TP7
TP10
Test Setup
5
Test Setup
5.1
Test Equipment
Voltage Source, VIN: The input voltage source VIN should be a 0-V to 6-V variable DC source capable of
supplying 5 A
DC
. Connect VIN to J2 as shown in
.
Multimeters:
•
V1: VIN at TP6 (VIN) and TP9 (GND), 0-V to 6-V voltmeter
•
V2: VOUT at TP7 (VOUT) and TP10 (GND)
•
A1: VIN input current, 0-A
DC
to 5-A
DC
Ammeter
Output Load: The output load should be an electronic constant resistance mode load capable of 0 A
DC
to
5 A
DC
at 1.5 V.
Oscilloscope: A digital or analog oscilloscope can be used to measure the output ripple. The oscilloscope
should be set for 1-M
Ω
impedance, 20-MHz bandwidth, AC coupling, 1-
µ
s/division horizontal resolution for
750-kHz switching frequency, 20-mV/division vertical resolution. Test points TP7 and TP10 can be used to
measure the output ripple voltage by placing the oscilloscope probe tip through TP7 and holding the
ground barrel on TP10 as shown in
. Using a leaded ground connection may induce additional
noise due to the large ground loop.
Figure 2. Tip and Barrel Measurement for VOUT Ripple
Fan: Some of the components in this EVM may approach temperatures of 55
º
C during operation. A small
fan capable of 200 LFM to 400 LFM is recommended to reduce component temperatures while the EVM is
operating. The EVM should not be probed while the fan is not running.
Recommended Wire Gauge:
•
VIN to J2: The recommended wire size is 1x AWG #14 per input connection, with the total length of
wire less than 4 feet (2 feet input, 2 feet return).
•
J3 to LOAD: The minimum recommended wire size is 1x AWG #14, with the total length of wire less
than 4 feet (2 feet output, 2 feet return)
5
SLUU671
–
December 2011
5-A Step-Down Regulator with Integrated Switcher
Copyright
©
2011, Texas Instruments Incorporated
