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User's Guide
SNVA334A–April 2008–Revised April 2013
AN-1819 LM5118 Evaluation Board
1 Introduction
The LM5118 evaluation board is designed to provide the design engineer with a fully functional, Emulated
Current Mode Control, buck-boost power converter to evaluate the LM5118 controller IC. The evaluation
board provides a 12V output with 3A of output current capability. The evaluation board’s wide input
voltage range is from 75V to 5V, with operation down to 3V with some component changes. The
evaluation board operates at 300 kHz, a good compromise between conversion efficiency, tradeoffs
between buck and buck-boost mode requirements, and converter size. The board is constructed with FR4
material. This user's guide contains the evaluation board schematic and Bill-of-Materials (BOM).
Refer to the LM5118 quick start (SNVU065) and for more complete circuit and design information, see
Wide Voltage Range Buck-Boost Controller (SNVS566).
The performance of the evaluation board is:
• Input Range: 75V to less than 5V at full current
• Operation to 3V at reduced current and appropriate adjustments. Operation at full current to around 3V
is possible with current limit sense resistor, UVLO threshold, and corresponding C
ramp
adjustment.
Additional input capacitance may be required. See the LM5118 datasheet (SNVS566) and quick start
(SNVU065) for more details.
• Output Voltage: 12V
• Output Current: 0 to 3A
• Frequency of Operation: 300 kHz
• Board Size: 3.45 × 2.65 inches
• Load Regulation: 1%
• Line Regulation: .1%
• Over-Current Limiting
• Operation with VIN greater or less than Vout
2 Features
• Integrated high and low side driver
• Internal high voltage bias regulator
• Ultra-wide input voltage range: 5V to 75V
• Emulated current mode control
• Single inductor architecture
• VOUT operation below and above VIN
• Single resistor sets oscillator frequency
• Oscillator synchronization capability
• Programmable soft-start
• Ultra low (<10 µA) shutdown current
• Enable input
• Wide bandwidth error amplifier
• Adjustable output voltage 1.23V to 75V
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SNVA334A–April 2008–Revised April 2013 AN-1819 LM5118 Evaluation Board
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