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500 kSPS, 8-Channel, Software-Selectable, True Bipolar Input, 12-Bit Plus Sign ADC AD7327
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 500 kSPS throughput rate Eight analog input channels with channel sequencer Single-ended, true differential, and pseudo differential analog input capability High analog input impedance Low power: 17 mW Temperature indicator Full power signal bandwidth: 22 MHz Internal 2.5 V reference High speed serial interface Power-down modes 20-lead TSSOP package iCMOS™ process technology
FUNCTIONAL BLOCK DIAGRAM
VDD REFIN/OUT VCC
AD7327
VIN0 VIN1 VIN2 VIN3 VIN4 VIN5 VIN6 VIN7 I/P MUX T/H 2.5V VREF
13-BIT SUCCESSIVE APPROXIMATION ADC
TEMPERATURE INDICATOR DOUT CONTROL LOGIC AND REGISTERS SCLK CS DIN VDRIVE AGND VSS DGND
05401-001
CHANNEL SEQUENCER
Figure 1.
GENERAL DESCRIPTION
The AD7327 is an 8-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 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 AD7327 can accept true bipolar analog input signals. The AD7327 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 AD7327 can be programmed to be single-ended, true differential, or pseudo differential. The ADC contains a 2.5 V internal reference. The AD7327 also allows for external reference operation. If a 3 V reference is applied to the REFIN/OUT pin, the AD7327 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 500 kSPS.
Rev. 0
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PRODUCT HIGHLIGHTS
1. 2. The AD7327 can accept true bipolar analog input signals, ±10 V, ±5 V, ±2.5 V, and 0 V to +10 V unipolar signals. The eight analog inputs can be configured as eight singleended inputs, four true differential inputs, four pseudo differential inputs, or seven pseudo differential inputs. 500 kSPS serial interface. SPI®-/QSPI™-/DSP-/MICROWIRE™compatible interface. Low power, 17 mW, at a maximum throughput rate of 500 kSPS. Channel sequencer.
Throughput Rate 1000 kSPS 1000 kSPS 1000 kSPS 500 kSPS 1000 kSPS 500 kSPS Number of Channels 8 8 4 4 2 2
3. 4. 5.
Table 1. Similar Devices
Device Number AD7329 AD7328 AD7324 AD7323 AD7322 AD7321 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
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Protected by U.S. Patent No. 6,731,232.
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AD7327 TABLE OF CONTENTS
Features .............................................................................................. 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Product Highlights ........................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Timing Specifications .................................................................. 7 Absolute Maximum Ratings............................................................ 8 ESD Caution.................................................................................. 8 Pin Configuration and Function Descriptions............................. 9 Typical Performance Characteristics ........................................... 10 Terminology .................................................................................... 14 Theory of Operation ....................................................................