LM3405A - 1.6MHz, 1A Constant Current Buck LED Driver with Internal Compensation in Tiny SOT23 and eMSOP Package

LM3405A - 1.6MHz, 1A Constant Current Buck LED Driver with Internal Compensation in Tiny SOT23 and eMSOP Package from the PowerWise® Family

Datasheet	Packaging	Samples & Pricing	Eval. Boards	Reliability	Reference Designs	Application Notes	Knowledge Base

Features

•	V_IN operating range of 3V to 22V
•	Drives up to 5 High-Brightness LEDs in series at 1A
•	Thin SOT23-6 package & eMSOP8 with exposed DAP
•	1.6MHz switching frequency
•	EN/DIM input for enabling and PWM dimming of LEDs
•	300mΩ NMOS switch
•	40nA shutdown current at V_IN = 5V
•	Internally compensated current-mode control
•	Cycle-by-cycle current limit
•	Input voltage UVLO
•	Over-current protection
•	Thermal shutdown

General Description

The LM3405A is a 1A constant current buck LED driver designed to provide a simple, high efficiency solution for driving high power LEDs. More...

Applications

•	LED Driver
•	Constant Current Source
•	Industrial Lighting
•	LED Flashlights
•	LED Lightbulbs

Typical Application

click for larger image

Series zener diode from Vin

Parameters Values

Topology Buck

Input Min Voltage 3 Volt

Input Max Voltage 22 Volt

Output Range 0.2V to 20V

Output Current 1000 mA

Efficiency (peak) 92 %

Output Min 0.2 Volt

Output Max 20 Volt

Adjustable Output Yes

On/Off Pin Yes

Error Flag No

Switching Frequency 1600 kHz

Adj Switch Frequency No

Sync Pin No

Step-Down Yes

Step-Up No

Inverting No

Flyback No

RegType Switching Regulator

Temperature Min -40 deg C

Temperature Max 125 deg C

Feedback Voltage 0.2 Volt

Automotive Yes

PowerWise Yes

Typical Performance

click for larger image

Efficiency vs. LED Current for Vin = 12V, 1 and 2 LEDs

WEBENCH Live Simulation!

LM3405A
3.00 <=	V in Lower V	<=	V in Upper V	<= 22.00
Ambient Temperature			°C	<= 100
What are WEBENCH® tools?

Additional Resources

Application Notes

Block Diagram

click for larger image

temporary

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM3405A 1.6MHz, 1A Constant Current Buck LED Driver with Internal Compensation in Tiny SOT23 and eMSOP Package	516 Kbytes	23-Oct-08	Download

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Package Availability, Models, Samples & Pricing

Part Number

Package

Factory Lead Time

Models

Samples &
Electronic
Orders

Budgetary Pricing

Std
Pack
Size

Package
Marking
Format

Type

Pins

Spec.

MSL
Rating

Peak
Reflow

RoHS
Report

CAD
Symbols

Weeks

Qty

$US each

LM3405AXMKE

TSOT

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$1.10

reel
of
250

SSEB
XTT

6 weeks

N/A

LM3405AXMK

TSOT

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$1.10

reel
of
1000

SSEB
XTT

6 weeks

N/A

LM3405AXMKX

TSOT

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$1.10

reel
of
3000

SSEB
XTT

6 weeks

N/A

LM3405AXMY

MINI SOIC EXP PAD

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$1.20

reel
of
1000

ZXTT
SVSA

6 weeks

N/A

LM3405AXMYX

MINI SOIC EXP PAD

NOPB

260

RoHS

N/A

Full production

N/A

1K+

$1.20

reel
of
3500

ZXTT
SVSA

6 weeks

N/A

LM3405AEVAL

1.6MHz, 1A Constant Current Buck LED Driver with Internal Compensation in Tiny SOT-23 Package

Full production

N/A

$45.00

8 weeks

N/A

LM3405AXMYEVAL

LM3405AXMY - 1.6 MHz, 1A Constant Current Buck LED Driver with Internal Compensation in eMSOP Package

Full production

N/A

$55.00

8 weeks

N/A

General Description

The LM3405A is a 1A constant current buck LED driver designed to provide a simple, high efficiency solution for driving high power LEDs. With a 0.205V reference voltage feedback control to minimize power dissipation, an external resistor sets the current as needed for driving various types of LEDs. Switching frequency is internally set to 1.6MHz, allowing small surface mount inductors and capacitors to be used. The LM3405A utilizes current-mode control and internal compensation offering ease of use and predictable, high performance regulation over a wide range of operating conditions. With a maximum input voltage of 22V, it can drive up to 5 High-Brightness LEDs in series at 1A forward current, with the single LED forward voltage of approximately 3.7V. Additional features include user accessible EN/DIM pin for enabling and PWM dimming of LEDs, thermal shutdown, cycle-by-cycle current limit and over-current protection.

Reliability Metrics

Part Number	Process	EFR Sample Size	LTA Device Hours	FITS	MTTF (Hours)
LM3405AXMK	PVIP050	9960	855000	5	242608584
LM3405AXMKE	PVIP050	9960	855000	5	242608584
LM3405AXMKX	PVIP050	9960	855000	5	242608584
LM3405AXMY	PVIP050	9960	855000	5	242608584
LM3405AXMYX	PVIP050	9960	855000	5	242608584

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.

Reference Designs

•	RD-148 - LM3405A Reference Design for MR16 LED Bulb, 600mA

Application Notes

Title	Size in Kbytes	Date
AN-1685: Application Note 1685 LM3405A Demo Board	907 Kbytes	19-Oct-07	Download
AN-1685 (Chinese): Application Note 1685 LM3405A Demo Board	478 Kbytes
AN-1899: Application Note 1899 LM3405A eMSOP Evaluation Board	442 Kbytes	6-Jul-09	Download
AN-1899 (Chinese): Application Note 1899 LM3405A eMSOP Evaluation Board	289 Kbytes

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More Application Notes

Title	Size in Kbytes	Date
AN-1644: Application Note 1644 Powering and Dimming High-Brightness LEDs with the LM3405 Constant-Current Buck Regulator	174 Kbytes	17-Jan-08	Download
AN-1590: Application Note 1590 LM3405 Demo Board	475 Kbytes	19-Mar-07	Download

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[Information as of 7-Nov-2009]