LM3644 LED Driver Datasheet

LM3644 Datasheet, PDF, Equivalent


Part Number

LM3644

Description

Dual 1.5-A Current Source Camera Flash LED Driver

Manufacture

etcTI

Total Page 30 Pages
Datasheet
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LM3644
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LM3644, LM3644TT
SNVSA52E – AUGUST 2014 – REVISED SEPTEMBER 2016
LM3644 Dual 1.5-A Current Source Camera Flash LED Driver
1 Features
1 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)
2 Applications
• Camera Phone White LED Flash
• Digital Still Cameras
• Fire-Alarm Notification
• Emergency Strobe Lighting
• Intruder Alert Notification
• Barcode Scanners
• Handheld Data Terminals
3 Description
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.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (MAX)
LM3644
DSBGA (12)
1.69 mm x 1.31 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Simplified Schematic
1 PH
2.5V to 5.5V
10 PF
IN SW OUT
LM3644
10 PF
LED1
TORCH/TEMP
STROBE
HWEN
TX
SDA
SCL
LED2
GND
Flash
LED
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.

LM3644
LM3644, LM3644TT
SNVSA52E – AUGUST 2014 – REVISED SEPTEMBER 2016
www.ti.com
Table of Contents
1 Features .................................................................. 1
2 Applications ........................................................... 1
3 Description ............................................................. 1
4 Revision History..................................................... 2
5 Device Comparison Table..................................... 2
6 Pin Configuration and Functions ......................... 3
7 Specifications......................................................... 4
7.1 Absolute Maximum Ratings ...................................... 4
7.2 ESD Ratings ............................................................ 4
7.3 Recommended Operating Conditions....................... 4
7.4 Thermal Information .................................................. 4
7.5 Electrical Characteristics........................................... 5
7.6 Timing Requirements ............................................... 6
7.7 Switching Characteristics .......................................... 6
7.8 Typical Characteristics .............................................. 6
8 Detailed Description ............................................ 12
8.1 Overview ................................................................. 12
8.2 Functional Block Diagram ...................................... 13
8.3 Feature Description ................................................ 13
8.4 Device Functioning Modes...................................... 15
8.5 Programming........................................................... 19
8.6 Register Descriptions .............................................. 21
9 Applications and Implementation ...................... 25
9.1 Application Information............................................ 25
9.2 Typical Application ................................................. 25
10 Power Supply Recommendations ..................... 31
11 Layout................................................................... 31
11.1 Layout Guidelines ................................................. 31
11.2 Layout Example ................................................... 32
12 Device and Documentation Support ................. 33
12.1 Device Support...................................................... 33
12.2 Related Documentation......................................... 33
12.3 Trademarks ........................................................... 33
12.4 Electrostatic Discharge Caution ............................ 33
12.5 Glossary ................................................................ 33
13 Mechanical, Packaging, and Orderable
Information ........................................................... 34
4 Revision History
Changes from Revision D (September 2015) to Revision E
Page
• Added several additional Applications; updated Device and Documentation Support with 2 new subsections ................... 1
Changes from Revision C (April 2015) to Revision D
Page
• Changed 0x00 to 0x02 - typo ............................................................................................................................................... 21
• Changed 0x40 to 0x04 - typo ............................................................................................................................................... 21
Changes from Revision B (November 2014) to Revision C
Page
• Added information about LM3644TT option ........................................................................................................................... 1
• Changed Handling Ratings to ESD Ratings; moved storage temp to Ab Max ..................................................................... 4
• Added full Thermal Information information .......................................................................................................................... 4
Changes from Revision A (October 2013) to Revision B
Page
• Changed '011' to '000' - typo ................................................................................................................................................ 24
Changes from Original (August 2014) to Revision A
Page
• Changed title from "1.5A Synchronous Boost White LED Driver with High Side Current Sources " to "Dual 1.5-A
Current Source Camera Flash LED Driver" ........................................................................................................................... 1
• Added Note to beginning of Applications and Implementations section .............................................................................. 25
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Product Folder Links: LM3644 LM3644TT


Features Product Folder Sample & Buy Technical Documents Tools & Software Support & Community LM3644, LM3644TT SNVSA52E AUGUST 2014 – REVISED SEPTEMBER 201 6 LM3644 Dual 1.5-A Current Source Came ra Flash LED Driver 1 Features •1 Du al Independent 1.5-A LED Current Source Programmability • Accurate and Progr ammable LED Current Range from 1.4 mA t o 1.5 A • Torch Currents up to 360 mA (LM3644TT) • Flash Timeout Values up to 1.6 seconds (LM3644TT) • Optimize d Flash LED Current During Low Battery Conditions (IVFM) • > 85% Efficiency in Torch Mode (at 100 mA) and Flash Mod e (at 1 A to 1.5 A) • Grounded Cathod e LED Operation for Improved Thermal Ma nagement • Small Solution Size: < 16 mm2 • Hardware Strobe Enable (STROBE) • Synchronization Input for RF Power Amplifier Pulse Events (TX) • Hardwa re Torch Enable (TORCH/TEMP) • Remote NTC Monitoring (TORCH/TEMP) • 400-kH z I2C-Compatible Interface – LM3644 ( I2C Address = 0x63) 2 Applications • Camera Phone White LED Flash • Digital Still Cameras • Fir.
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