2
dc2458af
DEMO MANUAL DC2458A
QUICK START PROCEDURE
DC2458A is easy to set up to evaluate the performance
of the LT8608. Refer to Figure 4 for proper measurement
equipment setup and follow the procedure below:
NOTE: When measuring the input or output voltage ripple,
care must be taken to avoid a long ground lead on the
oscilloscope probe. See Figure 5 for the proper scope
technique.
1. Set an input power supply that is capable of 42V/1.5A.
Then turn off the supply.
2. With power off, connect the supply to the input
terminals V
IN
and GND.
3. Turn on the power at the input.
NOTE: Make sure that the input voltage never exceeds
42V.
4. Check for the proper output voltage of 5V. Turn off
the power at the input.
5. Once the proper output voltage is established, con-
nect a variable load capable of sinking 1.5A at 5V to
the output terminals V
OUT
and GND. Set the current
for 0A.
a. If efficiency measurements are desired, an am-
meter can be put in series with the output load in
order to measure the DC2458A’s output current.
b. A voltmeter can be placed across the output ter-
minals in order to get an accurate output voltage
measurement.
6. Turn on the power at the input.
NOTE: If there is no output, temporarily disconnect
the load to make sure that the load is not set too high.
7. Once the proper output voltage is established again,
adjust the load and/or input within the operating range
and observe the output voltage regulation, ripple
voltage, efficiency and other desired parameters.
8. An external clock can be added to the SYNC termi-
nal when SYNC function is used (JP1 on the SYNC
position). Please ensure that the chosen R
T
sets the
LT8608 switching frequency to equal or below the
lowest SYNC frequency. See the data sheet section,
Synchronization.
Figure 1. Efficiency vs Load Current at 2MHz Switching Frequency
I
OUT
(A)
0
EFFICIENCY (%)
100
95
85
75
90
80
55
60
65
70
50
0.5
DC2458a F01
1.5
1
12V INPUT
24V INPUT
