SC628A Datasheet, PDF (1/21 Pages) Semtech Corporation – LED Flash Driver Charge Pump with 1000mA Flash Mode, 275mA Spotlight Mode, 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 — 1000mA max in flash mode, 275mA max
continuous for spotlight
„ Charge pump frequency — 250kHz
„ I²C compatible interface — up to 400kHz
„ External flash control pin to sync with camera
„ One second flash time out with disable feature
„ 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
SC628A
LED Flash Driver
Charge Pump with 1000mA Flash Mode,
275mA Spotlight Mode, and I²C Interface
Description
The SC628A is a high efficiency charge pump LED driver
using Semtech’s proprietary charge pump technology.
Performance is optimized for use in single-cell Li-ion
battery applications. The load and supply conditions
determine whether the charge pump operates in 1x, 1.5x,
or 2x mode.
The charge pump provides continuous spotlight mode
current or pulsed flash mode current to an LED using a
dedicated current sink. In flash mode, a flash-timeout
feature turns off the flash if active for longer than 1 second.
In spotlight mode, the timeout feature is disabled to allow
continuous operation of the LED.
The SC628A uses an I²C compatible serial interface to set
the flash mode or the spotlight mode current. The flash/
spotlight output is triggered via either the I²C interface or
a dedicated flash enable pin (FLEN).
In sleep mode, the device reduces quiescent current to
100μA while continuing to monitor the serial interface.
Total current reduces to 0.1μA in shutdown.
Typical Application Circuit
V_BAT = 3.0V to 5.5V
C_IN
4.7μF
I²C Data
I²C Clock
Flash Control
Enable Control
July 14, 2009
IN
OUT
SDA ^SC628A
SCL
FLEN
EN
FL
AGND
PGND
C1+ C1- C2+ C2-
C_OUT
4.7μF
FLASH
C1
2.2μF
C2
2.2μF
US Patents: 6,504,422; 6,794,926
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