Quick Start Procedure - Linear Technology LTM8045 Demo Manual

DEMO MANUAL DC1533A

QUICK START PROCEDURE

Demo circuit DC1533A is an easy way to evaluate the
performance of the LTM8045. Refer to Figure 1 for the
proper measurement equipment setup and Figure 2 for
the maximum output current versus input voltage, then
follow the procedure below:
NOTE: Do not hot-plug the V
ages. Hot-plugging a power supply through wire leads
to the demonstration circuit can cause the voltage on
the extremely low ESR ceramic input capacitor to ring to
twice its DC value. In order to protect the LTM8045, an
aluminum electrolytic capacitor with higher ESR is placed
at the input terminals. This may protect against some, but
not all, input transients due to a hot-plugged power supply.
See Application Note 88 for more details.
NOTE: When measuring the input or output voltage ripple,
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 V
2
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terminal at high input volt-
IN
IN
Figure 1. Proper Measurement Equipment Setup
V and GND terminals. See Figure 3 for proper scope
OUT
probe technique.
1. Place JP1 in the ON position.
2. Connect the power supply (with power off), load, and
meters as shown in Figure 1.
3. After all connections are made, turn on the input power
and verify that the output voltage is –5V.
NOTE: If the output voltage is too low, temporarily discon-
nect the load to make sure that the load is not set too high.
4. Once the proper output voltage is established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
NOTE: See the section that follows for instructions to
convert DC1533A to a 5V
or
SEPIC with a positive V
OUT
.
OUT
dc1533af