Datasheet

ManualsBrandsDiodes Incorporated ManualsDriversLED Driver IC SOT-89-5

PAM2861

Document number: DSxxxxx Rev. 1 - 1

1 of 12

www.diodes.com

July 2013

PAM2861

Product Line o

Diodes Incorporated

1A LED DRIVER WITH INTERNAL SWITCH

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

Pin Assignments

Applications

 Low voltage halogen replacement LEDs

 Low voltage industrial lighting

 LED back-side lighting

 Illuminated signs

Top View

TSOT25

Summary of content (12 pages)

PAGE 1
A Product Line of Diodes Incorporated PAM2861 1A LED DRIVER WITH INTERNAL SWITCH Description Pin Assignments The PAM2861 is a continuous mode inductive step-down converter, Top View TSOT25 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.
PAGE 2
A Product Line of Diodes Incorporated PAM2861 Typical Applications Circuit Pin Descriptions Pin Number 1 2 Pin Name LX GND 3 VSET 4 ISENSE 5 VIN Function Drain of NDMOS switch. Ground (0V) • Multi-function On/Off and brightness control pin: • Leave floating for normal operation. • Drive to voltage below 0.2V to turn off output current • Drive with DC voltage (0.3V < VSET< 2.
PAGE 3
A Product Line of Diodes Incorporated PAM2861 Functional Block Diagram Absolute Maximum Ratings (@TA = +25°C, unless otherwise specified.) These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability. All voltages are with respect to ground. Parameter Input Voltage Range Rating -0.
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A Product Line of Diodes Incorporated PAM2861 Thermal Information Parameter Thermal Resistance (Junction to Ambient) Thermal Resistance (Junction to Case) Package TSOT25 SOT89-5 TSOT25 SOT89-5 Symbol θJA θJC Max 250 160 130 45 Unit °C/W Electrical Characteristics (@TA = +25°C, VIN = 16V, unless otherwise specified.) Parameter Input Voltage Symbol Test Conditions Min Typ 6 VIN 40 333 RS = 0.3Ω Output Current ILED RS = 0.
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A Product Line of Diodes Incorporated PAM2861 Typical Performance Characteristics (@TA = +25°C, VIN = 16V, unless otherwise specified.) PAM2861 Document number: DSxxxxx Rev. 1 - 1 5 of 12 www.diodes.
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A Product Line of Diodes Incorporated PAM2861 Typical Performance Characteristics (cont.) (@TA = +25°C, VIN = 16V, unless otherwise specified.) PAM2861 Document number: DSxxxxx Rev. 1 - 1 6 of 12 www.diodes.
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A Product Line of Diodes Incorporated PAM2861 Typical Performance Characteristics (cont.) (@TA = +25°C, CIN = 10µF, CO = 10µF, L = 4.7µH, unless otherwise specified.) PAM2861 Document number: DSxxxxx Rev. 1 - 1 7 of 12 www.diodes.
PAGE 8
A Product Line of Diodes Incorporated PAM2861 Application Information Setting Nominal Average Output Current with External Resistor RS The nominal average output current in the LED(s) is determined by the value of the external current sense resistor (RS) connected between VIN and ISENSE and is given by: IOUT(NOM)  0 .1 RS The table below gives values of nominal average output current for several preferred values of current setting resistor (RS) in the typical application circuit shown on page 1.
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A Product Line of Diodes Incorporated PAM2861 Application Information (cont.) Diode Selection For maximum efficiency and performance, the rectifier (D1) should be a fast low capacitance Schottky diode with low reverse leakage at the maximum operating voltage and temperature. They also provide better efficiency than silicon diodes, due to a combination of lower forward voltage and reduced recovery time.
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A Product Line of Diodes Incorporated PAM2861 Package Outline Dimensions (All dimensions in mm.) TSOT25 PAM2861 Document number: DSxxxxx Rev. 1 - 1 10 of 12 www.diodes.
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A Product Line of Diodes Incorporated PAM2861 Package Outline Dimensions (cont.) (All dimensions in mm.) SOT89-5 PAM2861 Document number: DSxxxxx Rev. 1 - 1 11 of 12 www.diodes.
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A Product Line of Diodes Incorporated PAM2861 IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).