SM8122A Datasheet, PDF (1/13 Pages) Nippon Precision Circuits Inc – White LED Driver IC

SM8122A
White LED Driver IC
OVERVIEW
The SM8122A is a high efficiency step-up DC/DC converter. Due to high voltage CMOS process realizing
25V output supply as maximum value, 2 to 6 lights of white LED connected in series can be lighted. By con-
necting in series, current variation among LED is eliminated. Current value sent to white LED can be set by
external resistors. In addition, brightness can also be adjusted by control to FB pin or CE pin. Since the
SM8122A has an over voltage protection circuit built-in, it dispenses with the existing external ZD (zener
diode). Besides, the switching frequency of the SM8122A is higher (2.0MHz) than the existing product
(SM8121A), so that it can respond to lower inductance value.
FEATURES
I Boost-up control using PWM
I 2 to 6 lights of white LED (connected in series)
lighted
I Output current value can be set by external resis-
tors (51Ω: 9.8mA, 33Ω: 15.2mA, 24Ω: 20.8mA)
I Brightness adjustable by control to FB pin or CE
pin
I Current variation among LED decreased by high
precision
I High efficient drive by step-up model
I Over voltage protection circuit built-in
I Supply voltage range: 2.3 to 5.5V
I Maximum output voltage: 25V
I Quiescent current: 820µA (typ)
I Standby current: 1.0µA (max)
I R_ON (Switching MOS-Tr): 2Ω (typ)
I Switching frequency: 2.0MHz (typ)
I Output current detection accuracy: ± 2%
I Package: SOT23-6W (SM8122AH)
MSON-6 (SM8122AD)
APPLICATIONS
I Cellular phone
I Pager
I Digital still camera
I Handy terminal
I PDAs
I Portable games
I White LED drive
I LCD bias supply
I Flash memory supply
PINOUT
(Top view)
I SOT23-6W
SW 1
VOUT 2
FB 3
I MSON-6
VDD 1
SW 2
CE 3
6 VDD
5 VSS
4 CE
6 VOUT
5 VSS
4 FB
ORDERING INFORMATION
Device
SM8122AH
SM8122AD
Package
SOT23-6W
MSON-6
NIPPON PRECISION CIRCUITS INC.—1