500 kSPS, 8-Channel, Software-Selectable, True Bipolar Input, 12-Bit Plus Sign ADC Data Sheet AD7327 FEATURES FUNCTIONAL BLOCK DIAGRAM V REFIN/OUT V DD CC 12-bit plus sign SAR ADC AD7327 True bipolar input ranges Software-selectable input ranges V 0 IN 2.5V 10 V, 5 V, 2.5 V, 0 V to +10 V VREF V 1 IN 13-BIT V 2 I/P IN SUCCESSIVE 500 kSPS throughput rate T/H MUX APPROXIMATION V 3 IN ADC 8 analog input channels with channel sequencer V 4 IN V 5 IN Single-ended, true differential, and pseudo differential V 6 TEMPERATURE IN INDICATOR analog input capability V 7 IN High analog input impedance DOUT CONTROL LOGIC SCLK Low power: 18 mW AND REGISTERS CS CHANNEL Temperature indicator SEQUENCER DIN Full power signal bandwidth: 22 MHz V DRIVE Internal 2.5 V reference High speed serial interface AGND V DGND SS Power-down modes Figure 1. 20-lead TSSOP package iCMOS process technology serial interface that can operate at throughput rates up to 500 kSPS. GENERAL DESCRIPTION 1 The AD7327 is an 8-channel, 12-bit plus sign successive PRODUCT HIGHLIGHTS approximation ADC designed on the iCMOS (industrial 1. The AD7327 can accept true bipolar analog input signals, CMOS) process. iCMOS is a process combining high voltage 10 V, 5 V, 2.5 V, and 0 V to +10 V unipolar signals. silicon with submicron CMOS and complementary bipolar 2. The eight analog inputs can be configured as eight single- technologies. It enables the development of a wide range of high ended inputs, four true differential inputs, four pseudo performance analog ICs capable of 33 V operation in a footprint differential inputs, or seven pseudo differential inputs. that no previous generation of high voltage parts could achieve. Unlike analog ICs using conventional CMOS processes, iCMOS 3. 500 kSPS serial interface. SPI-/QSPI-/DSP-/MICROWIRE- components can accept bipolar input signals while providing compatible interface. increased performance, dramatically reduced power 4. Low power, 18 mW, at a maximum throughput rate of consumption, and reduced package size. 500 kSPS. The AD7327 can accept true bipolar analog input signals. The 5. Channel sequencer. AD7327 has four software-selectable input ranges: 10 V, 5 V, Table 1. Similar Devices 2.5 V, and 0 V to +10 V. Each analog input channel can be independently programmed to one of the four input ranges. Device Throughput Number of Number Rate Number of bits Channels The analog input channels on the AD7327 can be programmed AD7329 1000 kSPS 12-bit plus sign 8 to be single-ended, true differential, or pseudo differential. AD7328 1000 kSPS 12-bit plus sign 8 The ADC contains a 2.5 V internal reference. The AD7327 also AD7324 1000 kSPS 12-bit plus sign 4 allows external reference operation. If a 3 V reference is applied AD7323 500 kSPS 12-bit plus sign 4 to the REFIN/OUT pin, the AD7327 can accept a true bipolar AD7322 1000 kSPS 12-bit plus sign 2 12 V analog input. Minimum 12 V VDD and VSS supplies are AD7321 500 kSPS 12-bit plus sign 2 required for the 12 V input range. The ADC has a high speed 1 Protected by U.S. Patent No. 6,731,232. Rev. B Document Feedback 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20062013 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 05401-001AD7327 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Sequence Register ....................................................................... 23 Functional Block Diagram .............................................................. 1 Range Registers ........................................................................... 24 General Description ......................................................................... 1 Sequencer Operation ..................................................................... 25 Product Highlights ........................................................................... 1 Reference ..................................................................................... 27 Revision History ............................................................................... 2 VDRIVE ............................................................................................ 27 Specifications ..................................................................................... 3 Temperature Indicator ............................................................... 27 Timing Specifications .................................................................. 7 Modes of Operation ....................................................................... 28 Absolute Maximum Ratings ............................................................ 8 Normal Mode .............................................................................. 28 ESD Caution .................................................................................. 8 Full Shutdown Mode .................................................................. 28 Pin Configuration and Function Descriptions ............................. 9 Autoshutdown Mode ................................................................. 29 Typical Performance Characteristics ........................................... 10 Autostandby Mode ..................................................................... 29 Terminology .................................................................................... 14 Power vs. Throughput Rate ....................................................... 30 Theory of Operation ...................................................................... 16 Serial Interface ................................................................................ 31 Circuit Information .................................................................... 16 Microprocessor Interfacing ........................................................... 32 Converter Operation .................................................................. 16 AD7327 to ADSP-21xx .............................................................. 32 Analog Input Structure .............................................................. 17 AD7327 to ADSP-BF53x ........................................................... 32 Typical Connection Diagram ................................................... 19 Application Hints ........................................................................... 33 Analog Input ............................................................................... 19 Layout and Grounding .............................................................. 33 Driver Amplifier Choice ............................................................ 21 Power Supply Configuration .................................................... 33 Registers ........................................................................................... 22 Outline Dimensions ....................................................................... 34 Addressing Registers .................................................................. 22 Ordering Guide .......................................................................... 34 Control Register .......................................................................... 22 REVISION HISTORY 12/13Rev. A to Rev. B Changes to Circuit Information Section and Table 6 ................ 16 Changes to Addressing Registers Section .................................... 22 Changes to Power Supply Configuration Section ...................... 33 Changes to Ordering Guide .......................................................... 34 1/10Rev. 0 to Rev. A Change to Features and Product Highlights Sections ................. 1 Changes to Table 2 ............................................................................ 5 Change to Endnote 1 in Table 4 ...................................................... 8 Added Power Supply Configuration Section, Figure 56, and Table 16 ............................................................................................ 33 1/06Revision 0: Initial Version Rev. B Page 2 of 36