SC622A Datasheet, PDF (1/23 Pages) Semtech Corporation – LED Light Management Unit Charge Pump, 400mA Flash LED, Dual LDOs, and I2C Interface

POWER MANAGEMENT
Features
„ Input supply voltage range — 3.0V to 5.5V
„ Charge pump modes — 1x, 1.5x and 2x
„ Flash LED — 400mA max in flash mode, 250mA max
continuous for spotlight
„ Two user-configurable 100mA low-noise LDO
regulators
„ Charge pump frequency — 250kHz
„ I²C compatible interface — up to 400kHz
„ External flash control pin to sync with camera
„ Optional 1s flash time out
„ Automatic sleep mode (flash off ) — I = 100μA
Q
„ Low shutdown current — 0.1μA (typical)
„ Ultra-thin package — 3mm x 3mm x 0.6mm
„ Fully WEEE and RoHS compliant
Applications
„ Cellular phone flash
„ PDA flash
„ Camera I/O and core power
SC622A
LED Light Management Unit
Charge Pump, 400mA Flash LED, Dual
LDOs, and I²C Interface
Description
The SC622A is a high efficiency charge pump LED driver
using Semtech’s proprietary mAhXLife^TM technology.
Performance is optimized for use in single-cell Li-ion
battery applications.
The charge pump provides continuous or bursted current
to a flash LED using a dedicated flash driver current sink.
The load and supply conditions determine whether the
charge pump operates in 1x, 1.5x, or 2x mode. A flash-
timeout feature disables the flash if active for longer than
1 second. The SC622A also provides two low-dropout,
low-noise linear regulators for powering a camera module
or other peripheral circuits.
The SC622A uses an I²C compatible serial interface. The
interface controls all functions of the device, including
flash current and two LDO voltage outputs. The flash/
spotlight output is triggered via either the I²C interface or
a dedicated pin.
In sleep mode, the device reduces quiescent current to
100μA while continuing to monitor the serial interface.
The two LDOs can be enabled when the device is in sleep
mode. Total current reduces to 0.1μA in shutdown.
Typical Application Circuit
V_BAT
C_IN
2.2μF
I²C Data
I²C Clock
Flash Control
Enable Control
C_BYP
22nF
July 19, 2007
VIN
VOUT
SDA ^SC622A
SCL
FLEN
EN
C_OUT
4.7μF
FLASH
BYP
AGND
PGND
FL
LDO 1
LDO 2
C1+ C1- C2+ C2-
C1
2.2μF
C2
2.2μF
C_LDO1
1μF
© 2007 Semtech Corporation
V_LDO1 = 2.5V to 3.3V
V_LDO2 = 1.5V to 1.8V
C_LDO2
1μF
US Patents: 6,504,422; 6,794,926
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