Analog Devices ADP2381 Evaluation Board ADP2381-EVALZ ADP2381-EVALZ Hoja De Datos
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ADP2381-EVALZ
Evaluation Board User Guide
UG-504
Rev. 0 | Page 3 of 12
USING THE EVALUATION BOARD
POWERING UP
evaluation board is supplied fully
assembled and tested. Before applying power to the evaluation
board, follow the procedures in this section.
board, follow the procedures in this section.
Jumper J12 (EN/SS)
Use one of the following methods to enable or disable the
regulator:
• To enable the regulator, leave Jumper J12 open.
• To disable the regulator, short Jumper J12.
regulator:
• To enable the regulator, leave Jumper J12 open.
• To disable the regulator, short Jumper J12.
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 J5 (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 J5 (VIN).
to monitor the input current. Connect the positive terminal of
the power source to J5 (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 J5 (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 J6 (VOUT) of the
evaluation board and connect the negative terminal of the load to
J13 (GND).
Connect an electronic load or resistor to set the load current.
Connect the positive terminal of the load to J6 (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. Ensure
that the voltmeters are connected to the appropriate terminals of
the 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 J7 (VIN_SENSE) and the negative terminal to J11
(GND_SENSE). Likewise, to measure the output voltage, connect
the positive terminal of the voltmeter to J8 (VOUT_SENSE) and
the negative terminal to J10 (GND_SENSE).
that the voltmeters are connected to the appropriate terminals of
the 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 J7 (VIN_SENSE) and the negative terminal to J11
(GND_SENSE). Likewise, to measure the output voltage, connect
the positive terminal of the voltmeter to J8 (VOUT_SENSE) and
the negative terminal to J10 (GND_SENSE).
Turning On 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 J12 (EN/SS) is open.
3. Turn on the load, ensure that it is drawing the proper load
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 J12 (EN/SS) is open.
3. Turn on the load, ensure that it is drawing the proper load
current, and verify that the output voltage maintains its
regulation.
regulation.
MEASURING EVALUATION BOARD PERFORMANCE
Measuring the Switching Waveform
To observe the switching waveform with an oscilloscope, place the
oscilloscope probe tip at Test Point J4 (SW) with the probe ground
at J16 (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.
oscilloscope probe tip at Test Point J4 (SW) with the probe ground
at J16 (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.
Measuring Load 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.
output voltage with increasing output load current. To minimize
the voltage drop, use short, low resistance wires.
Measuring Line Regulation
Vary the input voltage and examine the change in the output
voltage with a fixed output current.
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.
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.
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.
the output power.
IN
IN
OUT
OUT
I
V
I
V
η
×
×
=
Measure the input and output voltages as close as possible to the
input and output capacitors to reduce the effect of voltage drop.
input and output capacitors to reduce the effect of voltage drop.
Measuring Inductor 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.
the inductor from its pad and connecting a current loop in series.
A current probe can be connected onto this wire.
Measuring Output Voltage Ripple
To observe the output voltage ripple, place the oscilloscope probe
across the output capacitor with the probe ground lead connected
to the negative (−) capacitor terminal and the probe tip placed at
the positive (+) capacitor terminal. Set the oscilloscope to ac,
10 mV/division, 2 µs/division time base, and 20 MHz bandwidth.
across the output capacitor with the probe ground lead connected
to the negative (−) capacitor terminal and the probe tip placed at
the positive (+) capacitor terminal. Set the oscilloscope to ac,
10 mV/division, 2 µs/division time base, and 20 MHz bandwidth.