Texas Instruments ADS1263EVM-PDK User Manual page 6

Analog Interface
3.1.1 ADS1263 Integrated Input Functions
Each ADS1263 analog input pin has multipurpose functionality to support a wide variety of device applications.
Table 3-1 summarizes the functions available for each ADC input pin.
Input Pin ADC Input
AIN0 Yes
AIN1 Yes
AIN2 Yes
AIN3 Yes
AIN4 Yes
AIN5 Yes
AIN6 Yes
AIN7 Yes
AIN8 Yes
AIN9 Yes
AINCOM Yes
3.1.1.1 ADC Inputs
The ADS1263 has a flexible input multiplexer with 11 analog inputs. Any input can connect to the positive input
and any input can connect to the negative input. The ADS1263 also includes an auxiliary, 24-bit ΔΣ ADC with
an independent flexible input multiplexer to all input pins. Configure the inputs to provide either single-ended or
differential input measurements.
3.1.1.2 IDAC Output
The ADS1263 provides dual-matched current sources (IDAC1 and IDAC2) for biasing of RTDs, thermistors, and
other resistive-biased sensors. The IDACs can be independently programmed and can be connected to any
analog input. Each IDAC output is programmable from 50 μA to 3000 μA. The ADC internal reference must be
enabled for IDAC operation.
3.1.1.3 VBIAS Output
For single-supply operation, the level-shift function (VBIAS) can offset the common input voltage on AINCOM to
a mid-supply voltage ([AVDD + AVSS] / 2).
3.1.1.4 External Reference
The ADS1263 can accept an external reference in addition to the internal and supply reference options. The
external reference inputs are shared with pins AIN0 through AIN5. ADC1 and ADC2 can share a reference
source, though an independent reference source can also be selected for ADC2.
3.1.1.5 Test DAC Output
An internal test DAC (TDAC) provides a known voltage to the ADC to diagnose the operation of the signal chain.
The positive and negative TDAC voltages are output on AIN6 (J3:7) and AIN7 (J3:8), respectively. Do not load
AIN6 and AIN7 when the test signals are enabled because the TDAC outputs are unbuffered.
3.1.1.6 GPIO
Eight inputs (AIN3 through AINCOM) are configurable as general-purpose input/outputs (GPIO). The GPIO
voltages are referenced to the analog power supply (AVDD and AVSS) and therefore must use 5-V logic. Use
the GPIOs to control external devices or to read external logic signals.
3.1.2 Analog Sensor Connections
The ADS1263 is designed to easily interface with many types of analog sensors including weigh scales, strain
gauge sensors, and analog temperature sensors. The following sections provide more detail for connecting
and measuring temperature sensors, including thermocouples (see
6 ADS1263EVM-PDK Evaluation Module
Table 3-1. ADS1263 Analog Input Pin Functions
IDAC Output VBIAS Output
Yes —
Yes —
Yes —
Yes —
Yes —
Yes —
Yes —
Yes —
Yes —
Yes —
Yes Yes
Copyright © 2023 Texas Instruments Incorporated
External VREF
Test DAC Output
Input
REF1 P —
REF1 N —
REF2 P —
REF2 N —
REF3 P —
REF3 N —
— Yes
— Yes
— —
— —
— —
Section 3.1.2.1), thermistors (see
SBAU206B – APRIL 2015 – REVISED MAY 2023
www.ti.com
GPIO
—
—
—
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
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