Analog Interface; J1: Analog Interface Header - Texas Instruments ADS8638EVM-PDK User Manual

Analog Interface

2 Analog Interface
For maximum flexibility, the ADS8638EVM 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
options. Table 1 shows the pinout of the analog input connector, J1.
Pin Number
J1.2
J1.4
J1.6
J1.8
J1.10
J1.12
J1.14
J1.16
J1.1-19 (odd)
J1.15
J1.18
J1.20
The eight ADC analog inputs (four inputs for ADS8x34 devices) are available at the J1 header. All of these
inputs, with the exception of one, are routed directly from the J1 header to the ADC. The AIN2/AIN0
channel includes an
drive the ADC. The op amp is in unity gain, and includes a RC low-pass filter component before reaching
the ADC.
An external reference can be applied to the ADC via an external source using pin J1.20. This signal is
routed directly to JP2 where it can be jumped in to the VREFP line.
An OPA379 is located on the EVM to buffer the reference signal and output it on J1.15.
4
ADS8638EVM-PDK
www.samtec.com or call 1-800-SAMTEC-9 for a variety of mating connector
Table 1. J1: Analog Interface Header
Signal
AIN7 / NC
AIN6 / NC
AIN5 / AIN3
AIN4 / AIN2
AIN3 / AIN1
AIN2 / AIN0
AIN1 / NC
AIN0 / NC
GND
V
REFOUT
NC
Ext V
REF
OPA140 to help drive one of the analog input channels to show the proper way to
Copyright © 2011, Texas Instruments Incorporated
Description
ADC analog input (AIN7: ADS8x38, NC: ADS8x34)
ADC analog input (AIN6: ADS8x38, NC: ADS8x34)
ADC analog input (AIN5: ADS8x38, AIN3:
ADS8x34)
ADC analog input (AIN4: ADS8x38, AIN2:
ADS8x34)
ADC analog input (AIN3: ADS8x38, AIN1:
ADS8x34)
ADC analog input (AIN2: ADS8x38, AIN0:
ADS8x34)
ADC analog input (AIN1: ADS8x38, NC: ADS8x34)
ADC analog input (AIN0: ADS8x38, NC: ADS8x34)
Analog ground connections (except J1.15)
Buffered reference output
—
External reference voltage input
www.ti.com
SBAU192 – July 2011
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