2-Channel, Software-Selectable, True
Bipolar Input, 1 MSPS, 12-Bit Plus Sign ADC
Data Sheet
Rev. B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibilityisassumedbyAnalogDevicesforitsuse,norforanyinfringementsofpatentsorother
rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
2005–2013 Analog Devices, Inc. All rights reserved.
FEATURES
12-bit plus sign SAR ADC
True bipolar input ranges
Software-selectable input ranges
±10 V, ±5 V, ±2.5 V, 0 V to +10 V
1 MSPS throughput rate
Two analog input channels with channel sequencer
Single-ended, true differential, and pseudo differential
analog input capability
High analog input impedance
Low power: 21 mW
Full power signal bandwidth: 22 MHz
Internal 2.5 V reference
High speed serial interface
Power-down modes
14-lead TSSOP package
i
CMOS process technology
FUNCTIONAL BLOCK DIAGRAM
04863-
001
VIN0
DOUT
SCLK
CS
DIN
VDRIVE
VIN1
VDD
REFIN/OUT
VCC
AGND
VSS
DGND
CONTROL LOGIC
AND REGISTERS
13-BIT
SUCCESSIVE
APPROXIMATION
ADC
T/H
2.5V
VREF
I/P
MUX
CHANNEL
SEQUENCER
AD7322
Figure 1.
GENERAL DESCRIPTION
Th
e AD73221 is a 2-channel, 12-bit plus sign, successive approx-
imation analog-to-digital converter (ADC) designed on the
iCMOS (industrial CMOS) process. iCMOS is a process
combining high voltage silicon with submicron CMOS and
complementary bipolar technologies. It enables the develop-
ment of a wide range of high performance analog ICs capable of
33 V operation in a footprint that no previous generation of high
voltage parts could achieve. Unlike analog ICs using conventional
CMOS processes, iCMOS components can accept bipolar input
signals while providing increased performance, dramatically
reduced power consumption, and reduced package size.
Th
e AD7322 can accept true bipolar analog input signals. The
AD7322 has four software-selectable input ranges, ±10 V, ±5 V,
±2.5 V, and 0 V to +10 V. Each analog input channel can be
independently programmed to one of the four input ranges.
The analog input channels on th
e AD7322 can be programmed
to be single-ended, true differential, or pseudo differential.
The ADC contains a 2.5 V internal reference. The
AD7322 also
allows for external reference operation. If a 3 V reference is
applied to the REFIN/OUT pin, the
AD7322 can accept a true
bipolar ±12 V analog input. Minimum ±12 V VDD and VSS
supplies are required for the ±12 V input range. The ADC has a
high speed serial interface that can operate at throughput rates
up to 1 MSPS.
PRODUCT HIGHLIGHTS
1. The
AD7322 can accept true bipolar analog input signals,
±10 V, ±5 V, and ±2.5 V, and 0 V to +10 V unipolar signals.
2. The two analog inputs can be configured as two single-
ended inputs, one true differential input, or one pseudo
differential input.
3. 1 MSPS serial interface. SPI-/QSPI-/DSP-/MICROWIRE-
compatible interface.
4. Low power, 31 mW maximum, at 1 MSPS throughput rate.
5. Channel sequencer.
Table 1. Similar Devices
Device
Number
Throughput
Rate
Number of bits
Number of
Channels
1000 kSPS
12-bit plus sign
8
1000 kSPS
12-bit plus sign
8
500 kSPS
12-bit plus sign
8
1000 kSPS
12-bit plus sign
4
500 kSPS
12-bit plus sign
4
500 kSPS
12-bit plus sign
2
1
Protected by U.S. Patent No. 6,731,232.