Home Power management LED drivers Illumination LED drivers

LM3643

ACTIVE

Dual LED flash driver Capable of up to 1.5A

Product details

Input voltage type DC/DC Topology Boost, current mode Vin (min) (V) 2.5 Vin (max) (V) 5.5 Vout (max) (V) 5.5 Vout (min) (V) 2.5 Iout (max) (A) 1.5 Iq (typ) (mA) 0.3 Features I2C control, IR Mode Operating temperature range (°C) -40 to 85 Dimming method Analog, PWM Number of channels 2 Rating Catalog
Input voltage type DC/DC Topology Boost, current mode Vin (min) (V) 2.5 Vin (max) (V) 5.5 Vout (max) (V) 5.5 Vout (min) (V) 2.5 Iout (max) (A) 1.5 Iq (typ) (mA) 0.3 Features I2C control, IR Mode Operating temperature range (°C) -40 to 85 Dimming method Analog, PWM Number of channels 2 Rating Catalog
DSBGA (YFF) 12 2.52000000000000018 mm² 1.4000000000000001 x 1.8
  • 1.5 A Total Allowed LED Current During Operation
    (ILED1 + ILED2 = 1.5 A)
  • Dual Independent LED Current Source Programmability
  • Accurate and Programmable LED Current Range from
    1.4 mA to 1.5 A
  • Optimized Flash LED Current During Low Battery
    Conditions (IVFM)
  • > 85% Efficiency in Torch Mode (@ 100 mA) and
    Flash Mode (@1 A to 1.5 A)
  • Grounded Cathode LED Operation for Improved Thermal
    Management
  • Small Solution Size: < 16 mm2
  • Hardware Strobe Enable (STROBE)
  • Synchronization Input for RF Power Amplifier Pulse
    Events (TX)
  • Hardware Torch Enable (TORCH/TEMP)
  • Remote NTC Monitoring (TORCH/TEMP)
  • 400-kHz I2C-Compatible Interface
    • LM3643 (I2C Address = 0x63)
    • LM3643A (I2C Address = 0x67)
  • 1.5 A Total Allowed LED Current During Operation
    (ILED1 + ILED2 = 1.5 A)
  • Dual Independent LED Current Source Programmability
  • Accurate and Programmable LED Current Range from
    1.4 mA to 1.5 A
  • Optimized Flash LED Current During Low Battery
    Conditions (IVFM)
  • > 85% Efficiency in Torch Mode (@ 100 mA) and
    Flash Mode (@1 A to 1.5 A)
  • Grounded Cathode LED Operation for Improved Thermal
    Management
  • Small Solution Size: < 16 mm2
  • Hardware Strobe Enable (STROBE)
  • Synchronization Input for RF Power Amplifier Pulse
    Events (TX)
  • Hardware Torch Enable (TORCH/TEMP)
  • Remote NTC Monitoring (TORCH/TEMP)
  • 400-kHz I2C-Compatible Interface
    • LM3643 (I2C Address = 0x63)
    • LM3643A (I2C Address = 0x67)

The LM3643 is a dual LED flash driver that provides a high level of adjustability within a small solution size. The LM3643 utilizes a 2-MHz or 4-MHz fixed-frequency synchronous boost converter to provide power to the dual 1.5-A constant current LED sources. The total LED current the LM3643 boost can deliver is 1.5 A (ILED1 + ILED2 ). The dual 128 level current sources provide the flexibility to adjust the current ratios between LED1 and LED2 with each driver capable of delivering a maximum of 1.5 A (ex: ILED1 = 1.5 A and ILED2 = 0FF, ILED1 = 0FF and ILED2 = 1.5 A, or a current configuration with a current less than 1.5 A , ILED1 = 950 mA and ILED2 = 250 mA). An adaptive regulation method ensures the current sources remain in regulation and maximizes efficiency.

Features of the LM3643 are controlled via an I2C-compatible interface. These features include: hardware flash and hardware torch pins (STROBE and TORCH/TEMP), a TX interrupt, and an NTC thermistor monitor. The device offers independently programmable currents in each output leg to drive the LEDs in a Flash or Movie Mode (Torch) condition.

The 2-MHz or 4-MHz switching frequency options, overvoltage protection (OVP), and adjustable current limit allow for the use of tiny, low-profile inductors and (10-µF) ceramic capacitors. The device operates over a –40°C to 85°C ambient temperature range.

The LM3643 is a dual LED flash driver that provides a high level of adjustability within a small solution size. The LM3643 utilizes a 2-MHz or 4-MHz fixed-frequency synchronous boost converter to provide power to the dual 1.5-A constant current LED sources. The total LED current the LM3643 boost can deliver is 1.5 A (ILED1 + ILED2 ). The dual 128 level current sources provide the flexibility to adjust the current ratios between LED1 and LED2 with each driver capable of delivering a maximum of 1.5 A (ex: ILED1 = 1.5 A and ILED2 = 0FF, ILED1 = 0FF and ILED2 = 1.5 A, or a current configuration with a current less than 1.5 A , ILED1 = 950 mA and ILED2 = 250 mA). An adaptive regulation method ensures the current sources remain in regulation and maximizes efficiency.

Features of the LM3643 are controlled via an I2C-compatible interface. These features include: hardware flash and hardware torch pins (STROBE and TORCH/TEMP), a TX interrupt, and an NTC thermistor monitor. The device offers independently programmable currents in each output leg to drive the LEDs in a Flash or Movie Mode (Torch) condition.

The 2-MHz or 4-MHz switching frequency options, overvoltage protection (OVP), and adjustable current limit allow for the use of tiny, low-profile inductors and (10-µF) ceramic capacitors. The device operates over a –40°C to 85°C ambient temperature range.

Download View video with transcript Video

Technical documentation

star =Top documentation for this product selected by TI
No results found. Please clear your search and try again.
View all 8
Type Title Date
* Data sheet LM3643 Synchronous Boost Dual LED Flash Driver with 1.5-A High-Side Current Sources datasheet (Rev. A) PDF | HTML 17 Nov 2014
Application note No Boost Inductor Design with LM364x for Long-Time Focusing in Camera Module PDF | HTML 16 Feb 2022
White paper Common LED Functions and LED Driver Design Considerations 21 Sep 2020
Application note LED Flash-Protection Features 23 Aug 2017
Application note Using Flash LED Drivers for Infrared (IR) LED Applications 20 Mar 2017
Application note Using the LM3643/4/8 in an Inductorless and/or Simplified PCB Routing Configurat 11 Oct 2016
Technical article Shrink your LED flash solution PDF | HTML 10 Dec 2015
EVM User's guide LM3643EVM User’s Guide 19 Aug 2014

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LM3643EVM — Synchronous Boost Dual LED Flash Driver Evaluation Module W/ 1.5A High-Side Current Sources

The LM3643EVM aids in evaluation of the LM3643 Synchronous Boost Dual LED Flash Driver W/ 1.5A High-Side Current Sources.  The 2/4 MHz synchronous boost provides up to 1.5A of total LED current to the dual independently controllable high side current sources.  Each current source can (...)

User guide: PDF
Not available on TI.com
GUI for evaluation module (EVM)

SNVC174 LM3643EVM GUI

Supported products & hardware

Supported products & hardware

Products
Illumination LED drivers
LM3643 Dual LED flash driver Capable of up to 1.5A
Hardware development
Evaluation board
LM3643EVM Synchronous Boost Dual LED Flash Driver Evaluation Module W/ 1.5A High-Side Current Sources
Simulation model

LM3643 PSpice Transient Model

SNVMA17.ZIP (77 KB) - PSpice Model
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Package Pins CAD symbols, footprints & 3D models
DSBGA (YFF) 12 Ultra Librarian

Ordering & quality

Information included:
  • RoHS
  • REACH
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

Recommended products may have parameters, evaluation modules or reference designs related to this TI product.

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​

Videos