Quick Start Procedure - Analog Devices Linear Technology DC2389A Demo Manual

Quick start proceDure

Demonstration circuit 2389A is easy to set up to evalu-
ate the performance of the LTM8073. Refer to Figure 5
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 oscil-
loscope probe. See Figure 6 for the proper scope technique.
1. Set an input power supply that is capable of 60V/3A.
Then turn off the supply.
2. With power off, connect the supply to the input terminals
V and GND.
EMI
3. Turn on the power at the input.
NOTE: Make sure that the input voltage never exceeds 60V.
4. Check for the proper output voltage of 5V. Turn off the
power at the input.
5. Once the proper output voltage is established, connect
a variable load capable of sinking 3A at 5V to the output
terminals V and GND. Set the current for 0A.
OUT
a. If efficiency measurements are desired, an ammeter
can be put in series with the output load in order to
measure the DC2389A's output current.
+
+
POWER
SUPPLY
–
–
+
V
IN
–
Figure 5. Proper Measurement Equipment Setup
DEMO MANUAL DC2389A
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 volt-
age, efficiency and other desired parameters.
8. An external clock can be added to the SYNC terminal
when SYNC function is used (JP1 on the SYNC position).
Please ensure that the chosen RT sets the LTM8073
switching frequency to equal or below the lowest SYNC
frequency. An external 2.9V to 4.2V DC voltage can
be applied to SYNC turret to enable low noise spread
spectrum function (JP1 on the SPREAD SPECTRUM
position). This DC voltage can be generated from V
with a appropriate voltage divider. See the data sheet
section, "Synchronization" for more information.
DC2389 F05
OUT
I
OUT
+
–
+
+
V
LOAD
OUT
–
–
dc2389af
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