4.6V
Maximum output voltage: 5.0V (typ)
Maximum output current: 60mA (typ)
Quiescent current
Not-switching (
×
1 mode): 0.3mA (typ)
Switching (
×
1.5 mode): 1.0mA (typ)
Standby current: 0.01
µ
A (typ)
Operating frequency (boost mode): 1.0MHz (typ)
LED drive current accuracy between channel:
± 5.0%
Package: 12-pin QFN
PACKAGE DIMENSIONS
(Unit: mm)
NPC [ NIPPON PRECISION CIRCUITS INC ]
