National Semiconductor
Application Note 2051
Donald P. Jones
LM5050-2EVAL Evaluation
Board
November 1, 2010
Introduction
The LM5050-2 evaluation board is designed to demonstrate
the capabilities of the LM5050-2 OR-ing Diode Controller. It
is intended for evaluation of the functions of the LM5050-2.
One high side N-channel power MOSFET is used. The
LM5050-2 evaluation board schematic is shown in Figure 5.
The evaluation board is designed to highlight applications
with a small solution size. For more information about the
LM5050-2 functional and electrical characteristics, refer to the
LM5050-2 datasheet.
Operating Range
•
•
•
•
•
Minimum Input Voltage, 6V
Maximum Input Voltage, 50V
Output Current Range: 0A to 15A
Ambient Temperature Range 0°C to 50°C
Board Size 1.50 inches x 2.25 inches
30121312
To aid in the demonstration and evaluation of high-side OR-
ing diode controller solution based on the LM5050-2.
FIGURE 1. Forward Waveforms
The load current capability is limited at 15A by the ratings of
the terminals and the PCB copper area and weight. The PCB
layout has not been tested for currents above 15A, so this
should only be done with some degree of caution.
The maximum input voltage is limited by the breakdown volt-
age rating of both D1 and D2.
Typical evaluation board performance and characteristics
curves are shown in through . The PCB layout is shown in
and . Test points are provided for optional control and signal
monitoring.
Evaluation Board Start-Up
Before applying power to the LM5050-2 evaluation board, all
external connections should be verified. The external power
supply must be turned off and connected with proper polarity
to the VIN, VOUT, and GND terminals. Under basic evalua-
tion conditions the nPGD, VLOGIC, and Off test points are left
open.
30121313
The evaluation board will be in the normal operating mode
when power is applied. The Off terminal is used only when
there is a desire to disable normal operation and invoke the
MOSFET test comparator.
FIGURE 2. Reverse Waveforms
© 2010 National Semiconductor Corporation
301213
www.national.com