LM3501

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SNVS230C – DECEMBER 2003 – REVISED MAY 2013

PIN DESCRIPTIONS

Pin

Name

Function

A1

AGND

Analog ground.

B1

VIN

Analog and Power supply input.

C1

VOUT

PMOS source connection for synchronous rectification.

C2

VSW

Switch pin. Drain connections of both NMOS and PMOS power devices.

C3

GND

Power Ground.

B3

FB

Output voltage feedback connection.

A3

CNTRL

Analog LED current control.

A2

SHDN

Shutdown control pin.

AGND (pin A1): Analog ground pin

The analog ground pin should tie directly to the GND pin.

VIN (pin B1): Analog and Power supply pin

Bypass this pin with a capacitor, as close to the device as possible, connected between the

VIN and GND pins.

VOUT (pin C1): Source connection of internal PMOS power device

Connect the output capacitor between the VOUT and GND pins as close as possible to the

device.

VSW (pin C2): Drain connection of internal NMOS and PMOS switch devices

Keep the inductor connection close to this pin to minimize EMI radiation.

GND (pin C3): Power ground pin

Tie directly to ground plane.

FB (pin B3): Output voltage feedback connection

Set the primary White LED network current with a resistor from the FB pin to GND. Keep the

current setting resistor close to the device and connected between the FB and GND pins.

CNTRL (pin A3): Analog control of LED current

A voltage above 125 mV will begin to regulate the LED current. Decreasing the voltage

below 75 mV will turn off the LEDs.

SHDN (pin A2): Shutdown control pin

Disable the device with a voltage less than 0.3V and enable the device with a voltage

greater than 1.1V. The white LED current can be controlled using a PWM signal at this pin.

There is an internal pull down on the SHDN pin, the device is in a normally off state.

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

Copyright © 2003–2013, Texas Instruments Incorporated

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