GUI for evaluation module (EVM)
Data sheet
LM3643
- 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.
Technical documentation
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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
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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
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 |
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