a
LC2MOS
Complete, 14-Bit Analog I/O System
AD7869
FEATURES
Complete 14-Bit l/O System, Comprising
14-Bit ADC with Track/Hold Amplifier
83 kHz Throughput Rate
14-Bit DAC with Output Amplifier
3.5 s Settling Time
On-Chip Voltage Reference
Operates from ؎5 V Supplies
Low Power—130 mW typ
Small 0.3" Wide DIP
APPLICATIONS
Digital Signal Processing
Speech Recognition and Synthesis
Spectrum Analysis
High Speed Modems
DSP Servo Control
FUNCTIONAL BLOCK DIAGRAM
VDD
RI DAC
R
LDAC
DAC
SERIAL
INTERFACE
RFS
RCLK
ADC SERIAL
INTERFACE
DR
Interfacing to both the DAC and ADC is serial, minimizing pin
count and giving a small 24-pin package size. Standard control
signals allow serial interfacing to most DSP machines.
Asynchronous ADC conversion control and DAC updating is
made possible with the CONVST and LDAC logic inputs.
The AD7869 operates from ± 5 V power supplies; the analog input/output range of the ADC/DAC is ± 3 V. The part is fully
specified for dynamic parameters such as signal-to-noise ratio
and harmonic distortion as well as traditional dc specifications.
The part is available in a 24-pin, 0.3 inch wide, plastic or hermetic dual-in-line package (DIP) and in a 28-pin, plastic SOIC
package.
RO DAC
RO ADC
R
CLOCK
CONVST
The AD7869 is a complete 14-bit I/O system containing a DAC
and an ADC. The ADC is a successive approximation type with
a track-and-hold amplifier, having a combined throughput rate
of 83 kHz. The DAC has an output buffer amplifier with a settling time of 4 µs to 14 bits. Temperature compensated 3 V buried Zener references provide precision references for the DAC
and ADC.
DAC 3V
REFERENCE
ADC 3V
REFERENCE
CONTROL
CLK
GENERAL DESCRIPTION
VOUT
14 - BIT
DAC
TFS
TCLK
DT
R
AD7869
DGND
R
14 - BIT
ADC
VIN
TRACK/HOLD
VSS
AGND
PRODUCT HIGHLIGHTS
1. Complete 14-Bit I/O System.
The AD7869 contains a 14-bit ADC with a track-and-hold
amplifier and a 14-bit DAC with output amplifier. Also in
cluded are separate on-chip voltage references for the DAC
and the ADC.
2. Dynamic Specifications for DSP Users.
In addition to traditional dc specifications, the AD7869 is
specified for ac parameters, including signal-to-noise ratio
and harmonic distortion. These parameters, along with important timing parameters, are tested on every device.
3. Small Package.
The AD7869 is available in a 24-pin DIP and a 28-pin SOIC
package.
REV. A
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
World Wide Web Site: http://www.analog.com
Fax: 617/326-8703
© Analog Devices, Inc., 1996
