Analog Devices ADP1872-EVALZ, Руководство пользователя

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ADP1872-EVALZ/ADP1873-EVALZ User Guide
UG-057
One
Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com
Evaluating the ADP1872 / ADP1873 PWM Buck Controllers
See the last page for an important warning and disclaimers.
Rev. A | Page 1 of 20
FEATURES
Wide power input voltage (V
IN
): 2.75 V to 20 V
Bias supply voltage (V
DD
) range: 2.75 V to 5.5 V
Available in 1.8 V fixed-output voltage
Available in 300 kHz, 600 kHz, and 1.0 MHz switching
frequency options
Available in power saving mode (PSM) for light loads
( ADP1873 only)
Starts into a precharged or preloaded output
APPLICATIONS
Perform basic evaluation board operations
Evaluate IC and application board performance
GENERAL DESCRIPTION
This document describes the evaluation board hardware for the
ADP1872 / ADP1873 PWM buck controllers. The evaluation boards
can be used to evaluate the ADP1872 or ADP1873 and application
circuits using these ICs without requiring any additional software.
The
ADP1872 / ADP1873 are versatile current-mode, synchronous
step-down controllers that provide superior transient response,
optimal stability, and current limit protection by using a constant
on-time, pseudo-fixed frequency with a programmable current-
sense gain, current-control scheme. The
ADP1873 is the power
saving mode (PSM) version of the device and is capable of pulse
skipping to maintain output regulation while achieving improved
system efficiency at light loads (see the
ADP1872 / ADP1873 data
sheet for more information). Both devices are available in a small,
10-lead MSOP package and can operate over the −40°C to +125°C
temperature range.
The
ADP1872 / ADP1873 evaluation boards employ a power input
voltage (V
IN
) that ranges between 2.75 V and 20 V and a bias supply
voltage (V
DD
) that ranges between 2.75 V and 5.5 V. Both inputs
can be tied together for application input voltage conditions equal
to or less than 5.5 V. The evaluation board is available in a fixed-
output voltage option (V
OUT
= 1.8 V), as well as in a 300 kHz,
600 kHz, or 1 MHz switching frequency (test trimmed in
production). The
ADP1872 / ADP1873 evaluation boards offer
an output accuracy of 2% over the full temperature range and
provide a high input voltage (V
IN
± 10%) and a full-scale load
current up to 15 A.
TYPICAL APPLICATIONS CIRCUIT
+
COMP/EN BST
FB DRVH
GND SW
VDD DRVL
PGND
VIN
C
C
C
VDD
C
VDD2
C
C2
R
C
R
TOP
R
BOT
V
OUT
V
DD
= 2.75V
TO 5.5V
Q1
Q2
R
RES
L
C
OUT
V
OUT
C
BST
LOAD
5A
C
IN
V
IN
= 2.75V TO 20V
ADP1872/
ADP1873
08548-
001
Figure 1.
08548-
100
Figure 2. ADP1872 Evaluation Board Configured
for 300 kHz Switching Frequency Operation
The ADP1872 / ADP1873 data sheet provides more information,
including details about how to modify the evaluation board while
maintaining system stability throughout the entire load current
range and, therefore, should be consulted in conjunction with
this user guide when using the evaluation boards.