Datasheet AD7938, AD7939 (Analog Devices) - 2

link to page 1 link to page 1 link to page 1 link to page 1 link to page 2 link to page 3 link to page 3 link to page 5 link to page 7 link to page 8 link to page 8 link to page 9 link to page 11 link to page 13 link to page 15 link to page 15 link to page 16 link to page 17 link to page 18 link to page 18 link to page 18 link to page 19 link to page 19 link to page 20 link to page 22 link to page 23 link to page 25 link to page 28 link to page 29 link to page 29 link to page 31 link to page 31 link to page 31 link to page 31 link to page 32 link to page 33
AD7938/AD7939 Data Sheet TABLE OF CONTENTS
Features .. 1 Circuit Information .. 18 Functional Block Diagram .. 1 Converter Operation .. 18 General Description ... 1 ADC Transfer Function ... 18 Product Highlights ... 1 Typical Connection Diagram ... 19 Revision History ... 2 Analog Input Structure .. 19 Specifications ... 3 Analog Inputs.. 20 AD7938 Specifications ... 3 Analog Input Selection .. 22 AD7939 Specifications ... 5 Reference ... 23 Timing Specifications .. 7 Parallel Interface ... 25 Absolute Maximum Ratings .. 8 Power Modes of Operation ... 28 ESD Caution .. 8 Power vs. Throughput Rate ... 29 Pin Configuration and Function Descriptions ... 9 Microprocessor Interfacing ... 29 Typical Performance Characteristics ... 11 Application Hints ... 31 Terminology .. 13 Grounding and Layout .. 31 On-Chip Registers .. 15 PCB Design Guidelines for Chip Scale Package .. 31 Control Register .. 15 Evaluating AD7938/AD7939 Performance .. 31 Sequencer Operation ... 16 Outline Dimensions ... 32 Shadow Register .. 17 Ordering Guide .. 33
REVISION HISTORY 10/2016—Rev. C to Rev. D
Updated Typical Performance Characteristics ... 13 Changed CP-32-2 to CP-32-7 .. Throughout Changes to Table 11 ... 16 Changes to Figure 2 .. 9 Changes to Analog Input Structure Section ... 18 Updated Outline Dimensions ... 32 Changes to Analog Inputs Section ... 19 Changes to Ordering Guide .. 33 Changes to Figure 17 .. 17 Changes to Figure 20 .. 18
10/2011—Rev. B to Rev. C
Changes to Figure 21 .. 19 Changes to SINAD Specification in Features Section ... 1 Changes to Figure 22 .. 19 Changes to AD7938 Specifications Section .. 3 Changes to Figure 24 .. 19 Updated Outline Dimensions ... 32 Changes to Figure 28 .. 21 Changes to Ordering Guide .. 33 Changes to Figure 29 .. 21 Changes to Figure 41 .. 28
2/2007—Rev. A to Rev. B
Changes to Figure 43 .. 28 Updated Format .. Universal Changes to Figure 44 .. 29 Changes to Sequencer Operation Section ... 16 Changes to Figure 45 .. 29 Updated Outline Dimensions ... 32 Changes to Figure 46 .. 29 Updated Outline Dimensions ... 31
7/2005—Rev. 0 to Rev. A
Changes to Ordering Guide .. 32 Changes to Specifications .. 3 Added Figure 3 .. 9
10/2004—Revision 0: Initial Version
Changes to Table 5 .. 10 Rev. D | Page 2 of 36 Document Outline FEATURES GENERAL DESCRIPTION PRODUCT HIGHLIGHTS REVISION HISTORY SPECIFICATIONS AD7938 SPECIFICATIONS AD7939 SPECIFICATIONS TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY ON-CHIP REGISTERS CONTROL REGISTER SEQUENCER OPERATION Writing to the Control Register to Program the Sequencer SHADOW REGISTER CIRCUIT INFORMATION CONVERTER OPERATION ADC TRANSFER FUNCTION TYPICAL CONNECTION DIAGRAM ANALOG INPUT STRUCTURE ANALOG INPUTS Single-Ended Mode Differential Mode Driving Differential Inputs Using an Op Amp Pair Pseudo Differential Mode ANALOG INPUT SELECTION Traditional Multichannel Operation (SEQ = SHDW = 0) Using the Sequencer: Programmable Sequence (SEQ = 0, SHDW = 1) Consecutive Sequence (SEQ = 1, SHDW = 1) REFERENCE Digital Inputs VDRIVE Input PARALLEL INTERFACE Reading Data from the AD7938/AD7939 Writing Data to the AD7938/AD7939 POWER MODES OF OPERATION Normal Mode (PM1 = PM0 = 0) Autoshutdown (PM1 = 0; PM0 = 1) Autostandby (PM1 = 1; PM0 = 0) Full Shutdown Mode (PM1 =1; PM0 = 1) POWER vs. THROUGHPUT RATE MICROPROCESSOR INTERFACING AD7938/AD7939 to ADSP-21xx Interface AD7938/AD7939 to ADSP-21065L Interface AD7938/AD7939 to TMS32020, TMS320C25, and TMS320C5x Interface AD7938/AD7939 to 80C186 Interface APPLICATION HINTS GROUNDING AND LAYOUT PCB DESIGN GUIDELINES FOR CHIP SCALE PACKAGE EVALUATING AD7938/AD7939 PERFORMANCE OUTLINE DIMENSIONS ORDERING GUIDE