Description

The PAM2861 is a continuous mode inductive step-down converter,

designed for driving single or multiple series connected LEDs

efficiently from a voltage source higher than the LED voltage. The

device operates from an input supply between 6V and 40V and

provides an externally adjustable output current of up to 1A.

Depending upon supply voltage and external components, this can

provide up to 30 watts of output power.

The PAM2861 includes the output switch and a high-side output

current sensing circuit, which uses an external resistor to set the

nominal average output current.

Output current can be adjusted below the set value, by applying an

external control signal to the VSET pin.

The VSET pin will accept either a DC voltage or a PWM waveform.

The soft-start time can be increased using an external capacitor from

the VSET pin to ground. Applying a voltage of 0.2V or lower to the

VSET pin turns the output off and switches the device into a low

current standby state. 

Features

 Simple Low Parts Count

 Internal 40V NDMOS Switch

 1A Output Current

 Single Pin On/Off and Brightness Control Using DC Voltage or

PWM

 Soft-Start

 High Efficiency (up to 97%)

 Wide Input Voltage Range: 6V to 40V

 Output Shutdown

 Open LED Protection

 Short LED Protection

 Up to 1MHz Switching Frequency

 Inherent Open-Circuit LED Protection

 Typical 5% Output Current Accuracy

 Pb-free TSOT25 and SOT89-5 Packages 

Applications

 Low voltage halogen replacement LEDs

 Low voltage industrial lighting

 LED back-side lighting

 Illuminated signs 

Functional Block Diagram

Typical Performance Characteristics (@TA = +25°C, VIN = 16V, unless otherwise specified.)