LM3402/HV 0.5-A Constant Current Buck Regulator for Driving High Power LEDs
1 Features
- Integrated 0.5-A N-channel MOSFET
- VIN Range from 6 V to 42 V (LM3402)
- VIN Range from 6 V to 75 V (LM3402HV)
- 500 mA 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
- VSSOP, SO PowerPAD™ Packages
2 Applications
- LED Drivers
- Constant Current Source
- Automotive Lighting
- General Illumination
- Industrial Lighting
3 Description
The LM3402/HV 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 735 mA (typical) for step-down (Buck) regulators. Hysteretic control with controlled ON-time coupled with an external resistor allow the converter output voltage to adjust as needed to deliver a constant current to series and series - parallel connected arrays of LEDs of varying number and type, LED dimming by pulse width modulation (PWM), broken/open LED protection, low-power shutdown and thermal shutdown complete the feature set.
Device Information(1)
| PART NUMBER | PACKAGE | BODY SIZE (NOM) |
|---|---|---|
| LM3402/HV | VSSOP (8) | 3.00 mm × 3.00 mm |
| HSOP (8) | 4.89 mm × 3.90 mm |
- For all available packages, see the orderable addendum at the end of the data sheet.
Typical Application Diagram
4 Revision History
Changes from E Revision (April 2013) to F Revision
- Added ESD Ratings and Timing Requirements tables, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section Go
Changes from D Revision (May 2013) to E Revision
- Changed layout of National Data Sheet to TI formatGo
5 Pin Configuration and Functions
Pin Functions
| PIN | I/O | DESCRIPTION | |
|---|---|---|---|
| NO. | NAME | ||
| 1 | SW | O | Switch pin. Connect this pin to the output inductor and Schottky diode. |
| 2 | BOOT | O | MOSFET drive bootstrap pin. Connect a 10-nF ceramic capacitor from this pin to SW. |
| 3 | DIM | I | Input for PWM dimming. Connect a logic-level PWM signal to this pin to enable and 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 | I | Current sense feedback pin. Set the current through the LED array by connecting a resistor from this pin to ground. |
| 6 | RON | I | ON-time control pin. A resistor connected from this pin to VIN sets the regulator controlled ON-time. |
| 7 | VCC | O | Output of the internal 7-V linear regulator. Bypass this pin to ground with a minimum 0.1-µF ceramic capacitor with X5R or X7R dielectric. |
| 8 | VIN | I | Input voltage pin. Nominal operating input range for this pin is 6 V to 42 V (LM3402) or 6 V to 75 V (LM3402HV). |
| DAP | — | Thermal Pad. Connect to ground. Place 4-6 vias from DAP to bottom layer ground plane. | |
