Texas Instruments ADS122C04IRTET

Overview

ADS122C04IRTET from Texas Instruments is a 24-bit, delta-sigma analog-to-digital converter with integrated PGA, dual programmable current sources (10 µA to 1.5 mA), internal 2.048-V reference (5 ppm/°C drift), I²C interface, and precision temperature sensor (±0.5°C typical accuracy). It supports up to 2 kSPS, offers simultaneous 50/60-Hz rejection at 20 SPS, and targets thermocouple, RTD, and bridge sensor signal conditioning in industrial field transmitters.

For engineers reviewing the ADS122C04IRTET datasheet, ADS122C04IRTET pinout, ADS122C04IRTET application, or ADS122C04IRTET equivalent, this page delivers verified technical context, real-world design meaning for key specs, validated WQFN-16 pin functions, application-specific role definitions, and two confirmed alternative parts with documented functional and parametric differences.

Technical Context

The ADS122C04IRTET integrates a low-noise, programmable-gain amplifier (gain 1–128), flexible 4-channel analog multiplexer (supporting two differential or four single-ended inputs), and dual-matched excitation current sources - enabling direct ratiometric measurement of resistive sensors without external components. Its digital filter provides single-cycle settling and simultaneous 50/60-Hz line-noise rejection at 20 SPS.

It features an I²C-compatible interface supporting Standard-, Fast-, and Fast-Mode Plus (up to 1 Mbps), 16 configurable slave addresses via A0/A1 pins, and operates across –40°C to +125°C with AVDD/DVDD supply range 2.3 V to 5.5 V. Internal oscillator accuracy is ±1% (normal mode) and ±2% (turbo mode).

Key Specifications

Pinout & Package

ADS122C04IRTET is packaged in a 3.0-mm × 3.0-mm, 0.75-mm-thick WQFN-16 (RTE) package with exposed thermal pad connected to AVSS.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision ADC applications.

Compared with ADS122C04IRTET, ADS1220IPWR trades integrated CJC and I²C for marginally better noise performance and SPI compatibility, while AD7124-4BRUZ adds robust diagnostics at the cost of interface flexibility and on-chip temperature sensing - making ADS122C04IRTET uniquely balanced for compact, I²C-connected sensor nodes requiring autonomous cold-junction compensation.

Availability

ADS122C04IRTET is available at Aetrix Electronics and suitable for field transmitters, PLC analog input modules, and heat meter sensor front-ends requiring stable component supply, long-lifecycle availability, and guaranteed traceable sourcing.

Supply support for ADS122C04IRTET 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 acquisition and industrial signal conditioning.

The ADS122C04IRTET belongs to TI's high-precision delta-sigma ADC product line, designed specifically for cost-sensitive, space-constrained industrial sensor nodes requiring integrated signal conditioning, I²C connectivity, and autonomous cold-junction compensation.

FAQ

What is the maximum achievable effective resolution of the ADS122C04IRTET at 20 SPS?

The ADS122C04IRTET achieves up to 20 bits effective resolution at 20 SPS with simultaneous 50/60-Hz rejection. This is measured under typical conditions (AVDD = 3.3 V, PGA enabled, internal reference, normal mode) and reflects usable noise-free bits after digital filtering - sufficient for 0.01% full-scale accuracy in thermocouple and RTD applications. The 24-bit architecture ensures no missing codes across the entire range.

Does the ADS122C04IRTET support external reference voltage, and what is the valid input range?

Yes, the ADS122C04IRTET supports external reference via REFP and REFN pins. The valid differential reference voltage range is 0.75 V to 2.5 V (or AVDD – AVSS, whichever is smaller). Absolute voltages must satisfy V(REFN) ≥ AVSS – 0.1 V and V(REFP) ≤ AVDD + 0.1 V. Using an external reference maintains full 24-bit linearity but disables the internal 2.048-V reference and its 5 ppm/°C drift spec.

How does the ADS122C04IRTET handle cold-junction compensation for thermocouples?

The ADS122C04IRTET uses its integrated precision temperature sensor (±0.5°C typical accuracy from –40°C to +125°C) to measure the isothermal block temperature adjacent to the thermocouple terminals. Firmware applies standard NIST ITS-90 polynomials to compute CJC offset, which is then algebraically added to the raw thermocouple ADC result. No external sensor or calibration coefficients are needed - the entire CJC function is self-contained within the ADS122C04IRTET.

What are the I²C address configuration options for the ADS122C04IRTET?

The ADS122C04IRTET provides 16 unique I²C slave addresses via two hardware pins: A0 and A1. Each pin accepts logic high (DVDD) or low (DGND), yielding four combinations (00, 01, 10, 11); combined with three programmable address bits in the device configuration register, this expands to 16 total addresses (0x40–0x4F). This enables daisy-chaining multiple ADS122C04IRTET devices on a single I²C bus without address collision.

Can the ADS122C04IRTET operate with separate analog and digital supply voltages?

Yes, the ADS122C04IRTET supports independent analog (AVDD/AVSS) and digital (DVDD/DGND) supplies. AVDD may range from 2.3 V to 5.5 V, and DVDD from 2.3 V to 5.5 V - allowing AVDD = 5.0 V for sensor excitation while DVDD = 3.3 V for I²C compatibility. However, AVSS and DGND must be connected to the same ground plane to maintain signal integrity and avoid ground loops in mixed-signal PCB layouts.