UG-466 Datasheet, PDF (3/12 Pages) Analog Devices – Evaluation Board for the ADP2384/ADP2386, 20 V, 4 A/6 A Synchronous Step-Down DC-to-DC Regulators

Evaluation Board User Guide
USING THE EVALUATION BOARD
POWERING UP
The ADP2384/ADP2386 evaluation board is supplied fully
assembled and tested. Before applying power to the evaluation
board, follow the procedures in this section.
Jumper J6 (Enable)
Use one of the following methods to enable or to disable the
regulator:
• To enable the regulator, short the middle pin of J6, EN,
to HIGH.
• To disable the regulator, short the middle pin of J6, EN,
to GND.
Input Power Source
If the input power source includes a current meter, use that meter
to monitor the input current. Connect the positive terminal
of the power source to J7 (VIN) of the evaluation board, and
the negative terminal of the power source to J14 (GND) of the
evaluation board.
If the power source does not include a current meter, connect a
current meter in series with the input source voltage. Connect the
positive lead (+) of the power source to the positive (+) ammeter
terminal, the negative lead (−) of the power source to J14
(GND), and the negative lead (−) of the ammeter to J7 (VIN).
Output Load
Before connecting the load, ensure that the board is turned off.
Connect an electronic load or resistor to set the load current.
Connect the positive terminal of the load to J10 (VOUT) of the
evaluation board and connect the negative terminal of the load to
J13 (GND).
Input and Output Voltmeter
Measure the input and output voltages using voltmeters. Make
sure that the voltmeters are connected to the appropriate terminals
of evaluation board and not to the load or power source. If the
voltmeters are not connected directly to the evaluation board,
the measured voltages are incorrect due to the voltage drop across
the leads and/or connections between the evaluation board, the
power source, and/or the load.
To measure the input voltage, connect the positive terminal of the
voltmeter to J8 (VIN_SENSE) and the negative terminal to J12
(GND_SENSE). Likewise, to measure the output voltage, con-
nect the positive terminal of the voltmeter to J9 (VOUT_SENSE)
and the negative terminal to J15 (GND_SENSE).
UG-466
TurningOn the Evaluation Board
When the power source and load are connected to the evaluation
board, it can be powered for operation.
Perform the following steps to turn on the board:
1. Ensure that the power source voltage is >4.5 V and <20 V.
2. Ensure that EN is high and monitor the output voltage.
3. Turn on the load, check that it is drawing the proper load
current, and verify that the output voltage maintains its
regulation.
MEASURING EVALUATION BOARD PERFORMANCE
Measuringthe SwitchingWaveform
To observe the switching waveform with an oscilloscope, place the
oscilloscope probe tip at Test Point J11 (SW) with the probe ground
at J5 (GND). Set the scope to dc with the appropriate voltage and
time divisions. The switching waveform limits should alternate
approximately between 0 V and the input voltage.
MeasuringLoad Regulation
Load regulation can be tested by observing the change in the
output voltage with increasing output load current. To minimize
the voltage drop, use short low resistance wires.
MeasuringLine Regulation
Vary the input voltage and examine the change in the output
voltage with a fixed output current.
Line Transient Response
Generate a step input voltage change and observe the behavior
of the output voltage using an oscilloscope.
Load Transient Response
Generate a load current transient at the output and observe the
output voltage response using an oscilloscope. Attach the current
probe to the wire between the output and the load to capture
the current transient waveform.
Measuring Efficiency
The efficiency, η, is measured by comparing the input power with
the output power.
η = ^{VOUT × I OUT}
V_IN × I _IN
Measure the input and output voltages as close as possible to the
input and output capacitors to reduce the effect of voltage drop.
MeasuringInductor Current
The inductor current can be measured by removing one end of
the inductor from its pad and connecting a current loop in series.
A current probe can be connected onto this wire.
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