Texas Instruments ADS122U04IPW

Overview

ADS122U04 from Texas Instruments is a 24-bit, delta-sigma analog-to-digital converter with integrated UART interface, programmable gain amplifier (gain 1–128), dual matched excitation current sources (10 µA to 1.5 mA), internal 2.048-V reference (5 ppm/°C drift), and precision temperature sensor (±0.5°C accuracy). It supports up to 2 kSPS, delivers up to 20-bit effective resolution, and targets thermocouple and RTD signal conditioning in industrial sensor transmitters.

For engineers reviewing the ADS122U04 datasheet, ADS122U04 pinout, ADS122U04 application, or ADS122U04 equivalent, this page provides verified technical context, validated pin functions, confirmed UART timing and noise performance, real-world use cases for isolated sensor front-ends, and two rigorously cross-checked alternative ADCs with documented functional trade-offs.

Technical Context

The ADS122U04 integrates a low-noise PGA, 2-wire UART interface (up to 120 kBaud with auto-baud detection), and simultaneous 50/60-Hz rejection digital filter at 20 SPS. Its modulator operates at 256 kHz (normal) or 512 kHz (turbo), enabling single-cycle settling for fast system response.

It features four single-ended or two differential analog inputs, internal cold-junction compensation for thermocouples, and three GPIOs usable as DRDY, RESET, or general-purpose I/O - all operating across –40°C to +125°C with AVDD/DVDD supply range of 2.3 V to 5.5 V.

Key Specifications

Pinout & Package

ADS122U04 is available in a 3.0-mm × 3.0-mm WQFN-16 package (RTE) and 5.0-mm × 4.4-mm TSSOP-16 package (PW), both with exposed thermal pad connected to AVSS.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS122U04, ADS124S08 offers higher throughput and richer diagnostics but requires SPI isolation and external CJC, while AD7124-4 reduces power and adds flexibility in reference selection but lacks UART and integrated temperature sensing - making ADS122U04 uniquely optimized for isolated, thermocouple-centric, UART-connected systems.

Availability

ADS122U04 is available at Aetrix Electronics and suitable for industrial sensor transmitters, PLC analog input modules, and portable medical devices requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for ADS122U04 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 chain solutions.

The ADS122U04 belongs to TI's precision delta-sigma ADC product line, designed specifically for cost-sensitive, isolated sensor front-ends in industrial automation, process control, and portable instrumentation where UART simplifies digital interfacing.

FAQ

What is the maximum data rate supported by the ADS122U04?

The ADS122U04 supports up to 2000 samples per second (2 kSPS) in turbo mode. At this rate, the modulator frequency is 512 kHz, and the digital filter provides single-cycle settling. For applications requiring simultaneous 50-Hz and 60-Hz rejection, the optimal setting is 20 SPS - where the filter achieves >78 dB normal-mode rejection without external components. The ADS122U04 maintains 24-bit no-missing-codes resolution across all data rates.

Does the ADS122U04 include an internal temperature sensor, and how accurate is it?

Yes, the ADS122U04 integrates a precision on-die temperature sensor with 14-bit conversion resolution (0.03125°C step) and ±0.5°C accuracy over –40°C to +125°C. This sensor is explicitly used for cold-junction compensation in thermocouple applications and is factory-trimmed. Its accuracy is specified independently of supply voltage variation (0.25°C/V max), and it operates without external components - a key differentiator from discrete sensor + ADC solutions.

Can the ADS122U04 operate with an external reference, and what are the voltage limits?

Yes, the ADS122U04 supports external reference voltages applied differentially across REFP and REFN. The valid range is 0.75 V to 2.5 V, or up to AVDD–AVSS, whichever is smaller. When using an external reference, the internal 2.048-V reference is disabled, and analog supply current increases by 60 µA. External reference mode is commonly used when higher absolute accuracy or custom full-scale ranges are required beyond the internal reference's ±0.25% tolerance.

How does the UART interface of the ADS122U04 simplify isolated designs?

The ADS122U04's 2-wire UART interface (RX/TX, 8-N-1 format) reduces the number of digital isolation channels needed compared to SPI or I²C - requiring only two signal isolators instead of four or more. It supports baud rates up to 120 kBaud and includes auto-baud-rate detection, eliminating the need for precise clock synchronization across isolation barriers. This directly lowers bill-of-materials cost, PCB area, and power consumption in isolated sensor transmitters and PLC analog modules.

What are the supported package options for the ADS122U04, and are they pin-compatible?

The ADS122U04 is offered in two packages: 3.0-mm × 3.0-mm WQFN-16 (RTE) and 5.0-mm × 4.4-mm TSSOP-16 (PW). Both packages share identical pin numbering and function mapping per the datasheet - meaning pin 1 is RESET in both, pin 9 is AIN0, etc. However, they are not mechanically interchangeable due to differing footprint dimensions and thermal pad configuration. Layouts must be designed separately for each package, though firmware and schematic design remain fully compatible.