LM3561
Synchronous boost converter with 600mA high side LED driver and I2C-compatible interface
LM3561
- High-Side Current Source Allows Grounded LED Cathode
- Up to 90% Efficient
- Ultra-Small Solution Size: <16mm2
- Three Operating Modes: Torch, Flash, and LED Indicator
- Accurate and Programmable LED Current from 18mA to 600mA
- Hardware Flash and Torch Enable
- LED Thermal Sensing and Current Scaleback
- Software Selectable Input Voltage Monitor
- Programmable Flash Timeout
- Dual Synchronization Inputs for RF Power Amplifier Pulse Events
- Open and Short LED Detection
- Active High Hardware Enable for Protection Against System Faults
- 400kHz I2C-compatible Interface
- 12-Bump (1.215mm × 1.615mm × 0.6mm) DSBGA Package
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The LM3561 is a 2-MHz fixed-frequency current-mode synchronous boost converter. The device is designed to operate as a single 600-mA constant current driver for high-current white LEDs. The high-side current source allows for grounded cathode LED operation while the 250-mV regulated headroom voltage ensures that the LED current is well regulated and efficiency remains high.
The main features of the LM3561 include: an I2C-compatible interface for controlling the LED current, a hardware Flash enable input for direct triggering of the Flash pulse, dual TX inputs (TX1 and TX2) which force the Flash pulse into a low-current Torch mode during high battery current instances, an active high hardware enable (HWEN) allowing for fast hardware shutdown during system software failures, a dual mode pin which serves as either an indicator LED driver at up to 18mA or as a dedicated comparator input with an internal 1V reference, designed to monitor the voltage across a negative temperature coefficient thermistor (NTC), and a programmable input voltage monitor which monitors IN and can reduce the flash current or shutdown the device during low battery conditions.
Seven fault flags are available for read back over the I2C-compatible bus. These include: a flash timeout flag indicating the flash pulse has reached the end of the programmable timeout duration, a thermal shutdown flag indicating the LM3561's die temperature has exceeded 150°C, an LED fault flag indicating the output voltage has tripped the over-voltage threshold, or the LED has become shorted, TX1 and TX2 interrupt flags indicating if either of the TX inputs have been triggered, an NTC flag indicating the LED has experienced an over temperature condition, and a VIN Monitor flag indicating the input voltage has fallen below the VIN Monitor threshold.
The LM3561 is available in a tiny (1.215mm × 1.615mm × 0.6mm) 12-bump DSBGA and operates over the temperature range -40°C to +85°C.
Technical documentation
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | Sync Boost Converter w/600mA High Side LED Driver & I2C-Compatible Interface datasheet (Rev. C) | 02 May 2013 | |
| White paper | Common LED Functions and LED Driver Design Considerations | 21 Sep 2020 | ||
| Selection guide | Power Management Guide 2018 (Rev. R) | 25 Jun 2018 | ||
| User guide | AN-2252 LM3561 Evaluation Kit | 08 May 2013 |
Design & development
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PSPICE-FOR-TI — PSpice® for TI design and simulation tool
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| DSBGA (YFQ) | 12 | Ultra Librarian |
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