4-Channel, Software-Selectable, True
Bipolar Input, 12-Bit Plus Sign ADC
AD7324
FUNCTIONAL BLOCK DIAGRAM
FEATURES
V
REFIN/OUT
V
12-bit plus sign SAR ADC
DD
CC
True bipolar input ranges
AD7324
Software-selectable input ranges
10 V, 5 V, 2.5 V, 0 V to +10 V
1 MSPS throughput rate
2.5V
VREF
V
V
V
V
0
1
2
3
IN
IN
IN
IN
13-BIT
I/P
MUX
SUCCESSIVE
APPROXIMATION
ADC
T/H
Four 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
DOUT
SCLK
CS
CONTROL LOGIC
AND REGISTERS
CHANNEL
SEQUENCER
DIN
High speed serial interface
Power-down modes
V
DRIVE
16-lead TSSOP package
iCMOS™ process technology
AGND
V
DGND
SS
Figure 1.
GENERAL DESCRIPTION
PRODUCT HIGHLIGHTS
The AD73241 is a 4-channel, 12-bit plus sign, successive
approximation 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 development of a wide range of high
performance analog ICs capable of 33 ꢁ 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
1. The AD7324 can accept true bipolar analog input signals,
±1ꢀ ꢁ, ±± ꢁ, ±2.± ꢁ, and ꢀ ꢁ to +1ꢀ ꢁ unipolar signals.
2. The four analog inputs can be configured as four single-
ended inputs, two true differential input pairs, two pseudo
differential inputs, or three pseudo differential inputs.
3. 1 MSPS serial interface. SPI®-/QSPI™-/DSP-/MICROWIRE™-
compatible interface.
4. Low power, 3ꢀ mW maximum, at 1 MSPS throughput rate.
consumption, and reduced package size.
±. Channel sequencer.
The AD7324 can accept true bipolar analog input signals. The
AD7324 has four software-selectable input ranges, ±1ꢀ ꢁ, ±± ꢁ,
±2.± ꢁ, and ꢀ ꢁ to +1ꢀ ꢁ. Each analog input channel can be
independently programmed to one of the four input ranges.
The analog input channels on the AD7324 can be programmed
to be single-ended, true differential, or pseudo differential.
Table 1. Similar Products Selection Table
Device
Number Rate
Throughput
Number of
Channels
Number of bits
12-bit plus sign
12-bit plus sign
12-bit plus sign
12-bit plus sign
12-bit plus sign
12-bit plus sign
AD7329
AD7328
AD7327
AD7323
AD7322
AD7321
250 kSPS
8
8
8
4
2
2
1000 kSPS
500 kSPS
500 kSPS
1000 kSPS
500 kSPS
The ADC contains a 2.± ꢁ internal reference. The AD7324 also
allows for external reference operation. If a 3 ꢁ reference is
applied to the REFIN/OUT pin, the AD7324 can accept a true
bipolar ±12 ꢁ analog input. Minimum ±12 ꢁ ꢁDD and ꢁSS
supplies are required for the ±12 ꢁ input range. The ADC has a
high speed serial interface that can operate at throughput rates
up to 1 MSPS.
1 Protected by U.S. Patent No. 6,731,232.
Rev. 0
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 that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registeredtrademarks arethe property of their respective owners.
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
©2005 Analog Devices, Inc. All rights reserved.