LM3404/04HV
1.0A Constant Current Buck Regulator for Driving High
Power LEDs
General Description
The LM3404/04HV are monolithic switching regulators de-
signed to deliver constant currents to high power LEDs. Ideal
for automotive, industrial, and general lighting applications,
they contain a high-side NFET switch with a minimum over-
temperature current limit of 1.2A for step-down (Buck) regu-
lators. Hysteretic control with controlled on-time coupled with
an external resistor allow the converter output voltage to
adjust as needed to deliver constant current to series and
series-parallel connected LED arrays of varying number and
type. Output current dimming via PWM, broken/open LED
protection, low-power shutdown and thermal shutdown com-
plete the feature set.
Features
n
Integrated 1.2A NFET
n
V
IN
Range 6V to 42V (LM3404)
n
V
IN
Range 6V to 75V (LM3404HV)
n
1.2A Output Current Over Temperature
n
Cycle-by-Cycle Current Limit
n
No Control Loop Compensation Required
n
Separate PWM Dimming and Low Power Shutdown
n
Supports all-ceramic output capacitors and
capacitor-less outputs
n
Thermal shutdown protection
n
SO-8 Package
Applications
n
LED Driver
n
Constant Current Source
n
Automotive Lighting
n
General Illumination
n
Industrial Lighting
Typical Application
20205401
Connection Diagram
20205402
8-Lead Plastic SO-8 Package
NS Package Number M08A
ADVANCE INFORMATION
October 2006
LM3404/04HV
1.0A
Constant
Current
Buck
Regulator
for
Driving
High
Power
LEDs
2006 National Semiconductor Corporation
DS202054
www.national.com
Physical Dimensions
inches (millimeters) unless otherwise noted
SO-8 Package
NS Package Number M08A
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LM3404/04HV
1.0A
Constant
Current
Buck
Regulator
for
Driving
High
Power
LEDs
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