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1 EVM Overview

1.1 Features

User's Guide

SLAU181 – July 2006

ADS7866EVM/ADS7867EVM/ADS7868EVM

This Users Guide describes the characteristics, operation, and use of the

ADS7866/ADS7867/ADS7868 12/10/8-bit, 200/240/280-KSPS, high-speed,

serial-interface analog-to-digital (A/D) converter evaluation (EVM) board. A complete

circuit description as well as schematic diagram and bill of materials is included.

Contents

1 EVM Overview ...................................................................................... 1

2 Introduction .......................................................................................... 2

3 Analog Interface .................................................................................... 2

4 Digital Interface ..................................................................................... 4

5 Power Supplies ..................................................................................... 5

6 Using the EVM ...................................................................................... 5

7 ADS786xEVM BOM ................................................................................ 6

8 ADS786xEVM LAYOUT ........................................................................... 8

9 ADS786xEVM Schematic ......................................................................... 9

10 Related Documentation from Texas Instruments ............................................. 10

List of Figures

1 Input Buffer Circuit .................................................................................. 3

2 Top - Layer 1 ........................................................................................ 8

3 Ground Plane - Layer 2 ............................................................................ 8

4 Power Plane - Layer 3 ............................................................................. 9

5 Bottom - Layer 4 .................................................................................... 9

List of Tables

1 Analog Input Connector ............................................................................ 2

2 Jumper Setting ...................................................................................... 4

3 Serial Control Connector P2 ...................................................................... 4

4 Power Supply Test Points ......................................................................... 5

5 Power Connector Pin Out ......................................................................... 5

6 ADS786xEVM Bill of Materials .................................................................... 6

• Full-featured evaluation module (EVM) for the ADS7866/ADS7867/ADS7868 12/10/8-bit,

200/240/280-KSPS, single-channel, high-speed serial interface A/D converter.

• On board signal conditioning

• On board reference

TMS320C5000, TMS320C6000, TMS320C2000 are trademarks of Texas Instruments.

eZdsp is a trademark of Spectrum Digital.

SLAU181 – July 2006 ADS7866EVM/ADS7867EVM/ADS7868EVM 1

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Summary of content (15 pages)

PAGE 1
User's Guide SLAU181 – July 2006 ADS7866EVM/ADS7867EVM/ADS7868EVM This Users Guide describes the characteristics, operation, and use of the ADS7866/ADS7867/ADS7868 12/10/8-bit, 200/240/280-KSPS, high-speed, serial-interface analog-to-digital (A/D) converter evaluation (EVM) board. A complete circuit description as well as schematic diagram and bill of materials is included. 1 2 3 4 5 6 7 8 9 10 Contents EVM Overview ......................................................................................
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www.ti.com Introduction 2 Introduction The ADS7866 is a 12-bit, 200-KSPS serial-interface, analog-to-digital converter (ADC). The ADS7867 is a 10-bit, 240-KSPS serial-interface A/D converter. The ADS7868 is a 8-bit, 280-KSPS analog to digital converter. The devices include a capacitor based SAR A/D converter with inherent sample and hold. The serial interface for each A/D converter is controlled by the two signals chip select and serial shift clock.
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www.ti.com Analog Interface The type of input capacitors used in the signal path can make a few decibels of difference in AC performance. The factory recommends using either polypropylene or C0G type capacitor in the input signal path. The polypropylene capacitor causes the least distortion of the input signal and has excellent long-term stability, but is bulky and expensive. The C0G ceramic is lower cost, comes in smaller packages, and performs well in many applications.
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www.ti.com Digital Interface Table 2. Jumper Setting (1) Reference Designator SJP1 SJP2 W1 W2 W3 W4 (1) (2) 4 Jumper Setting Description 1-2 2-3 Installed (2) Set negative supply of U2 to ground. Select negative supply of U2 to -VCC. Not Installed Set negative supply of U4 to ground. Not Installed Installed (2) Select negative supply of U4 to -VCC. Installed (2) Apply CS from P2.1 to the ADC Chip select pin Apply FS from P2.
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www.ti.com Power Supplies 5 Power Supplies The EVM accepts four power supplies. • A dual ±VS dc supply for the dual supply operational-amplifiers. Recommended ±5 VDC. • A single 2.7 to 5-V dc supply for U3, the ADC supply reference (2.5-V, REF3225). • A single 1.8 to 3.3-V dc supply for digital section of the board (output buffers U6). There are two ways to provide these voltages. 1. Wire in voltages at test points on the EVM. See Table 4. Table 4.
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www.ti.com ADS786xEVM BOM 6.2 As a Prototype Board As a prototype board, the buffer circuit consists of resistor pads for configuring the input as either inverting or noninverting configurations. The input circuit can be modified to accommodate user prototype needs, whether it be evaluating another amplifier or limiting noise for best performance. The analog, power, and digital connectors can be made to plug into a standard 0.
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www.ti.com ADS786xEVM BOM Table 6. ADS786xEVM Bill of Materials (continued) 19 1 2.2uF C17 TDK Corporation or Alternate C1608X5R1A225MT CAP CER 2.2UF 6.3V X5R 20% 0603 20 1 10nF C13 TDK Corporation or Alternate C1608C0G1H100D CAP CER 10PF 50V C0G 0603 21 4 10uF C22 C23 C24 C25 TDK Corporation or Alternate C2012X5R0J106M CAP CER 10UF 6.
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www.ti.com ADS786xEVM LAYOUT 8 ADS786xEVM LAYOUT This chapter contains the layout drawings for revision B of the ADS7866EVM, ADS7867EVM, and ADS7868EVM printed circuit board. Figure 2. Top - Layer 1 Figure 3.
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www.ti.com ADS786xEVM Schematic Figure 4. Power Plane - Layer 3 Figure 5.
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Revision History REV ECN Number Approved D D J1 P1 1 3 5 7 9 11 13 15 17 19 2 4 6 8 10 12 14 16 18 20 +IN EXT_REF W1 CS Analog Input P2 SCLK C FS TP1 +VA +VA TP2 J2 +VA +AVCC DGND +3.3VD 1 3 5 7 9 2 4 6 8 10 -VA -VA CS SCLK -VA B_SDO B_SDO 1 3 5 7 9 11 13 15 17 19 2 4 6 8 10 12 14 16 18 20 C Serial Control AGND +5VD Power Supply TP3 W2 +VDD +AVCC +AVCC TP4 Circuits B B ti A A 12500 TI Boulevard.
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1 2 3 4 5 6 Revision History REV R4 ECN Number Approved +VA NI U3 0.47uF +5VCC GND_F GND_S ENABLE C2 R6 OUT_F OUT_S IN D 1uF 6 5 4 0 7 1 2 3 C8 R12 R3 REF3225 5 D U2 3 NI 0 R9 6 2 1 OPA735 0 R1 4 NI R2 +IOVDD 2 NI 1 3 SJP1 W3 -VA TP15 R18 C4 1uF 10k +5VCC W4 R15 CS 100 C10 +VCC C14 NI NI R14 C1 1k NI C 1 C TP5 C13 10nF R13 2 10k C9 1uF 0 +IOVDD +VA U5 1 2 3 C3 3 R5 C17 2.
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www.ti.com Related Documentation from Texas Instruments 10 Related Documentation from Texas Instruments To obtain a copy of any of the following TI documents, call the Texas Instruments Literature Response Center at (800) 477-8924 or the Product Information Center (PIC) at (972) 644-5580. When ordering, please identify this booklet by its title and literature number. Updated documents can also be obtained through our website at www.ti.com.
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EVALUATION BOARD/KIT IMPORTANT NOTICE Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES ONLY and is not considered by TI to be a finished end-product fit for general consumer use. Persons handling the product(s) must have electronics training and observe good engineering practice standards.
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Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright © 2006, Texas Instruments Incorporated EVM WARNINGS AND RESTRICTIONS It is important to operate this EVM within the input voltage range of 2.35 V to 5.25 V and the output voltage range of 0.4 V and VDD - 0.2 V. Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.