Texas Instruments ADS7861EVM, User Manual

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EVM Overview
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1 EVM Overview
1.1 Features
ADS7861/8361/7863EVM:
• Full-featured evaluation board for the ADS7861, ADS8361, and ADS7863, dual, 500-kSPS,
12-bit/16-bit, serial output, 2+2 analog input, simultaneous sampling analog-to-digital converters
• Analog inputs can be configured as single-ended or differential
• Built-in reference
• High-speed serial interface
This manual covers the operation of the ADS7861EVM, ADS8361EVM, and the ADS7863EVM,
collectively identified as ADS7861/8361/7863EVM. Throughout this document, the abbreviation EVM and
the term evaluation module are synonymous with the ADS7861/8361/7863EVM. Unless otherwise
indicated, all references to device operation apply to all three devices.
1.2 Introduction
The ADS7861 operates from 5 V for AV
DD
and DV
DD
while the ADS8361 operates from 2.7 V to 3.6 V for
AV
DD
and DV
DD
. The ADS7863 operates from 2.7 V to 5.5 V for AV
DD
and DV
DD
. Each device is a
high-speed, low-power, 12-bit or 16-bit A/D converter (ADC).
The four fully-differential analog inputs are divided into two pairs (A and B). Each ADC accepts an analog
input voltage in the range of
–
VREF to +VREF (5 V
PP
), centered on the internal 2.5-V reference. The
device also accepts bipolar input ranges when a level shift circuit is used in the analog frontend circuitry.
Refer to Section 12 of the Design Guide, Op Amps for Everyone (literature number
SLOD006B ) for
information on various circuit applications.
2 Analog Interface
For maximum flexibility, the ADS7861/8361/7863EVM is designed for easy interfacing to multiple analog
sources. Samtec part numbers SSW
–
110
–
22
–
F
–
D
–
VS
–
K and TSM
–
110
–
01
–
T
–
DV
–
P provide a
convenient, 10-pin, dual row header/socket combination at J1. This header/socket provides access to the
analog input pins of the ADC. Consult Samtec at
http://www.samtec.com or call 1-800-SAMTEC-9 for a
variety of mating connector options. Table 1 summarizes the pinouts for analog interfaces J1.
Table 1. J1: Analog Interface Pinout
Pin Number Signal Description
J1.2 B1+ Noninverting input, channel B1
J1.4 B1 – Inverting input, channel B1
J1.6 B0+ Noninverting input, channel B0
J1.8 B0 – Inverting input, channel B0
J1.10 A1+ Noninverting input, channel A1
J1.12 A1 – Inverting input, channel A1
J1.14 A0+ Noninverting input, channel A0
J1.16 A0 – Inverting input, channel A0
Pins are unused and should be left open for
J1.18 Unused use with future amplifier and sensor input
modules.
External reference source input (2.5 V nom,
J1.20 REFIN
2.525 V max)
J1.1 to J1.19 (odd) AGND Analog ground connections
2 ADS7861/8361/7863EVM SLAU094A – October 2002 – Revised May 2011
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