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ADS8402/ADS8412EVM
User’s Guide
December 2003 Data Acquistion
SLAU126
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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. All products are sold subject to TI’s terms and conditions of sale supplied at the t
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EVM IMPORTANT NOTICE Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by TI to be fit for commercial use. As such, the goods being provided may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including product safety measures typically found in the end product
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EVM WARNINGS AND RESTRICTIONS It is important to operate this EVM within the input voltage range of ±6 V and the output voltage range of 0 V and 5.5 V. Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questions concerning the input range, please contact a TI field representative prior to connecting the input power. Applying loads outside of the specified output range may result in unintended operation and/or possible permanent
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Related Documentation From Texas Instruments Preface Read This First About This Manual This users guide describes the characteristics, operation, and use of the ADS8402/ADS8412 16-bit, high speed, parallel interface analog-to-digital converter evaluation board. A complete circuit description as well as a schematic diagram and bill of materials are included. How to Use This Manual This document contains the following chapters: Chapter 1 – EVM Overview Chapter 2 – Analog Interface Chapter 3
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Contents FCC Warning This equipment is intended for use in a laboratory test environment only. It gen- erates, uses, and can radiate radio frequency energy and has not been tested for compliance with the limits of computing devices pursuant to subpart J of part 15 of FCC rules, which are designed to provide reasonable protection against radio frequency interference. Operation of this equipment in other en- vironments may cause interference with radio communications, in which case the user at his
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Contents Contents 1 EVM Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 2 Analog Interface . . . . . .
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Contents Figures 1-1 Input Buffer Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 5-1 Top Layer—Layer 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 5-2 Ground Plane—Layer 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5 5-3 Power Plane—Layer 3 . . . . . . . . . . . . .
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Chapter 1 EVM Overview This chapter contains the features of the ADS8402/ADS8412. Topic Page 1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 EVM Overview 1-1
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Features 1.1 Features Full-featured evaluation board for the high-speed ADS8402 (1.25 MSPS) and the ADS8412 (2 MSPS) high speed, 16-bit, single channel, parallel interface SAR-type analog-to-digital converters. Onboard signal conditioning Onboard reference Input and output digital buffer Onboard decoding for stacking multiple EVMs 1.2 Introduction The ADS8402EVM and ADS8412EVM is a modular or stand alone EVM. It has the bare minimum circuitry to showcase the device under test and plug
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Chapter 2 Analog Interface The ADS8402/ADS8412EVM analog-to-digital converter has a unipolar differential input. A unipolar differential input is a differential signal (inverting and noninverting input is 180 degrees out of phase) that is level shifted such that the signals levels are always equal to or above zero volts. The peak-to-peak amplitude on each input pin can be as large as the reference voltage. See the respective product data sheet for more information. Topic Page 2.1 Signal Condit
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Signal Conditioning 2.1 Signal Conditioning The ADS8402/ADS8412EVM comes installed with the unity gain buffer (U2) wired for single-ended in to differential out configuration. The common-mode voltage is derived from a REF3040 reference IC and is adjustable using a potentiometer (R9). The common-mode voltage pin of the THS4503 is set to 2 V on the evaluation module. A single-ended input signal can be applied at pin connector P1 or via SMA connectors J2 (noninverting input). The buffer circuit can
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Reference Figure 2-1. Input Buffer Circuit 60 pF 1 kΩ +V CC 0.1 µF THS4503 1 µF 1 k Ω 25 Ω + V (+) IN I - V +2.048 V 6800 pF OCM 25 Ω + (-) IN - 1 µF 1 kΩ 0.1 µF -V CC 1 kΩ 60 pF 2.2 Reference The EVM allows users to select from three reference sources. The ADS8402/ADS8412EVM provides an onboard 4.096-V reference, U3. The EVM also has the provision for users to supply a reference voltage via connecter P1 pin 20. The user reference voltage and onboard reference voltages can be filtered by install
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2-4
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Chapter 3 Digital Interface The ADS8402/ADS8412 EVM is designed for easy interfacing to multiple platforms. Samtec part numbers SSW-110-22-F-D-VS-K and TSM-110-01-T-DV-P provide a convenient dual row header/socket combination at P2 and P3. Consult Samtec at www.samtec.com or 1-800-SAMTEC-9 for a variety of mating connector options. Table 3-1.Pinout for Parallel Control Connector P2 Connector.Pin Signal Description P2.1 DC_CS Daughter card board select pin P2.3 P2.5 P2.7 A0 Address line from pr
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Table 3-2.Jumper Settings for Decoder Outputs Jumper Settings Reference Reference Designator Designator Description Description 1-2 2-3 † Set A[2..0] = 0x1 to generate RD pulse Installed Not installed W2 W2 Set A[2..0] = 0x2 to generate RD pulse Not installed Installed † Set A[2..0] = 0x3 to generate CONVST pulse Installed Not installed W5 W5 Set A[2..0] = 0x4 to generate CONVST pulse Not installed Installed † Set A[2..0] = 0x5 to generate RESET pulse Installed Not installed W4 W4 Set A[2..0] =
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Chapter 4 Power Supply Requirements The EVM accepts four power supplies. A dual ±Vs dc supply for the dual supply op-amps. Recommend ±7 Vdc supply. A single +5-Vdc supply for the analog section of the board (A/D + Reference). A single +5-V or +3.3-Vdc supply for the digital section of the board (A/D + address decoder + buffers). There are two ways to provide these voltages. 1) Wire in the voltages at test points on the EVM. See Table 4-1. Table 4-1.Power Supply Test Points Test Point Sig
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4-2
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Chapter 5 Using the EVM The ADS8402/ADS8412EVM serves three functions: 1) As a reference design 2) As a prototype board 3) As a software test platform Topic Page 5.1 As a Reference Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 5.2 As a Prototype Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 5.3 As a Software Test Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 Usin
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As a Reference Board 5.1 As a Reference Board As a reference design, the ADS8402/ADS8412EVM contains the essential circuitry to showcase the analog-to-digital converter. This essential circuitry includes the input amplifier, reference circuit, and buffers. The EVM analog input circuit is optimized for 100-kHz sine wave. Therefore, users may need to adjust the resistor and capacitor values of the A/D input circuit. In ac-type applications where signal distortion is a concern, polypropylene capaci
