Texas Instruments ADS1257IRGWT

Overview

ADS1257IRGWT from Texas Instruments is a 24-bit delta-sigma analog-to-digital converter with integrated 4-channel multiplexer, programmable gain amplifier (PGA) up to 64×, 5-mm × 5-mm VQFN-20 package, and SPI-compatible serial interface. It delivers up to 23 bits noise-free resolution at 2.5 SPS and supports single-cycle settled conversions ≤1000 SPS for high-precision industrial sensor digitization.

For engineers reviewing the ADS1257IRGWT datasheet, ADS1257IRGWT pinout, ADS1257IRGWT application, or ADS1257IRGWT equivalent, key selection criteria include differential/single-ended input flexibility (2 diff or 3 SE), 50/60-Hz rejection capability, on-chip sensor break detection, dual general-purpose I/Os, and dual-supply operation (5 V AVDD, 1.8–3.6 V DVDD).

Technical Context

The ADS1257IRGWT implements a fourth-order delta-sigma modulator with programmable digital filter enabling data rates from 2.5 SPS to 30 kSPS. Its PGA supports seven discrete gain settings (1–64) and operates with or without an integrated high-impedance input buffer (≥80 MΩ when enabled).

Signal conditioning includes integrated reference inputs (REFP/REFN), analog/digital ground separation (AGND/DGND), and dedicated SYNC/PWDN and RESET pins for system-level timing control and power management. The device supports self- and system calibration for offset and gain errors across all PGA gains.

Key Specifications

Pinout & Package

The ADS1257IRGWT is housed in a 20-pin VQFN package (5.00 mm × 5.00 mm) with exposed thermal pad connected to AGND. Pin functions are validated per TI SBAS656B datasheet Rev. B (April 2016).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS1256IRTB, the ADS1257IRGWT offers fewer analog inputs but integrates sensor break detection and uses a smaller 20-pin footprint; versus AD7739BRUZ, it provides higher speed, on-chip PGA, and superior 50/60-Hz rejection-making it optimal for compact, self-diagnosing industrial sensors.

Availability

ADS1257IRGWT is available at Aetrix Electronics and suitable for factory automation, test and measurement, and medical equipment requiring stable component supply, long-lifecycle support, and guaranteed traceability.

Supply support for ADS1257IRGWT 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 company specializing in analog and embedded processing technologies, with leadership in precision data converters and industrial-grade ICs.

The ADS1257IRGWT belongs to TI's precision delta-sigma ADC product line, designed specifically for high-accuracy, low-drift industrial and instrumentation applications where sensor integrity, noise immunity, and long-term stability are critical.

FAQ

What is the maximum achievable noise-free resolution of the ADS1257IRGWT?

The ADS1257IRGWT achieves up to 23 bits of noise-free resolution at 2.5 SPS with buffer enabled and PGA gain = 1, as confirmed in TI SBAS656B datasheet Table 2. This value drops to 19.1 bits at 30 kSPS under identical conditions-reflecting the inherent noise–speed tradeoff in delta-sigma architectures. The ADS1257IRGWT's resolution is measured using peak-to-peak noise, not RMS, ensuring conservative real-world usability.

Does the ADS1257IRGWT support simultaneous sampling across its analog inputs?

No, the ADS1257IRGWT does not support true simultaneous sampling. It uses a single delta-sigma modulator with an internal analog multiplexer to sequentially sample up to four inputs. However, its SYNC/PWDN pin enables synchronized start-of-conversion across multiple ADS1257IRGWT devices in a system, providing deterministic inter-device timing alignment for pseudo-simultaneous acquisition.

How does the sensor break detection feature work on the ADS1257IRGWT?

The ADS1257IRGWT implements sensor break detection using programmable current sources (0.5 µA, 2 µA, or 10 µA) that inject current into selected analog inputs (AIN0–AIN3). An open circuit causes measurable voltage deviation at the input, which the device detects during conversion cycles. This function is fully configurable via registers and requires no external components-ensuring reliable electrode or sensor cable integrity verification in medical and industrial systems using the ADS1257IRGWT.

Can the ADS1257IRGWT operate with a 3.3-V digital supply while maintaining 5-V analog performance?

Yes, the ADS1257IRGWT supports independent digital and analog supplies: DVDD may be set from 1.8 V to 3.6 V (including 3.3 V), while AVDD remains at 4.75–5.25 V. Its digital I/Os-including SCLK, DIN, DOUT, CS, RESET, and SYNC/PWDN-are 5-V tolerant, allowing direct interfacing with 5-V microcontrollers without level shifters. This dual-supply architecture preserves full 24-bit analog performance while enabling low-power digital domain operation in the ADS1257IRGWT.

What is the purpose of the D0/CLKOUT pin on the ADS1257IRGWT?

The D0/CLKOUT pin on the ADS1257IRGWT serves a dual function: as a general-purpose digital I/O (D0) or as a buffered output of the internal master clock (CLKOUT). When configured as CLKOUT, it provides a divided version of the CLKIN signal-useful for synchronizing external circuitry like DACs or digital isolators. As D0, it supports bidirectional control of peripherals such as multiplexer enable lines or LED indicators, enhancing system integration without requiring additional GPIO expanders in designs using the ADS1257IRGWT.