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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 de-
signed to deliver 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-parallel connected LED
arrays of varying number and type. LED dimming via pulse
width modulation (PWM), broken/open LED protection, low-
power shutdown and thermal shutdown complete the feature
set.
Features
■
■
■
■
■
■
■
■
Integrated 1.0A MOSFET
V
IN
Range 6V to 42V (LM3404)
V
IN
Range 6V to 75V (LM3404HV)
1.2A Output Current Over Temperature
Cycle-by-Cycle Current Limit
No Control Loop Compensation Required
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
202054
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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 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
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 sense feedback 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 to system 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 vias from DAP to bottom layer ground
plane.
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2
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
Junction Temperature
-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)
V
IN
Junction Temperature Range
Thermal Resistance
θ
JA
(SO-8 Package)
Thermal Resistance
θ
JA
(PSOP-8 Package) (Note
5)
6V to 42V
−40°C to +125°C
155°C/W
50°C/W
3
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LM3404/LM3404HV
Absolute Maximum Ratings
(LM3404HV)
(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
Junction Temperature
-0.3V to 76V
-0.3V to 90V
-1.5V to 76V
-0.3V to 76V
-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 (LM3404HV)
(Note
1)
V
IN
Junction Temperature Range
Thermal Resistance
θ
JA
(SO-8 Package)
Thermal Resistance
θ
JA
(PSOP-8 Package) (Note
5)
6V to 75V
−40°C to +125°C
155°C/W
50°C/W
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