Texas Instruments ADS794xEVM, User Manual, Page: 4 / 31

Analog Interface
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4 SBAU194B – August 2011 – Revised September 2017
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ADS794xEVM and ADS794xEVM-PDK
2 Analog Interface
The ADS794xEVM is designed for easy interfacing to multiple analog sources. SMA connectors allow the
EVM to have input signals connected via coaxial cables. In addition, the Samtec connector provides a
convenient 10-pin, dual-row, header/socket combination at P2. This header/socket provides access to the
analog input pins of the ADS794x. Consult Samtec at
http://www.samtec.com or call 1-800-SAMTEC-9 for
a variety of mating connector options. All analog inputs are buffered by OPA836 high-speed operational
amplifiers in order to properly drive the ADS794x ADC inputs.
Use appropriate caution when handling these pins. Table 2 summarizes the pinout for analog interface P2.
Table 2. P2: Analog Interface Pinout (Samtec 10 x 2)
Pin Number Signal Description
P2.2 A0(+) / OPEN
CH0 positive differential input for ADS7945; open if
ADS7946 is installed
P2.4 A0(–)
CH0 negative differential input for ADS7945; single-
ended input for ADS7946
P2.10 A1(+) / OPEN
CH1 positive differential input for ADS7945; open if
ADS7946 is installed
P2.12 A1(–)
CH1 negative differential input for ADS7945; single-
ended input for ADS7946
P2.1-19 (odd) GND Analog ground connections (except J1.15)
P2.6 and P2.8 GND Analog ground connections
P2.14, P2.16, and P2.18 GND Analog ground connections
P2.15 V
REF
/4 or V
REF
/2
Unbuffered output. V
REF
/4 (J6 open) or V
REF
/2 (J6
closed)
P2.20 Ext V
REF
External reference voltage input
Table 3 lists the SMA analog inputs.
Table 3. SMA Analog Inputs
Pin Number Signal Description
J10 A0(+) / No SMA
CH0 positive differential input for ADS7945; no
SMA if ADS7946 is installed
J11 A0(–)
CH0 negative differential input for ADS7945; single-
ended input for ADS7946
J4 A1(+) / No SMA
CH1 positive differential input for ADS7945; no
SMA if ADS7946 is installed
J5 A1(–)
CH1 negative differential input for ADS7945; single-
ended input for ADS7946
As noted in Table 2 and Table 3 , there are different hardware configurations depending on the installed
converter. The ADS7945 uses two inputs per channel because of its fully differential inputs. The ADS7946
uses one input per channel for its pseudo-differential inputs.