Texas Instruments ADS1226IRGVT

Overview

ADS1226IRGVT 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 supports ratiometric measurements via external voltage reference. It is used in precision portable medical sensors requiring low-power, high-accuracy DC signal acquisition.

For engineers reviewing the ADS1226IRGVT datasheet, ADS1226IRGVT pinout, ADS1226IRGVT application, or ADS1226IRGVT equivalent, key selection criteria include its dual-channel MUX control, START-triggered single-cycle settling, buffer-enabled 1GΩ input impedance, and guaranteed –40°C to +105°C operation with <1µA shutdown current.

Technical Context

The ADS1226IRGVT implements a delta-sigma modulator with programmable gain-free architecture, using an internal 2.048MHz oscillator for timing. Its two-channel analog multiplexer is controlled by the MUX pin (Pin 5), selecting either AINP1/AINN1 or AINP2/AINN2 as the active differential pair before the input buffer stage.

Conversion control is synchronous and event-driven: a pulse on START (Pin 1) initiates sampling, DRDY/DOUT (Pin 3) asserts low upon completion, and data is clocked out MSB-first via SCLK (Pin 2). The MODE pin (Pin 7) selects between High-Speed (100SPS, 15µV_RMS) and High-Resolution (16SPS, 4µV_RMS) operating modes without reconfiguration overhead.

Key Specifications

Pinout & Package

ADS1226IRGVT is housed in a 4mm × 4mm QFN-16 package (RGV) with wettable flanks and exposed thermal pad. Pin 1 is marked by a dot; orientation follows standard top-view labeling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS1226IRGVT, ADS1220IPWR offers lower noise but sacrifices dual-input flexibility and embedded temperature sensing, while AD7124-4BRUZ adds channel count and PGA capability at the cost of 23× higher active power and loss of the simple 2-wire interface.

Availability

ADS1226IRGVT is available at Aetrix Electronics and suitable for portable medical equipment, industrial process transmitters, handheld instrumentation, and battery-powered sensor nodes requiring stable component supply across extended temperature ranges.

Supply support for ADS1226IRGVT 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 signal chains.

The ADS1226IRGVT belongs to TI's precision delta-sigma ADC product line, designed specifically for high-resolution, low-power, space-constrained measurement systems where simplicity, reliability, and guaranteed performance over –40°C to +105°C are mandatory.

FAQ

What is the function of the MUX pin on the ADS1226IRGVT?

The MUX pin (Pin 5) selects which differential analog input pair is routed to the ADC core: logic low connects AINP1/AINN1, and logic high connects AINP2/AINN2. This hardware-multiplexed switching occurs before the input buffer and enables dual-sensor monitoring without external analog switches or firmware-controlled reconfiguration delays. The ADS1226IRGVT does not support simultaneous sampling of both channels - only one pair is active per conversion cycle.

Does the ADS1226IRGVT require an external crystal or clock source?

No, the ADS1226IRGVT integrates a factory-trimmed 2.048MHz internal oscillator and operates autonomously without any external timing components. This eliminates crystal cost, PCB area, and frequency tolerance risks. The oscillator drives all internal timing functions including modulation, conversion control, and serial interface synchronization - confirmed in the Electrical Characteristics table and Figure 26 of the SBAS346C datasheet.

How does the temperature sensor in the ADS1226IRGVT work, and what accuracy can be expected?

The ADS1226IRGVT uses two on-die diodes (1× and 64× size/current ratio) whose forward-voltage difference changes linearly with temperature. With TEMPEN high, this delta-V is digitized as a 24-bit value. At +25°C, output is typically 106mV with 360µV/°C slope. Absolute accuracy depends on system calibration but repeatability is ±0.5°C over –40°C to +105°C. The ADS1226IRGVT datasheet specifies no initial offset error for the sensor path.

Can the ADS1226IRGVT perform continuous conversions, and how is this enabled?

Yes, the ADS1226IRGVT supports continuous conversion mode by holding the START pin high. In this state, a new conversion begins immediately after the previous one completes - no gap between samples. Data rate remains fixed at the selected MODE setting (16SPS or 100SPS). The ADS1226IRGVT automatically shuts down only when START is pulled low; otherwise, it remains active and ready for uninterrupted data streaming.

What is the purpose of the BUFEN pin, and when should it be enabled?

The BUFEN pin (Pin 4) enables a chopper-stabilized input buffer that raises differential input impedance from 2MΩ (buffer off) to 1GΩ (buffer on). Enable BUFEN when measuring high-impedance sources like pH electrodes, thermocouples, or unbuffered bridge sensors to prevent loading-induced gain error and drift. Disable BUFEN for low-impedance sources (<1kΩ) to reduce power consumption and avoid unnecessary noise contribution from the buffer stage.