Quick Start Procedure - Analog Devices Linear Technology 2658A Demo Manual

DEMO MANUAL DC2658A

Quick start proceDure

Demonstration circuit 2658A is easy to set up to evalu-
ate the performance of the LT8643S. 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. Measure the output voltage ripple by
touching the probe tip directly across the output capaci-
tor. See Figure 5 for the proper scope technique. Figure 6
shows the output voltage ripple measured at the output
capacitor C9.
1. Place JP1 on BURST position.
2. With power off, connect the input power supply to
VIN_EMI and GND. If the input EMI filter is not desired,
connect the input power supply to V
3. With power off, connect the load from V
4. Turn on the power at the input.
NOTE: Make sure that the input voltage does not exceed
42V.
I
IN
+
–
–
POWER
V
SUPPLY
+ IN_EMI
4
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and GND.
IN
OUT
–
+
Figure 4. Proper Measurement Equipment Setup
5. Check for the proper output voltage (V
NOTE: If there is no output, temporarily disconnect the
load to make sure that the load is not set too high or is
shorted.
6. Once the proper output voltage is established, adjust
the load within the operating ranges and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
7. An external clock can be added to the SYNC terminal
when SYNC function is used (JP1 on the SYNC posi-
tion). Please make sure that R2 should be chose to set
the LT8643S switching frequency equal to or below the
lowest SYNC frequency. JP1 can also set LT8643S in
spread spectrum mode (JP1 on the SPREAD-SPEC-
TRUM position) or forced continuous mode (JP1 on
the FCM position).
to GND.
= 5V).
OUT
I
OUT
+
–
+
+
V
LOAD
OUT
–
–
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