AN-1876 Datasheet, PDF (1/5 Pages) Texas Instruments – The LM2841 is a PWM DC/DC buck (step-down) regulator.

User's Guide
SNVA356C – March 2009 – Revised April 2013
AN-1876 LM2841 Evaluation Board
1 Introduction
The LM2841 is a PWM DC/DC buck (step-down) regulator. With a wide input range from 4.5V-42V, it is
suitable for a wide range of applications from automotive to power conditioning from unregulated sources.
The LM2841 evaluation board is designed to provide the design engineer with a fully functional power
converter based on the buck topology to evaluate the LM2841 series of buck regulators. The evaluation
board comes populated with the LM2841YMK-ADJL but can easily be modified to accommodate any of
the LM2841 regulator ICs.
2 Features
• 4.5V to 42V Input Voltage Range
• 3.3V Output Voltage
• Up to 300 mA Output Current
• 89% Efficiency at 300 mA
• Switching Frequency of 1.25 MHz
• Frequency Foldback Current Limit of 550 mA
• Internal Compensation
3 Shutdown Operation
The evaluation board includes a 3 pin header and a jumper to select whether the device is on or off.
Placing the jumper in the "ON" position ties SHDN to VIN and enables the device. Placing the jumper in
the "OFF" position ties SHDN to GND and disables the device. The jumper may be removed and a logic
signal may be applied to the center pin to test startup and shutdown of the device.
4 Adjusting the Output Voltage
The output voltage can be changed from 3.3V to another voltage by adjusting the feedback resistors using
the following equation:
V_OUT = V_FB(1 + (R1/R2))
(1)
Where V_FB is 0.76V.
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SNVA356C – March 2009 – Revised April 2013
AN-1876 LM2841 Evaluation Board
1
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