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4.2
Equipment Setup
Test Setup
J3 to LOAD1 (Power) — The power connection between J3 of HPA164 and LOAD1 can carry as much as
5 A dc. The minimum recommended wire size is 2x AWG 16, with the length of wire less than 4 feet (2
feet output, 2 feet return).
J3 to LOAD1 (Remote Sense) — If remote sense is used, the remote sense connection between J3 of
HPA164 and LOAD1 will carry less than 1 A dc. The minimum recommended wire size is AWG 22, with
the length of wire less and 4 feet (2 feet output, 2 feet return).
4.1.4
Oscilloscope
A 60-MHz or faster oscilloscope can be used to determine the ripple voltage on 3V3_OUT. The
oscilloscope should be set for 1-M
Ω
impedance, ac coupling, 1-
µ
s/division horizontal resolution,
20-mV/division vertical resolution for taking output ripple measurements. TP14 and TP15 can be used to
measure the output ripple voltage by placing the oscilloscope probe tip through TP14 and holding the
ground barrel to TP15 as shown in
Figure 3
. For a hands-free approach, the loop in TP15 can be cut and
opened to cradle the probe barrel. Using a leaded ground connection may induce additional noise due to
the large ground loop area. Connect a short wire from the barrel of the scope probe to TP15 as necessary
to reach between TP14 and TP15.
Shown in
Figure 3
is the basic test setup recommended to evaluate the TPS40200EVM-001. Note that
although the return for J1 and J3 are the same, the connections should remain separate as shown in
Figure 3
.
4.2.1
Procedure
1. Working at an ESD workstation, ensure that any wrist straps, bootstraps, or mats are connected
referencing the user to earth ground before power is applied to the EVM. Electrostatic smock and
safety glasses should also be worn.
2. Prior to connecting the dc-input source, V
12V_IN
, it is advisable to limit the source current from V
12V_IN
to
5 A maximum. Ensure that V
12V_IN
is initially set to 0 V and connected as shown in
Figure 2
.
3. Connect the ammeter A1 (0-A to 5-A range) between V
12V_IN
and J1 as shown in
Figure 3
.
4. Connect voltmeter V1 to TP1 and TP3 as shown in
Figure 3
.
5. Connect LOAD1 to J3 as shown in
Figure 1
. Set LOAD1 to constant current mode to sink 0 A dc
before V
12V_IN
is applied.
6. Connect voltmeter, V2 across J3 pin 3 and J3 pin 2 as shown in
Figure 3
.
7. Connect the oscilloscope probe to TP14 and TP15 as shown in
Figure 4
.
SLVU147A – February 2006 – Revised March 2006
Using the TPS40200
5
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