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

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

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Series zener diode from Vin

Parametric Table expand

Parametric Table collapse

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 %

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 1600000 Hz

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 Selection Guide Yes

PowerWise Yes

View Using Catalog

Typical Performance

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

WEBENCH Live Simulation!

LM3405A LED WEBENCH® Custom Design/Analyze/Build It/Test It
3.00 <=	V in Lower V	<=	V in Upper V	<= 22.00
Select LED Manufacturer: and Part #

LED Properties: Vf: If: Rd:
#Series		#Parallel
V _LED	V	I _LED	A	<= 1.0
Ambient Temperature			°C	<= 100
Try full version of LED WEBENCH®

Additional Resources

Application Notes (see below)

Block Diagram

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temporary

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM3405A 1.6MHz, 1A Constant Current Buck LED Driver with Internal Compensation in Tiny SOT23 Package	496 Kbytes	19-Oct-07	View Online	Download	Receive via Email

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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

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

LM3405AXMKE

TSOT

NOPB

260

RoHS

N/A

Full production

N/A

500+

$1.24

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

8 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

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	Early Failure Rate - Rejects	Sample Size (EFR)	PPM *	Rel. Rejects	Device Hours	Long Term Failure Rates (FITS)	MTTF
LM3405AXMK	PVIP050	0	8430	0	0	495000	8	140457601
LM3405AXMKE	PVIP050	0	8430	0	0	495000	8	140457601
LM3405AXMKX	PVIP050	0	8430	0	0	495000	8	140457601

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-1545: Application Note 1545 LM3404/LM3404HV Evaluation Board	661 Kbytes	7-Jan-08	View Online	Download	Receive via Email
AN-1500: Application Note 1500 LM3402/02HV Demo Board	29977 Kbytes	5-Jun-07	View Online	Download	Receive via Email
AN-1500 (Chinese): Application Note 1500 LM3402/02HV Demo Board	531 Kbytes
AN-1839: Application Note 1839 LM3402/LM3404 Fast Dimming and True Constant LED Current Evaluation Board	1145 Kbytes	18-Aug-08	View Online	Download	Receive via Email
AN-1585: Application Note 1585 LM3402 and LM3404 High Power PSOP-8 Evaluation Board	493 Kbytes	4-Oct-07	View Online	Download	Receive via Email
AN-1629: Application Note 1629 Thermal Performance of the LM3404/04HV in SO-8 and PSOP-8 Packages	410 Kbytes	31-May-07	View Online	Download	Receive via Email
AN-1629 (Chinese): Application Note 1629 Thermal Performance of the LM3404/04HV in SO-8 and PSOP-8 Packages	380 Kbytes
AN-1657: Application Note 1657 LM3401 Demo Board	891 Kbytes	29-Jul-08	View Online	Download	Receive via Email
AN-1657 (Chinese): Application Note 1657 LM3401 Demo Board	351 Kbytes
AN-1644: Application Note 1644 Powering and Dimming High-Brightness LEDs with the LM3405 Constant-Current Buck Regulator	174 Kbytes	17-Jan-08	View Online	Download	Receive via Email
AN-1763: Application Note 1763 LM3407 Evaluation Board Reference Design	399 Kbytes	18-Jan-08	View Online	Download	Receive via Email
AN-1685: Application Note 1685 LM3405A Demo Board	907 Kbytes	19-Oct-07	View Online	Download	Receive via Email
AN-1590: Application Note 1590 LM3405 Demo Board	475 Kbytes	19-Mar-07	View Online	Download	Receive via Email

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[Information as of 6-Sep-2008]