GUI for evaluation module (EVM)
Data sheet
LM3644
- Dual Independent 1.5-A LED Current Source Programmability
- Accurate and Programmable LED Current Range from 1.4 mA to 1.5 A
- Torch Currents up to 360 mA (LM3644TT)
- Flash Timeout Values up to 1.6 seconds (LM3644TT)
- Optimized Flash LED Current During Low Battery Conditions (IVFM)
- > 85% Efficiency in Torch Mode (at 100 mA) and Flash Mode (at 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
- LM3644 (I2C Address = 0x63)
The LM3644 is a dual LED flash driver that provides a high level of adjustability within a small solution size. The LM3644 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 dual 128 level current sources provide the flexibility to adjust the current ratios between LED1 and LED2. An adaptive regulation method ensures the current sources remain in regulation and maximizes efficiency.
Features of the LM3644 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.
For all available packages, see the orderable addendum at the end of the data sheet.Technical documentation
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View all 8 | Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | LM3644 Dual 1.5-A Current Source Camera Flash LED Driver datasheet (Rev. E) | PDF | HTML | 08 Sep 2016 |
| 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 | |
| User guide | LM3644 User Guide | 28 May 2014 |
Design & development
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Evaluation board
LM3644EVM — Synchronous Boost Dual LED Flash Driver Evaluation Module W/ 1.5A High-Side Current Sources
The LM3644EVM 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 power to the dual independently controllable high side current sources. Each current source can provide a current up to 1.5A (...)
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 |
Ordering & quality
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