ADP2107-EVAL Analog Devices Inc, ADP2107-EVAL Datasheet - Page 3

• Manufacturer Part Number: ADP2107-EVAL
• Manufacturer: Analog Devices Inc

Specifications of ADP2107-EVAL

• Lead Free Status / Rohs Status: Not Compliant

USING THE EVALUATION BOARD
POWERING UP THE EVALUATION BOARD
The ADP2107 evaluation board is supplied fully assembled and
tested. Before applying power to the evaluation board, follow
the procedures in this section.
Jumper J1
Before turning on the ADP2107 evaluation board, make sure
that all the components are present, but Jumper J1 is removed.
Input Power Source
Before connecting the power source to the ADP2107 evaluation
board, make sure that it is turned off. 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
the V
of the power source to the GND terminal 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 ammeter positive
(+) connection, the negative lead (−) of the power source to the
GND terminal on the evaluation board, and the negative lead (−) of
the ammeter to the V
Output Load
Although the ADP2107 evaluation board can sustain the sudden
connection of the load, it is possible to damage the load if it is not
properly connected. Make sure that the board is turned off before
connecting the load. If the load includes an ammeter, or if the
current is not measured, connect the load directly to the
evaluation board with the positive (+) load connection to the
V
terminal. If an ammeter is used, connect it in series with the
load; that is, connect the positive (+) ammeter terminal to the
evaluation board V
terminal to the positive (+) load terminal, and the negative (−)
load terminal to the evaluation board GND terminal. Once the
load is connected, make sure that it is set to the proper current
before powering the ADP2107 evaluation board.
Input and Output Voltmeters
Measure the input and output voltages with voltmeters. Make
sure that the voltmeters are connected to the appropriate
evaluation board terminals, not 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.
Connect the input voltage measuring the voltmeter positive
terminal (+) to the evaluation board V
negative (−) terminal to the evaluation board GND terminal.
Connect the output voltage measuring voltmeter positive (+)
terminal to the evaluation board V
(−) terminal to the evaluation board GND terminal.
OUT
IN
terminal and the negative (−) load connection to the GND
terminal on the evaluation board and the negative terminal
OUT
IN
terminal on the board.
terminal, the negative (−) ammeter
OUT
terminal and the negative
IN
terminal and the
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Turning on the Evaluation Board
Once the power source and the load are connected to the
ADP2107 evaluation board, it can be powered up for operation.
Slowly increase the input power source voltage until the input
voltage exceeds the minimum input operating voltage of 2.7 V.
Insert Jumper J1, and check to see if the output voltage rises to
the regulated output voltage (1.8 V for the ADP2107-1.8-EVAL and
2.5 V for the ADP2107-EVAL). If the load is not already enabled,
enable the load, and check that it is drawing the proper current and
that the output voltage maintains voltage regulation.
MEASURING EVALUATION BOARD
PERFORMANCE
Measuring Output Voltage Ripple
To observe the output voltage ripple, place an oscilloscope
probe across the output capacitor (C3/C4) with the probe
ground lead at the negative (−) capacitor terminal and the probe
tip at the positive (+) capacitor terminal. Set the oscilloscope to ac,
20 mV/division, and 2 μs/division time base. In the PWM mode of
operation, the output voltage ripple is small (< 20 mV), but in PFM
mode, the output voltage ripple can be as large as 50 mV.
Measuring the Switching Waveform
To observe the switching waveform with an oscilloscope, place
the oscilloscope probe tip at the end of the inductor that is
connected to the LX pins with the probe ground at GND.
Set the scope to dc, 2 V/division, and 2 μs/division time base.
The switching waveform should alternate between 0 V and the
approximate input voltage.
Measuring Load Regulation
Load regulation must be tested by increasing the load at the output
and looking at the change in output voltage. To minimize voltage
drop, use short, low-resistance wires, especially for heavy loads.
Measuring Line Regulation
Vary the input voltage and examine the change in the output voltage.
Measuring Efficiency
The efficiency, η, is measured by comparing the input power
with the output power.
Measure the input and output voltages as close as possible to the
input and output capacitors to reduce the effect of IR drops.
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 with it. A current probe can then be used to measure the
current flowing through the current loop, as shown in Figure 2.
η
=
V
OUT
V
IN
×
×
I
I
OUT
IN
EVAL-ADP2107