NSC LM3404, LM3404MRX Datasheet

June 2007

LM3404/04HV

1.0A Constant Current Buck Regulator for Driving High
Power LEDs

General Description

The LM3404/04HV are monolithic switching regulators de­signed 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, 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 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

© 2007 National Semiconductor Corporation 202054 www.national.com

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

Connection Diagrams

20205402

8-Lead Plastic SO-8 Package

NS Package Number M08A

20205456

8-Lead Plastic PSOP-8 Package

NS Package Number MRA08B

Ordering Information

Order Number Package Type NSC Package Drawing Supplied As

LM3404MA

SO-8 M08A

95 units in anti-static rails

LM3404MAX 2500 units on tape and reel

LM3404HVMA 95 units in anti-static rails

LM3404HVMAX 2500 units on tape and reel

LM3404MR

PSOP-8 MRA08B

95 units in anti-static rails

LM3404MRX 2500 units on tape and reel

LM3404HVMR 95 units in anti-static rails

LM3404HVMRX 2500 units on tape and reel

Pin Descriptions

Pin(s) Name Description Application Information

1 SW Switch pin Connect this pin to the output inductor and Schottky diode.

2 BOOT MOSFET drive bootstrap pin Connect a 10 nF ceramic capacitor from this pin to SW.

3 DIM Input for PWM dimming 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.

4 GND Ground pin Connect this pin to system ground.

5 CS Current sense feedback pin Set the current through the LED array by connecting a resistor from

this pin to ground.

6 RON On-time control pin A resistor connected from this pin to VIN sets the regulator controlled

on-time.

7 VCC Output of the internal 7V linear

regulator

Bypass this pin to ground with a minimum 0.1 µF ceramic capacitor
with X5R or X7R dielectric.

8 VIN Input voltage pin Nominal operating input range for this pin is 6V to 42V (LM3404) or 6V

to 75V (LM3404HV).

DAP GND Thermal Pad Connect to ground. Place 4-6 vias from 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 -0.3V to 45V
BOOT to GND -0.3V to 59V
SW to GND -1.5V to 45V
BOOT to VCC -0.3V to 45V
BOOT to SW -0.3V to 14V
VCC to GND -0.3V to 14V
DIM to GND -0.3V to 7V
CS to GND -0.3V to 7V
RON to GND -0.3V to 7V
Junction Temperature 150°C

Storage Temp. Range -65°C to 125°C
ESD Rating (Note 2) 2kV
Soldering Information
Lead Temperature (Soldering,

10sec) 260°C
Infrared/Convection Reflow (15sec) 235°C

Operating Ratings (LM3404)

(Note 1)

V

IN

6V to 42V

Junction Temperature Range −40°C to +125°C

Thermal Resistance θ

JA

(SO-8 Package) 155°C/W

Thermal Resistance θ

JA

(PSOP-8 Package) (Note 5) 50°C/W

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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

-0.3V to 76V
BOOT to GND -0.3V to 90V
SW to GND -1.5V to 76V
BOOT to VCC -0.3V to 76V
BOOT to SW -0.3V to 14V
VCC to GND -0.3V to 14V
DIM to GND -0.3V to 7V
CS to GND -0.3V to 7V
RON to GND -0.3V to 7V
Junction Temperature 150°C

Storage Temp. Range -65°C to 125°C
ESD Rating (Note 2) 2kV
Soldering Information
Lead Temperature (Soldering,

10sec) 260°C
Infrared/Convection Reflow (15sec) 235°C

Operating Ratings (LM3404HV)

(Note 1)

V

IN

6V to 75V

Junction Temperature Range −40°C to +125°C

Thermal Resistance θ

JA

(SO-8 Package) 155°C/W

Thermal Resistance θ

JA

(PSOP-8 Package) (Note 5) 50°C/W

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LM3404/LM3404HV

Electrical Characteristics V

IN

= 24V unless otherwise indicated. Typicals and limits appearing in plain type apply
for TA = TJ = +25°C. (Note 4) Limits appearing in boldface type apply over full Operating Temperature Range. Datasheet min/
max specification limits are guaranteed by design, test, or statistical analysis.

LM3404

Symbol Parameter Conditions Min Typ Max Units

SYSTEM PARAMETERS

t

ON-1

On-time 1

VIN = 10V, RON = 200 kΩ

2.1 2.75 3.4 µs

t

ON-2

On-time 2

VIN = 40V, RON = 200 kΩ

515 675 835 ns

LM3404HV

Symbol Parameter Conditions Min Typ Max Units

SYSTEM PARAMETERS

t

ON-1

On-time 1

VIN = 10V, RON = 200 kΩ

2.1 2.75 3.4 µs

t

ON-2

On-time 2

VIN = 70V, RON = 200 kΩ

325 415 505 ns

LM3404/LM3404HV

Symbol Parameter Conditions Min Typ Max Units

REGULATION AND OVER-VOLTAGE COMPARATORS

V

REF-REG

CS Regulation Threshold CS Decreasing, SW turns on 194 200 206 mV

V

REF-0V

CS Over-voltage Threshold CS Increasing, SW turns off 300 mV

I

CS

CS Bias Current CS = 0V 0.1 µA

SHUTDOWN

V

SD-TH

Shutdown Threshold RON / SD Increasing 0.3 0.7 1.05 V

V

SD-HYS

Shutdown Hysteresis RON / SD Decreasing 40 mV

OFF TIMER

t

OFF-MIN

Minimum Off-time CS = 0V 270 ns

INTERNAL REGULATOR

V

CC-REG

VCC Regulated Output 6.4 7 7.4 V

V

IN-DO

VIN - V

CC

ICC = 5 mA, 6.0V < VIN < 8.0V 300 mV

V

CC-BP-TH

VCC Bypass Threshold VIN Increasing 8.8 V

V

CC-BP-HYS

VCC Bypass Hysteresis VIN Decreasing 230 mV

V

CC-Z-6

VCC Output Impedance
(0 mA < ICC < 5 mA)

VIN = 6V 55

Ω

V

CC-Z-8

VIN = 8V 50

V

CC-Z-24

VIN = 24V 0.4

V

CC-LIM

VCC Current Limit (Note 3) VIN = 24V, VCC = 0V 16 mA

V

CC-UV-TH

VCC Under-voltage Lock-out
Threshold

VCC Increasing 5.3 V

V

CC-UV-HYS

VCC Under-voltage Lock-out
Hysteresis

VCC Decreasing 150 mV

V

CC-UV-DLY

VCC Under-voltage Lock-out
Filter Delay

100 mV Overdrive 3 µs

I

IN-OP

I

IN

Operating Current Non-switching, CS = 0.5V 625 900 µA

I

IN-SD

IIN Shutdown Current RON / SD = 0V 95 180 µA

CURRENT LIMIT

I

LIM

Current Limit Threshold 1.2 1.5 1.8 A

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LM3404/LM3404HV

Symbol Parameter Conditions Min Typ Max Units

DIM COMPARATOR

V

IH

Logic High DIM Increasing 2.2 V

V

IL

Logic Low DIM Decreasing 0.8 V

I

DIM-PU

DIM Pull-up Current DIM = 1.5V 80 µA

MOSFET AND DRIVER

R

DS-ON

Buck Switch On Resistance ISW = 200mA, BST-SW = 6.3V 0.37 0.75

Ω

V

DR-UVLO

BST Under-voltage Lock-out
Threshold

BST–SW Increasing 1.7 3 4 V

V

DR-HYS

BST Under-voltage Lock-out
Hysteresis

BST–SW Decreasing 400 mV

THERMAL SHUTDOWN

T

SD

Thermal Shutdown Threshold 165 °C

T

SD-HYS

Thermal Shutdown Hysteresis 25 °C

THERMAL RESISTANCE

θ

JA

Junction to Ambient SOIC-8 Package 155 °C/W

PSOP-8 Package (Note 5) 50

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see Electrical Characteristics.

Note 2: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin.

Note 3: VCC provides self bias for the internal gate drive and control circuits. Device thermal limitations limit external loading.

Note 4: Typical specifications represent the most likely parametric norm at 25°C operation.

Note 5: θJA of 50°C/W with DAP soldered to a minimum of 2 square inches of 1oz. copper on the top or bottom PCB layer.

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LM3404/LM3404HV

Typical Performance Characteristics

V

REF

vs Temperature (VIN = 24V)

20205450

V

REF

vs VIN, LM3404 (TA = 25°C)

20205451

V

REF

vs VIN, LM3404HV (TA = 25°C)

20205452

Current Limit vs Temperature (VIN = 24V)

20205453

Current Limit vs VIN, LM3404 (TA = 25°C)

20205454

Current Limit vs VIN, LM3404HV (TA = 25°C)

20205455

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LM3404/LM3404HV

TON vs VIN,

RON = 100 kΩ (TA = 25°C)

20205435

TON vs VIN,
(TA = 25°C)

20205436

TON vs VIN,
(TA = 25°C)

20205437

TON vs RON, LM3404

(TA = 25°C)

20205444

TON vs RON, LM3404HV

(TA = 25°C)

20205438

VCC vs V

IN

(TA = 25°C)

20205439

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LM3404/LM3404HV