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Evaluation Board User Guide
UG-253
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
Evaluation Board for the AD7291
8-Channel, I
2
C, 12-Bit SAR ADC with Temperature Sensor
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.
Rev. A | Page 1 of 16
FEATURES
Full-featured evaluation board for the AD7291
Link options
On-board analog bias-up circuit
PC control in conjunction with system demonstration
platform (SDP)
PC software for control
EVALUATION BOARD DESCRIPTION
The EVA L-AD7291SDZ is a full-featured evaluation board,
designed to allow the user to easily evaluate all features of the
AD7291. The evaluation board can be controlled via the system
demonstration platform (SDP) connector (J1). The SDP board
allows the evaluation board to be controlled through the USB
port of a PC using the AD7291 evaluation software.
On-board components include the ADP1706 low dropout
CMOS linear regulator; the AD8022 high speed, low noise amp;
and the AD8066 high performance 145 MHz FastFET™ amp.
The evaluation board features analog bias-up circuitry. Bipolar
signals are input via the VIN SMB connector and are biased up
by the on-board bias-up buffer circuit. The biased up signal is
available at the BIASED_VIN2 SMB and can be applied to any
one of the eight VINx SMB connectors using an SMB-SMB
cable.
Various link options are described in the Evaluation Board
Hardware section. The Link Options section of this user guide
should be consulted when configuring the board for standalone
operation.
DEVICE DESCRIPTION
The AD7291 is a 12-bit, 8-channel successive approximation
ADC with an internal temperature sensor. The part operates
from a single 3.3 V power supply and features an I
2
C®-
compatible interface. Each AD7291 provides a 2-wire serial
interface compatible with I
2
C interfaces.
The AD7291 offers a programmable sequencer, which enables
the selection of a preprogrammable sequence of channels for
conversion. The device has an on-chip 2.5 V reference that
can be disabled to allow the use of an external reference.
The AD7291 includes a high accuracy band-gap temperature
sensor, which is monitored and digitized by the 12-bit ADC to
give a resolution of 0.25°C.
Complete specifications for the AD7291 are provided in the
AD7291 data sheet, available from Analog Devices, Inc., which
should be consulted in conjunction with this data sheet when
using the evaluation board.
FUNCTIONAL BLOCK DIAGRAM
AD7291
V
IN0
V
IN7
VDD
V0
V7
SCL
SDA
AS1
AS0
V
DRIVE
DGND VDRIVE EXT_VCC AGND–5V AGND +5V
VDRIVE
SDP
BOARD
VIN VBIASED
BIAS-UP
BATTERY
3.3V
REGULATOR
EVAL-AD7291SDZ
USB
CONNECTION
TO PC
09710-001
Figure 1.
Verzeichnis
