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User's Guide
SNVA469B–May 2011–Revised April 2013
AN-2112 LM25117 Evaluation Board
1 Introduction
The LM25117 evaluation board provides the design engineer with a fully functional synchronous buck
converter based on Emulated Current Mode Control to evaluate the LM25117 controller IC. The evaluation
board provides 3.3V output with a 9A current capability in addition with average output current information.
The input voltage ranges from 6V to 36V.
2 Performance of the Evaluation Board
• Input Voltage Range: 6V to 36V
• Output Voltage: 3.3V
• Output Current: 9A
• Nominal Switching Frequency: 230 kHz
• Synchronous Buck Operation: Yes
• Diode Emulation Mode: Yes
• Hiccup Mode Overload Protection: Yes
• External VCC Sourcing: No
• Current Monitor Output: Yes
3 Powering and Loading Consideration
3.1 Proper Board Connection
When applying power to the LM25117 evaluation board certain precautions need to be followed. A
misconnection can damage the assembly.
The input connection is made to the J1 (VIN+) and J2 (VIN-) connectors. The load is connected to the J3
(VOUT+) and J4 (VOUT-). Be sure to choose the correct connector and wire size when attaching the
source power supply and the load. The average output current can be monitored at J5. Use RCA jack to
remotely sense the current monitor output. TP5 is directly connected to UVLO and can be used as an
input of the remote shutdown signal.
3.2 Source Power
The power supply and cabling must present low impedance to the evaluation board. Insufficient cabling or
a high impedance power supply will droop during power supply application with the evaluation board
inrush current. If large enough, this droop will cause a chattering condition upon power up. During power
down, this insufficient cabling or a high impedance power supply will overshoot, results in a non-
monotonic decay on the output.
An additional external bulk input capacitor may be required unless the output voltage droop/overshoot of
the source power supply is less than 0.5V.
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1
SNVA469B–May 2011–Revised April 2013 AN-2112 LM25117 Evaluation Board
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Verzeichnis
- ・ Blockdiagramm on Seite 7
- ・ Anwendungsbereich on Seite 12
- ・ Elektrische Spezifikation on Seite 5
