LM3642 Datasheet, PDF (1/26 Pages) Texas Instruments – LM3642 1.5A Synchronous Boost LED Flash Driver with High-Side Current Source

LM3642
www.ti.com
SNVS891F – SEPTEMBER 2012 – REVISED JANUARY 2014
LM3642 1.5A Synchronous Boost LED Flash Driver with High-Side Current Source
Check for Samples: LM3642
FEATURES
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•2 1.5A High-Side Current Source for Single LED
• > 85% Efficiency in Torch Mode (@ 100 mA)
and Flash Mode (@1A to 1.5A)
• Accurate Programmable Flash LED Current
from 93 mA to 1.5A
• Accurate Programmable Torch LED Currents
from 48.4 mA to 375 mA and 24 mA to 187 mA
(LM3642LT)
• Small Solution Size: < 20 mm²
• Soft-Start Operation for Battery Protection
• Hardware Strobe Enable
• Synchronization Input for RF Power Amplifier
Pulse Events
• VIN Flash Monitor Optimization
• 400 kHz I²C-Compatible Interface
• 0.5 mm Pitch, 9-Bump DSBGA
APPLICATIONS
• Camera Phone LED Flash
DESCRIPTION
The LM3642 is a 4MHz fixed-frequency synchronous
boost converter plus 1.5A constant current driver for
a high-current white LED. The high-side current
source allows for grounded cathode LED operation
providing Flash current up to 1.5A. An adaptive
regulation method ensures the current source
remains in regulation and maximizes efficiency.
The LM3642 is controlled via an I²C-compatible
interface. Features include a hardware flash enable
(STROBE) allowing a logic input to trigger the flash
pulse as well as a TX input which forces the flash
pulse into a low-current Torch Mode, allowing for
synchronization to RF power amplifier events or other
high-current conditions.
The 4MHz switching frequency, over-voltage
protection and adjustable current limit settings allow
the use of tiny, low-profile inductors and (10 µF)
ceramic capacitors. The device is available in a small
9-bump (1.615 mm x 1.665 mm x 0.6 mm) DSBGA
package and operates over the −40°C to +85°C
temperature range.
Typical Application Circuit
1 2H
2.5V to 5.5V
10 2F
IN
SW _OUT
10 2F
STROBE
LED
TX/TORCH
SDA
SCL
GND
Flash
LED
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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