2 LC MOS Complete 14-Bit, Sampling ADCs Data Sheet AD7871/AD7872 FEATURES FUNCTIONAL BLOCK DIAGRAMS C V V AGND REF REF OUT IN DD Complete monolithic 14-bit ADC 22 23 25 26 21 Twos complement coding TRACK- R AND-HOLD Parallel, byte, and serial digital interface R 80 dB SNR at 10 kHz input frequency COMP 57 ns data access time 3V 14-BIT REFERENCE DAC Low power: 50 mW typ 83 kSPS throughput rate 5 CLOCK CLK APPLICATIONS SAR + COUNTER Digital signal processing 28 14/8/CLK High speed modems CONTROL LOGIC CONVST 1 Speech recognition and synthesis PARALLEL AND SERIAL AD7871 Spectrum analysis INTERFACE DSP servo control 2 3 4 6 20 14 27 CS RD BUSY/INT DB13 DB0 DGND V SS GENERAL DESCRIPTION Figure 1. The AD7871/AD7872 are fast, complete, 14-bit analog-to- C V V V AGND REF REF OUT IN DD DD digital converters (ADC). They consist of a track-and-hold 12 11 13 14 9 16 amplifier, successive approximation ADC, 3 V buried Zener TRACK- R AND-HOLD reference, and versatile interface logic. The ADC features a self- contained, laser trimmed internal clock, so no external clock R COMP timing components are required. The on-chip clock may be 3V 14-BIT REFERENCE DAC overridden to synchronize ADC operation to the digital system for minimum noise. 3 CLK CLOCK The AD7871 offers a choice of three data output formats: a SAR + single, parallel, 14-bit word two 8-bit bytes or a 14-bit serial COUNTER data stream. The AD7872 is a serial output device only. The two CONTROL 1 CONTROL parts are capable of interfacing to all modern microprocessors LOGIC 2 CONVST SERIAL and digital signal processors. AD7872 INTERFACE The AD7871/AD7872 operate from 5 V power supplies, 4 5 6 8 15 accept bipolar input signals of 3 V and can convert full power SSTRB SCLK SDATA DGND V SS signals up to 41.5 kHz. Figure 2. In addition to the traditional dc accuracy specifications, the AD7871/AD7872 are also fully specified for dynamic 2 MOS Both devices are fabricated in Analog Devices, Inc., LC performance parameters including distortion and signal-to- mixed technology process. The AD7871 is available in 28-pin noise ratio. PDIP, PLCC, and CERDIP packages. The AD7872 is available in a 16-pin PDIP, CERDIP, and SOIC packages. PRODUCT HIGHLIGHTS 1. Complete 14-Bit ADC on a Chip. 2. Dynamic Specifications for DSP Users. 3. Low Power. Rev. F 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 2018 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com 12889-001 12889-002AD7871/AD7872 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Unipolar Offset And Full-Scale Adjustment .......................... 11 Applications ....................................................................................... 1 Timing and Control ................................................................... 12 General Description ......................................................................... 1 Data Output Formats ................................................................. 12 Functional Block Diagrams ............................................................. 1 Mode 1 Interface ......................................................................... 13 Product Highlights ........................................................................... 1 Mode 2 Interface ......................................................................... 14 Revision History ............................................................................... 2 Dynamic Specifications ............................................................. 15 Specif icat ions ..................................................................................... 3 Microprocessor Interface .......................................................... 16 Timing Characteristics ................................................................ 5 StandAlone Operation ............................................................... 17 Absolute Maximum Ratings ............................................................ 6 Applications Information .............................................................. 18 ESD Caution .................................................................................. 6 Layout Hints ................................................................................ 18 Pin Configuration and Function Descriptions ............................. 7 Noise ............................................................................................ 18 Theory of Operation ...................................................................... 10 Data Acquisition Board ............................................................. 18 Converter Details ........................................................................ 10 Interface Connections ............................................................... 19 Internal Reference ...................................................................... 10 Power Supply Connections ....................................................... 19 Track-And-Hold Amplifier ....................................................... 10 Shorting Plug Options ............................................................... 19 Analog Input ............................................................................... 10 Outline Dimensions ....................................................................... 22 Bipolar Offset Scale Adjustment .............................................. 11 Ordering Guide .......................................................................... 25 Unipolar Operation .................................................................... 11 REVISION HISTORY 11/2018Rev. E to Rev. F Change to Integral Nonlinearity, T Version Parameter, Table 1 ...... 3 Added Figure 6 Renumbered Sequentially .................................. 7 Added Figure 9 .................................................................................. 9 Changes to Ordering Guide ............................................................ 24 1/2015Rev. D to Rev. E Updated Format .................................................................. Universal Changed T Version Minimum SNR from 79 dB to 77 dB and Changed T Version Maximum INL from 1 LSB to 1.3 LSB ... 3 Deleted ADSP-2100 and TMS32020/C25 (Throughout) .......... 15 Deleted DSP56000 and ADSP-2101/ADSP-2102 (Throughout) ... 16 Updated Outline Dimensions ....................................................... 21 Changes to Ordering Guide .......................................................... 24 1/1997Rev. C to Rev. D Rev. F Page 2 of 25