8-Channel, Software-Selectable, True Bipolar Input, 12-Bit Plus Sign ADC Data Sheet AD7328 FEATURES FUNCTIONAL BLOCK DIAGRAM V REFIN/OUT V DD CC 12-bit plus sign SAR ADC AD7328 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 V 1 VREF IN 13-BIT V 2 I/P IN SUCCESSIVE 1 MSPS 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 SCLK Low power: 21 mW CONTROL LOGIC AND REGISTERS CS CHANNEL Temperature indicator SEQUENCER DIN Full power signal bandwidth: 22 MHz V Internal 2.5 V reference DRIVE High speed serial interface AGND V DGND SS Power-down modes Figure 1. 20-lead TSSOP package iCMOS process technology GENERAL DESCRIPTION PRODUCT HIGHLIGHTS 1 The AD7328 is an 8-channel, 12-bit plus sign successive 1. The AD7328 can accept true bipolar analog input signals, approximation ADC designed on the iCMOS (industrial 10 V, 5 V, 2.5 V, and 0 V to +10 V unipolar signals. CMOS) process. iCMOS is a process combining high voltage 2. The eight analog inputs can be configured as eight single- silicon with submicron CMOS and complementary bipolar ended inputs, four true differential input pairs, four pseudo technologies. It enables the development of a wide range of high differential inputs, or seven pseudo differential inputs. performance analog ICs capable of 33 V operation in a footprint 3. 1 MSPS serial interface. SPI-/QSPI-/DSP-/MICROWIRE- that no previous generation of high voltage parts could achieve. compatible interface. Unlike analog ICs using conventional CMOS processes, iCMOS 4. Low power, 31 mW, at a maximum throughput rate of components can accept bipolar input signals while providing 1 MSPS. increased performance, dramatically reduced power consumption, 5. Channel sequencer. and reduced package size. Table 1. Similar Product Selection The AD7328 can accept true bipolar analog input signals. The Device Throughput Number of AD7328 has four software-selectable input ranges: 10 V, 5 V, Number Rate Number of Bits Channels 2.5 V, and 0 V to +10 V. Each analog input channel can be AD7329 1000 kSPS 12-bit plus sign 8 independently programmed to one of the four input ranges. The AD7327 500 kSPS 12-bit plus sign 8 analog input channels on the AD7328 can be programmed to be AD7324 1000 kSPS 12-bit plus sign 4 single-ended, true differential, or pseudo differential. AD7323 500 kSPS 12-bit plus sign 4 The ADC contains a 2.5 V internal reference. The AD7328 also AD7322 1000 kSPS 12-bit plus sign 2 allows for external reference operation. If a 3 V reference is applied AD7321 500 kSPS 12-bit plus sign 2 to the REFIN/OUT pin, the AD7328 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 1 Protected by U.S. Patent No. 6,731,232. serial interface that can operate at throughput rates up to 1 MSPS. Rev. C 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 20052014 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. 04852-001AD7328 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Sequence Register ....................................................................... 24 General Description ......................................................................... 1 Range Registers ........................................................................... 24 Functional Block Diagram .............................................................. 1 Sequencer Operation ..................................................................... 25 Product Highlights ........................................................................... 1 Reference ..................................................................................... 27 Revision History ............................................................................... 2 VDRIVE ............................................................................................ 27 Specifications ..................................................................................... 3 Temperature Indicator ............................................................... 27 Timing Specifications .................................................................. 6 Modes of Operation ....................................................................... 28 Absolute Maximum Ratings ............................................................ 7 Normal Mode (PM1 = PM0 = 0) ............................................. 28 ESD Caution .................................................................................. 7 Full Shutdown Mode (PM1 = PM0 = 1) ................................. 28 Pin Configuration and Function Descriptions ............................. 8 Autoshutdown Mode (PM1 = 1, PM0 = 0) ............................. 29 Typical Performance Characteristics ............................................. 9 Autostandby Mode (PM1 = 0, PM0 = 1) ................................ 29 Terminology .................................................................................... 13 Power vs. Throughput Rate ....................................................... 30 Theory of Operation ...................................................................... 15 Serial Interface ................................................................................ 31 Circuit Information .................................................................... 15 Microprocessor Interfacing ........................................................... 32 Converter Operation .................................................................. 15 AD7328 to ADSP-21xx .............................................................. 32 Analog Input Structure .............................................................. 16 AD7328 to ADSP-BF53x ........................................................... 32 Typical Connection Diagram ................................................... 18 Applications Information .............................................................. 33 Analog Input ............................................................................... 18 Layout and Grounding .............................................................. 33 Driver Amplifier Choice ............................................................ 20 Power Supply Configuration .................................................... 33 Registers ........................................................................................... 21 Outline Dimensions ....................................................................... 34 Addressing Registers .................................................................. 21 Ordering Guide .......................................................................... 34 Control Register .......................................................................... 22 REVISION HISTORY 1/14Rev. B to Rev. C Changes to Circuit Information Section and Table 6 ................ 15 6/06Rev. 0 to Rev. A Changes to Addressing Registers Section .................................... 21 Changes to Table 1 ............................................................................. 1 Changes to Power Supply Configuration Section ...................... 33 Changes to Specifications ................................................................. 3 Changes to Ordering Guide .......................................................... 34 Added Thermal Hysteresis to Terminology Section.................. 14 Change to Figure 42 ....................................................................... 20 2/10Rev. A to Rev. B Change to Control Register Section ............................................. 23 Change to Product Highlights Section .......................................... 1 Changes to DC Accuracy Parameter, Test Conditions/ 10/05Revision 0: Initial Version Comments, Table 2 ....................................................................... 3 Changes to Normal Mode (Operational) I CC and IDRIVE Parameter and to Power Dissipation Normal Mode Parameter, Table 2 ........................................................................ 5 Changes to Table 14 and Table 15 ................................................ 32 Added Power Supply Configuration Section and Figure 56 ..... 33 Changes to Ordering Guide .......................................................... 34 Rev. C Page 2 of 36