ANALOG DEVICES UG-188 Service Manual

Evaluation Board User Guide

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UG-188

Evaluation Board for the ADP2119/ADP2120 Step-Down Regulator

GENERAL DESCRIPTION

The ADP2119/ADP2120 are synchronous, step-down, dc-to-dc
regulators in a compact 3 mm × 3 mm LFCSP_WD package.

The ADP2119/ADP2120 evaluation boards provide an easy way
to evaluate the device. This user guide describes how to quickly
set up the board to collect performance data. Full details on the
ADP2119/ADP2120 are available in the ADP2119/ADP2120
data sheet, which is available from Analog Devices, Inc., and

ADP2119/ADP2120 EVALUATION BOARDS

should be consulted in conjunction with this user guide when
using the evaluation boards.

The ADP2119/ADP2120 run from input voltages of 2.3 V to 5.5 V
and require minimal external components to provide a high
efficiency solution with integrated power switch, synchronous
rectifier, and internal compensation.

09314-001

Figure 1. ADP2119 Evaluation Board Figure 2. ADP2120 Evaluation Board

09314-002

PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.

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UG-188 Evaluation Board User Guide

TABLE OF CONTENTS

General Description ......................................................................... 1

ADP2119/ADP2120 Evaluation Boards........................................ 1

Revision History ............................................................................... 2

Setting Up the Evaluation Board .................................................... 3

Powering up the Evaluation Board ............................................ 3

Measuring Evaluation Board Performance............................... 3

REVISION HISTORY

9/10—Revision 0: Initial Version

Typical Performance Characteristics ..............................................5

Evaluation Board Schematics and Artwork...................................6

Evaluation Board Layout ..................................................................7

Ordering Information.......................................................................8

Bill of Materials..............................................................................8

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Evaluation Board User Guide UG-188

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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 Tabl e 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
Low Disable V

J5
(SYNC/MODE)

High Force PWM (FPWM)
Low Enable PFM
External

clock
High Tracking function not used J7 (TRK)
External

voltage

Synchronize to the external clock

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

OUT

OUT

J3 (EN)

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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.

IV

OUTOUT

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 con­nected 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-

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IV

ININ