Texas Instruments ADS1226IRGVRG4

Overview

ADS1226IRGVRG4 from Texas Instruments is a 24-bit delta-sigma analog-to-digital converter with dual differential input channels (AINP1/AINN1 and AINP2/AINN2), internal oscillator, and integrated temperature sensor. It delivers 4µV_RMS noise in High-Resolution mode (16SPS) and 15µV_RMS noise in High-Speed mode (100SPS), operating from 2.7V to 5.5V supplies and specified over –40°C to +105°C. It is used in precision portable instrumentation for high-accuracy thermocouple or RTD signal digitization.

For engineers reviewing the ADS1226IRGVRG4 datasheet, ADS1226IRGVRG4 pinout, ADS1226IRGVRG4 application, or ADS1226IRGVRG4 equivalent, key selection considerations include its two-channel MUX control via dedicated MUX pin, single-cycle settling behavior, ratiometric measurement support via VREFP/VREFN inputs, and buffer-enabled 1GΩ differential input impedance - all in a 4mm × 4mm QFN-16 (RGV) package.

Technical Context

The ADS1226IRGVRG4 implements a delta-sigma modulator with programmable gain-free architecture, using an internal 2.048MHz oscillator to drive conversion timing without external clocking. Its two-stage input multiplexer selects between AINP1/AINN1, AINP2/AINN2, or internal temperature sensor (via TEMPEN), with independent buffer enable (BUFEN) and mode selection (MODE) for speed/resolution trade-off.

Conversion is initiated by pulse-triggered START pin, and data is retrieved via 2-wire serial interface (DRDY/DOUT and SCLK) in binary two's complement format. The device supports self-calibration while START remains high, and features automatic shutdown after conversion completion to minimize power consumption.

Key Specifications

Pinout & Package

ADS1226IRGVRG4 is housed in a 4mm × 4mm QFN-16 package (RGV) with exposed thermal pad. Pin 1 is START; pins 5–8 are dedicated to analog channel selection (MUX, TEMPEN, MODE, AINP2); pin 12 is GND; pins 13–16 are VREFN, VREFP, AVDD, DVDD.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 24-bit delta-sigma ADC applications.

Compared with ADS1220IPWR and AD7124-4BRUZ, the ADS1226IRGVRG4 uniquely balances dual-channel hardware MUX, integrated CJC, ultra-low power, and minimal 2-wire interface - making it the only option that satisfies simultaneous thermocouple/RTD measurement in space-constrained portable instruments without external components.

Availability

ADS1226IRGVRG4 is available at Aetrix Electronics and suitable for portable medical equipment, industrial process control, and hand-held instrumentation requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for ADS1226IRGVRG4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision data converters and low-power design.

The ADS1226IRGVRG4 belongs to TI's high-resolution delta-sigma ADC product line, engineered specifically for portable and space-constrained measurement systems demanding 24-bit accuracy, dual-sensor support, and sub-1mW power consumption.

FAQ

What is the function of the MUX pin on the ADS1226IRGVRG4?

The MUX pin on the ADS1226IRGVRG4 is a digital input that selects between two differential analog input pairs: logic low connects AINP1/AINN1, and logic high connects AINP2/AINN2. This hardware-controlled multiplexing allows the ADS1226IRGVRG4 to alternate between two sensors without host processor intervention or external switching circuitry, preserving timing integrity and reducing firmware overhead in dual-sensor applications.

Does the ADS1226IRGVRG4 support ratiometric measurements?

Yes, the ADS1226IRGVRG4 supports true ratiometric measurements via its dedicated VREFP and VREFN pins. When the reference voltage is derived from the same source as the sensor excitation (e.g., a current source driving an RTD), supply and temperature drift cancel out in the final digitized result. This configuration is explicitly validated in the datasheet and enables stable, high-accuracy measurements without recalibration across operating conditions.

How does the internal temperature sensor in the ADS1226IRGVRG4 work?

The ADS1226IRGVRG4 integrates a calibrated silicon diode temperature sensor with a nominal output of 106mV at +25°C and a linear coefficient of 360µV/°C. Activation is controlled by the TEMPEN pin: when high, the MUX routes the sensor output to the ADC core instead of analog inputs. This enables direct cold-junction compensation in thermocouple systems without external components or software interpolation.

What is the purpose of the BUFEN pin on the ADS1226IRGVRG4?

The BUFEN pin on the ADS1226IRGVRG4 enables a chopper-stabilized input buffer that raises differential input impedance from 2MΩ to 1GΩ and eliminates capacitive loading effects on the signal source. When BUFEN is high, the buffer isolates high-impedance sensors (e.g., pH electrodes or thermistors) from the ADC's internal sampling capacitors, preventing measurement errors caused by source loading or settling delays.

Can the ADS1226IRGVRG4 perform self-calibration, and how is it triggered?

Yes, the ADS1226IRGVRG4 supports on-chip self-calibration for offset and gain errors. It is triggered by applying two additional SCLK pulses immediately after reading all 24 bits of conversion data - but only when the START pin is held high. Calibration completes automatically, and DRDY/DOUT goes low to signal readiness of new valid data, requiring no external reference or user intervention.