Electronica

LM3404,LM3404HV

LM3404/04HV 1.0A Constant Current Buck Regulator for Driving High Power LEDs

Literature Number: SNVS465E

LM3404/04HV 1.0A Constant Current Buck Regulator for Driving High Power LEDs

February 8, 2010

LM3404/04HV 1.0A Constant Current Buck Regulator for Driving High Power LEDs
General Description
The LM3404/04HV are monolithic switching regulators designed todeliver constant currents to high power LEDs. Ideal for automotive, industrial, and general lighting applications, they contain a high-side N-channel MOSFET switch with a current limit of 1.5A (typical) for step-down (Buck) regulators. Hysteretic controlled on-time and an external resistor allow the converter output voltage to adjust as needed to deliver a constant current to series and series-parallelconnected LED arrays of varying number and type. LED dimming via pulse width modulation (PWM), broken/open LED protection, lowpower shutdown and thermal shutdown complete the feature set.

Features
■ ■ ■ ■ ■ ■ ■ ■
Integrated 1.0A MOSFET VIN Range 6V to 42V (LM3404) VIN Range 6V to 75V (LM3404HV) 1.2A Output Current Over Temperature Cycle-by-Cycle Current Limit No Control Loop CompensationRequired Separate PWM Dimming and Low Power Shutdown Supports all-ceramic output capacitors and capacitor-less outputs ■ Thermal shutdown protection ■ SO-8 Package, PSOP-8 Package

Applications
■ ■ ■ ■ ■
LED Driver Constant Current Source Automotive Lighting General Illumination Industrial Lighting

Typical Application

20205401

© 2010 National Semiconductor Corporation

202054www.national.com

LM3404/LM3404HV

Connection Diagrams

20205456

20205402

8-Lead Plastic PSOP-8 Package NS Package Number MRA08B

8-Lead Plastic SO-8 Package NS Package Number M08A

Ordering Information
Order Number LM3404MA LM3404MAX LM3404HVMA LM3404HVMAX LM3404MR LM3404MRX LM3404HVMR LM3404HVMRX PSOP-8 MRA08B SO-8 M08A Package Type NSC Package Drawing Supplied As 95 units inanti-static rails 2500 units on tape and reel 95 units in anti-static rails 2500 units on tape and reel 95 units in anti-static rails 2500 units on tape and reel 95 units in anti-static rails 2500 units on tape and reel

Pin Descriptions
Pin(s) 1 2 3 4 5 6 7 8 DAP Name SW BOOT DIM GND CS RON VCC VIN GND Description Switch pin MOSFET drive bootstrap pin Input for PWM dimming Ground pin Current sensefeedback pin On-time control pin Output of the internal 7V linear regulator Input voltage pin Thermal Pad Application Information Connect this pin to the output inductor and Schottky diode. Connect a 10 nF ceramic capacitor from this pin to SW. Connect a logic-level PWM signal to this pin to enable/disable the power MOSFET and reduce the average light output of the LED array. Connect this pin tosystem ground. Set the current through the LED array by connecting a resistor from this pin to ground. A resistor connected from this pin to VIN sets the regulator controlled on-time. Bypass this pin to ground with a minimum 0.1 µF ceramic capacitor with X5R or X7R dielectric. Nominal operating input range for this pin is 6V to 42V (LM3404) or 6V to 75V (LM3404HV). Connect to ground. Place 4-6 viasfrom DAP to bottom layer ground plane.

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LM3404/LM3404HV

Absolute Maximum Ratings (LM3404) (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VIN to GND BOOT to GND SW to GND BOOT to VCC BOOT to SW VCC to GND DIM to GND CS to GND RON to GND JunctionTemperature -0.3V to 45V -0.3V to 59V -1.5V to 45V -0.3V to 45V -0.3V to 14V -0.3V to 14V -0.3V to 7V -0.3V to 7V -0.3V to 7V 150°C

Storage Temp. Range ESD Rating (Note 2) Soldering Information Lead Temperature (Soldering, 10sec) Infrared/Convection Reflow (15sec)

-65°C to 125°C 2kV

260°C 235°C

Operating Ratings (LM3404)
(Note 1) VIN Junction Temperature Range Thermal Resistance θJA...