Evaluation Board User Guide
UG-188
Rev. 0 | Page 3 of 8
SETTING UP THE EVALUATION BOARD
POWERING UP THE EVALUATION BOARD
The
ADP2119
/
ADP2120
evaluation boards are fully assembled
and tested. Before applying power to the evaluation boards,
follow the setup procedures in this section.
Jumper Settings
Refer to Table 1 for selecting the jumper positions.
Before selecting the jumper positions, make sure that the enable
input, EN, is high.
Table 1. Jumper Settings
Jumper States
Function
High Enable
V
OUT
J3 (EN)
Low Disable
V
OUT
High
Force PWM (FPWM)
Low
Enable PFM
J5
(SYNC/MODE)
External
clock
Synchronize to the external clock
High
Tracking function not used
J7 (TRK)
External
voltage
Tracking with the external
voltage
Input Power Source Connection
Before connecting the power source to the ADP2119/ADP2120
evaluation boards, make sure that they are 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 VIN
terminal (J1) on the evaluation boards, and the negative
terminal of the power source to the GND terminal (J2) of the
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 terminal of the power source to the ammeter
positive terminal (+), the negative terminal of the power source
to the GND terminal (J2) on the evaluation board, and the
negative terminal (−) of the ammeter to the VIN terminal (J1)
on the board.
Output Load Connection
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 VOUT terminal
(J4) and negative (−) load connection to the GND terminal (J6).
If an ammeter is used, connect it in series with the load;
connect the positive (+) ammeter terminal to the evaluation
board VOUT terminal (J4), the negative (−) ammeter terminal
to the positive (+) load terminal, and the negative (−) load
terminal to the evaluation board GND terminal (J6).
Input and Output Voltmeter Connections
Measure the input and output voltages with voltmeters. Make
sure that the voltmeters are connected to the appropriate test
points on the board. If the voltmeters are not connected to the
right test point, the measured voltages may be incorrect due to
the voltage drop across the leads and/or connections between
the boards, the power source, and/or load.
Connect the positive (+) terminal of the input voltage
measuring voltmeter to Test Point T2 and the negative (−)
terminal to Test Point T1.
Connect the positive (+) terminal of the output voltage
measuring voltmeter to Test Point T4 and the negative (−)
terminal to Test Point T5.
Power On the Evaluation Board
When the power source and load are connected to the ADP2119/
ADP2120 evaluation board, it can be powered up for operation.
If the input power source is above 2.3 V, the output voltage rises
to 1.2 V as the default setting.
MEASURING EVALUATION BOARD
PERFORMANCE
Measuring the Switching Waveform
To observe the switching waveform with an oscilloscope,
place the oscilloscope probe tip at Test Point T6 with the
probe ground connected to GND. Set the oscilloscope to a
dc coupling, 2 V/division, and 1 μs/division time base. The
switching waveform should alternate between 0 V and
approximately the input voltage.
Measuring Load Regulation
Load regulation should be tested by increasing the load at the
output and measuring the output voltage between the T4 and
T5 test points.
Measuring Line Regulation
Vary the input voltage and measure the output voltage at a fixed
output current. Input voltage can be measured between T2 and
T1. The output voltage is measured between T4 and T5.
Measuring Efficiency
The efficiency, η, is measured by comparing the input power
with the output power.
IN
IN
OUT
OUT
I
V
I
V
η
×
×
=
Measuring Inductor Current
The inductor current can be measured by removing one end of
the inductor from the pad on the board and using a wire con-
nected between the pad and the inductor. Then, a current probe
can be used to measure the inductor current.
Measuring Output Voltage Ripple
To observe the output voltage ripple, place an oscilloscope
probe across the output capacitor (C4) with the probe ground
lead placed at the negative (−) capacitor terminal and the probe
tip placed at the positive (+) capacitor terminal. Set the oscillo-
