Quick Start Procedure - Linear Technology DC2172A Demo Manual

DEMO MANUAL DC2172A

Quick start proceDure

Demonstration circuit 2172A is easy to set up to evaluate
the performance of the LTC7138. Please refer to Figure 1
for proper measurement equipment setup and follow the
procedure below.
1) With power off, connect the input supply, load and
meters as shown in Figure 1. Preset the load to 0A and
V supply to 0V.
IN
2) Place the RUN pin jumper (JP3) in the ON position.
3) Set the output to 5V by placing the JP1 jumper in the
B position and the JP2 jumper in the A position.
4) Turn-on the V supply and increase to 12V. The 5V
IN
output should be 5V ±2% per the Performance Sum-
mary table.
5) Next, apply 400mA load to the output and re-measure
V .
OUT
6) Once the DC regulation is confirmed, observe the output
voltage ripple, load step response, efficiency and other
parameters for the 5V, 3.3V and 1.8V output settings.
2
Note 1. CAUTION: The maximum input voltage of the
DC2172A is 140V. Voltages of 140V or lower are high
enough to cause electric shock. Use great care when
testing this demo board.
Note 2. For a 5V output, the input voltage should be 6V
or more.
Note 3. When measuring the output or input voltage ripple,
do not use the long ground lead on the oscilloscope probe.
See Figure 2 for the proper scope probe technique. Short,
stiff leads need to be soldered to the (+) and (–) terminals
of an output capacitor. The probe's ground ring needs to
touch the (–) lead and the probe tip needs to touch the
(+) lead.
dc2172af