Quick Start Procedure - Linear Technology DC1825A Demo Manual

DEMO MANUAL DC1825A

Quick start proceDure

The DC1825A is easy to set up to evaluate the performance
of the LT8300. Refer to Figure 1 for proper equipment
setup and follow the procedure below.
1. With power off, connect the input power supply to the
board through VIN (E1) and GND (E3) terminals. Connect
the load to the terminals VOUT+ (E4) and VOUT– (E2)
on the board.
2. Turn on the power at the input. Increase VIN slowly to
22V.
NOTE: Make sure that the input voltage is always within
spec. To operate the board with higher input/output
voltage, input capacitor, output capacitor and output
diode with higher voltage ratings are needed.
NOTE: To run overload tests on the demo board with
V higher than 40V, a RC snubber (200Ω, 150pF) or
IN
Schottky plus Zener clamp circuit is recommended to
make sure the voltage spike at the switching node is
always less than 150V.
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3. Check for the proper output voltages. The output should
be regulated at 5.0V (±5%).
NOTE: The LT8300 requires very small minimum load
to maintain good output voltage regulation. A Zener
diode is placed on the output to clamp the voltage to
~5.0V. This Zener is optional, and can be replaced with
a 5.1k resistor.
4. Once the proper output voltage is established, adjust
the input voltage and load current within the operating
range and observe the output voltage regulation, ripple
voltage, efficiency and other parameters.
NOTE: When measuring the input or output voltage
ripples, care must be taken to avoid a long ground
lead on the oscilloscope probe. Measure the input or
output voltage ripple by touching the probe tip directly
across the VIN (E1) and GND (E3), or VOUT+ (E4) and
VOUT– (E2) terminals. See Figure 2 for proper scope
probe technique.
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