2-Channel, Software-Selectable, True

Bipolar Input, 1 MSPS, 12-Bit Plus Sign ADC

Data Sheet

AD7322

Rev. B

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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

DOUT

SCLK

CS

DIN

REFIN/OUT

AGND

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

The 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.

The 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 the 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

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

AD7329

1000 kSPS

12-bit plus sign

8

AD7328

1000 kSPS

12-bit plus sign

8

AD7327

500 kSPS

12-bit plus sign

8

AD7324

1000 kSPS

12-bit plus sign

4

AD7323

500 kSPS

12-bit plus sign

4

AD7321

500 kSPS

12-bit plus sign

2

1

Protected by U.S. Patent No. 6,731,232.