LM3642_15 Datasheet, PDF (1/30 Pages) Texas Instruments – Synchronous Boost LED Flash Driver

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LM3642
SNVS891H – SEPTEMBER 2012 – REVISED SEPTEMBER 2015
LM3642 1.5-A Synchronous Boost LED Flash Driver With High-Side Current Source
1 Features
•1 1.5-A High-Side Current Source for Single LED
• > 85% Efficiency in Torch Mode (at 100 mA) and
Flash Mode (at 1 A to 1.5 A)
• Accurate Programmable Flash LED Current from
93 mA to 1.5 A
• Accurate Programmable Torch LED Currents:
– 48.4 mA to 375 mA
– 24 mA to 187 mA (LT option)
• Small Solution Size: < 20 mm²
• Soft-Start Operation for Battery Protection
• Hardware Strobe Enable
• Synchronization Input for RF Power Amplifier
Pulse Events
• V_IN Flash Monitor Optimization
• 400-kHz I²C-Compatible Interface
• 0.5-mm Pitch, 9-Bump DSBGA
2 Applications
Camera Phone LED Flash
3 Description
The LM3642 is a 4-MHz fixed-frequency synchronous
boost converter plus 1.5-A 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 1.5 A. 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 4-MHz switching frequency, overvoltage
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 DSBGA package and operates over the
−40°C to 85°C temperature range.
Device Information⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (MAX)
LM3642
DSBGA (9)
1.69 mm × 1.64 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Simplified Schematic
1 2H
2.5V to 5.5V
10 2F
IN
SW _OUT
10 2F
STROBE
LED
TX/TORCH
SDA
SCL
GND
Flash
LED
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.