Test Equipment
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8
SLUUBN2 – March 2017
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Copyright © 2017, Texas Instruments Incorporated
TPS549B22EVM-847, 25-A Single Synchronous Step-Down Converter With
Full Differential Sense and PMBus™
6
Test Equipment
Voltage Source:
The input voltage source VIN must be a 0-V to 18-V variable DC source capable of
supplying at least 12 A
DC
.
Multimeters:
It is recommended to use two separate multimeters
Figure 2
. One meter is used to measure
V
IN
and one to measure V
OUT
.
Output Load:
A variable electronic load is recommended for testing
Figure 2
. It must be capable of 25 A
at voltages as low as 0.6 V.
Oscilloscope:
An oscilloscope is recommended for measuring output noise and ripple. Output ripple must
be measured using a tip-and-barrel method or better as shown in
Figure 3
.The scope must be adjusted to
20-MHz bandwidth, AC coupling at 50 mV/division, and must be set to 1-µs/division.
Fan:
During prolonged operation at high loads, it may be necessary to provide forced air cooling with a
small fan aimed at the EVM. Temperature of the devices on the EVM must be maintained below 105°C.
USB-to-GPIO Interface Adapter:
A communications adapter is required between the EVM and the host
computer. This EVM was designed to use TI's USB-to-GPIO adapter. Purchase this adapter at
http://www.ti.com/tool/usb-to-gpio
.
Recommended Wire Gauge:
The voltage drop in the load wires must be kept as low as possible in order
to keep the working voltage at the load within its operating range. Use the AWG 14 wire (2 wires parallel
for VOUT positive and 2 wires parallel for the VOUT negative) of no more than 1.98 feet between the EVM
and the load. This recommended wire gauge and length should achieve a voltage drop of no more than
0.2 V at the maximum 25-A load.
