Analog Devices EVAL-AD7723CB Quick Start Manual

FEATURES
Full-Featured Evaluation Board for the AD7723
EVAL-CONTROL BOARD Compatible
Stand Alone Capability
Versatile Analog Signal Conditioning Circuit
On-Board 2.5V Reference
Crystal or CMOS Clock Oscillator Sampling Clock
Serial or Parallel Conversion Data Interface
Various Linking Options
PC Software for Control and Data Analysis when
used with EVAL-CONTROL BOARD
Patch-work Area for User Expansion
INTRODUCTION
This Technical Note describes the evaluation board for the
AD7723 16-Bit, 1.2MSPS, CMOS, Sigma-Delta ADC.
The AD7723 evaluation board is designed to demonstrate
the AD7723's performance and to provide a flexible inter-
face for a variety of applications. Full data on the AD7723
is available in the AD7723 data sheet available from Analog
Devices and should be consulted in conjunction with this
Technical Note when using the Evaluation Board.
The AD7723 can operate with it's internal reference or the
on-board AD780 precision bandgap reference can be used
as an external reference. The analog input is conditioned
using two AD8047 op-amps and this circuit can be config-
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for
its use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Evaluation Board for 16-Bit, 1.2 MSPS
Figure. 1: FUNCTIONAL BLOCK DIAGRAM
DGND
VCC
-VS AGND+VS
AD 7 7 2 3
Parallel Interface
Serial Interface
16 Bit
16 Bit
Data Register Line Driver/Buffer
40 pin IDC Connector
CMOS, Sigma-Delta ADC
ured to drive the AD7723 with complimentary signals. The
EVAL-AD7723CB offers the flexibility of using an exter-
nal sampling clock, an on-board CMOS clock oscillator,
or the AD7723's crystal oscillator circuit. The board can be
configured for either parallel or serial mode operation. In
parallel mode, a 16-bit register, 74FCT162374, latches
the conversion results to a 40 pin IDC connector (P5). In
serial mode, the AD7723's serial interface signals are
buffered with a 74FCT162244 and are available from a 20-
pin header (P4).
The EVAL-AD7723CB is ideal for use as a stand-alone
unit or with the EVAL-CONTROL BOARD which is
available from Analog Devices under the order entry
"EVAL-CONTROL BOARD". Software is provided with
the evaluation board package to allow analysis of the ADC's
performance when using the EVAL-CONTROL BOARD.
A 96-pin DIN connector (P1) interfaces the control board
directly to the EVAL-AD7723CB.
The evaluation board uses extensive power and ground
planes to minimize high frequency noise interference from
the on-board clocks or any other source. The A
kept separate from the D
GND
AD7723. It is not recommended to connect the A
D planes elsewhere to avoid ground loop problems.
GND
Analog
Input
Signal
Conditioning
ADC
Sampling
Clock
20 pin header
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A. Tel:
617/329-4700
Fax: 617/326-8703
EVAL-AD7723CB
GND
plane and is joined under the
GND
Voltage
Reference
plane is
and