Datasheet

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5.1.4 Oscilloscope
5.1.5 Recommended Wire Gauge
5.1.6 Other
5.2 Equipment Setup
5.2.1 Input Connections
5.2.2 Output Connections
5.2.3 Other Connections
Test Set Up
A digital or analog oscilloscope can be used to measure the ripple voltage on V
OUT
. The oscilloscope
should be set for 1 M Ω impedance, 20MHz Bandwidth, AC coupling, 1 µ s/division horizontal resolution,
10mV/division vertical resolution for taking output ripple measurements. Test points TP1 and TP3 can be
used to measure the output ripple voltage by placing the oscilloscope probe tip through TP1 and holding
the ground barrel TP3 as shown in Figure 4 . Using a leaded ground connection may induce additional
noise due to the large ground loop area.
V
IN
to J1
The connection between the source voltage, V
IN
and J1 of the EVM can carry as much as 5 Amps DC.
The recommended wire size is 1x AWG #16 per input connection, with the total length of wire less than 4
feet (2 feet input, 2 feet return).
J2 to LOAD (Power)
The power connection between J2 of the EVM and LOAD can carry as much as 20-A DC. The minimum
recommended wire size is 2x AWG #16, with the total length of wire less than 4 feet (2 feet output, 2 feet
return).
FAN
This evaluation module includes components that can get hot to the touch, because this EVM is not
enclosed to allow probing of circuit nodes, a small fan capable of 200–400 lfm is required to reduce
component surface temperatures to prevent user injury. The EVM should not be left unattended while
powered. The EVM should not be probed while the fan is not running.
Shown in Figure 3 is the basic test set up recommended to evaluate the TPS40180EVM.
Working at an ESD workstation, make sure 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.
Prior to connecting the DC input source, V
IN
, it is advisable to limit the source current from V
IN
to 10A
maximum. Make sure V
IN
is initially set to 0V and connected as shown in Figure 3 .
1. Connect LOAD to J2, set LOAD to constant current mode to sink 0A DC before V
IN
is applied.
2. Connect voltmeter, V2, across TP1 and TP3, as shown in Figure 3 .
1. Place Fan as shown in Figure 3 and turn on, making sure air is flowing across the EVM.
Using the TPS40180EVM, A 20A Stackable Single Phase Synchronous Buck Converter6 SLVU213 – May 2007
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