LM3643 Flash Driver Datasheet

LM3643 Datasheet, PDF, Equivalent


Part Number

LM3643

Description

Synchronous Boost Dual LED Flash Driver

Manufacture

etcTI

Total Page 30 Pages
Datasheet
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LM3643
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LM3643, LM3643A
SNVS967A – AUGUST 2014 – REVISED NOVEMBER 2014
LM3643 Synchronous Boost Dual LED Flash Driver with 1.5-A High-Side Current Sources
1 Features
1 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)
2 Applications
Camera Phone White LED Flash
3 Description
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.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (MAX)
LM3643
DSBGA (12)
1.69 mm x 1.31 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
4 Simplified Schematic
1 2H
2.5V to 5.5V
10 2F
IN SW OUT
LM3643
10 2F
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.

LM3643
LM3643, LM3643A
SNVS967A – AUGUST 2014 – REVISED NOVEMBER 2014
www.ti.com
Table of Contents
1 Features .................................................................. 1
2 Applications ........................................................... 1
3 Description ............................................................. 1
4 Simplified Schematic............................................. 1
5 Revision History..................................................... 2
6 Device Comparison Table..................................... 2
7 Pin Configuration and Functions ......................... 3
8 Specifications......................................................... 4
8.1 Absolute Maximum Ratings ...................................... 4
8.2 Handling Ratings ...................................................... 4
8.3 Recommended Operating Conditions....................... 4
8.4 Thermal Information .................................................. 4
8.5 Electrical Characteristics........................................... 5
8.6 Timing Requirements ............................................... 5
8.7 Switching Characteristics .......................................... 5
8.8 Typical Characteristics .............................................. 6
9 Detailed Description ............................................ 10
9.1 Overview ................................................................. 10
9.2 Functional Block Diagram ...................................... 11
9.3 Feature Description ................................................ 12
9.4 Device Functioning Modes...................................... 13
9.5 Programming........................................................... 17
9.6 Register Descriptions .............................................. 19
10 Applications and Implementation...................... 23
10.1 Application Information.......................................... 23
10.2 Typical Application ............................................... 23
11 Power Supply Recommendations ..................... 29
12 Layout................................................................... 29
12.1 Layout Guidelines ................................................. 29
12.2 Layout Example ................................................... 30
13 Device and Documentation Support ................. 31
13.1 Device Support...................................................... 31
13.2 Related Documentation......................................... 31
13.3 Trademarks ........................................................... 31
13.4 Electrostatic Discharge Caution ............................ 31
13.5 Glossary ................................................................ 31
14 Mechanical, Packaging, and Orderable
Information ........................................................... 31
5 Revision History
Changes from Original (August 2014) to Revision A
Page
• Added Information about LM3643A ....................................................................................................................................... 1
• Changed 0x00 to 0x02 - typo ............................................................................................................................................... 19
• Changed '011' to '000' - typo ................................................................................................................................................ 22
6 Device Comparison Table
ORDERING PART NUMBER
LM3643YFFR
LM3643AYFFR
I2C ADDRESS
0x63
0x67
2 Submit Documentation Feedback
Product Folder Links: LM3643 LM3643A
Copyright © 2014, Texas Instruments Incorporated


Features Product Folder Sample & Buy Technical Documents Tools & Software Support & Community LM3643, LM3643A SNVS967A – AUGUST 2014 – REVISED NOVEMBER 2014 LM3643 Synchronous Boost Dual LED Flash Driver with 1.5-A High-Side Current So urces 1 Features •1 1.5 A Total Allo wed LED Current During Operation (ILED1 + ILED2 = 1.5 A) • Dual Independent LED Current Source Programmability • Accurate and Programmable LED Current R ange from 1.4 mA to 1.5 A • Optimized Flash LED Current During Low Battery C onditions (IVFM) • > 85% Efficiency i n Torch Mode (@ 100 mA) and Flash Mode (@1 A to 1.5 A) • Grounded Cathode LE D Operation for Improved Thermal Manage ment • Small Solution Size: < 16 mm2 • Hardware Strobe Enable (STROBE) • Synchronization Input for RF Power Amp lifier Pulse Events (TX) • Hardware T orch Enable (TORCH/TEMP) • Remote NTC Monitoring (TORCH/TEMP) • 400-kHz I2 C-Compatible Interface – LM3643 (I2C Address = 0x63) – LM3643A (I2C Address = 0x67) 2 Applications Camera Phone White LED Flash 3.
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