UM1350_14 Datasheet, PDF (1/15 Pages) Union Semiconductor, Inc. – 350mA, LED Lighting Driver

UM1350
350mA, LED Lighting Driver
UM1350 SOT23-5
General Description
The UM1350 is capable of driving single or multiple series connected LEDs efficiently from a
voltage source higher than the LED voltage. This step-down converter provides an externally
adjustable output current of up to 350mA from an input supply between 6V and 30V. It can even
reach 8 watts of output power, depending on supply voltage and external components. The
UM1350 consists of an output switch and a high-side output current sensing circuit that uses an
external resistor to set the nominal average output current. Through applying an external control
signal to the VSET pin, it can adjust the output current below the set value. The VSET pin will
accept either a DC voltage or a PWM waveform to provide a continuous or a gated output current.
The chip contains a PWM filter which provides a soft-start feature by controlling the rise of
input/output current. It can raise the soft-start by 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.
The UM1350 is available in a low profile SOT23-5 package.
Applications
Features
 MR16 and General Lighting
 Automotive Lighting
 Low Voltage Industrial Lighting
 LED Back Lighting
 Illuminated Signs
 Built in Thermal and Over Current Shut down
 Internal 40V NDMOS Switch
 350mA Output Current
 Single Pin on/off and Dimming Control Using
DC Voltage or PWM at VSET Pin.
 Internal PWM Filter
 Soft-Start
 High Efficiency (up to 95%)
 Wide Input Voltage Range: 6V to 40V
 40V Transient Capability
 Output Shutdown
 Up to 1MHz Switching Frequency
 Inherent Open-Circuit LED Protection
 Typical 5% Output Current Accuracy
Pin Configurations
Top View
M: Month Code
UM1350
SOT23-5
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http://www.union-ic.com Rev.03 Nov.2014
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