Texas Instruments ADS1256IDBTG4

Overview

ADS1256IDBTG4 from Texas Instruments is a 24-bit delta-sigma analog-to-digital converter with four differential or eight single-ended inputs, 23-bit noise-free resolution at 2.5 SPS, ±0.0010% nonlinearity (max), and SPI-compatible serial interface. It integrates a chopper-stabilized input buffer, programmable gain amplifier (1–64), sensor detect circuitry, and self/system calibration - deployed in high-precision weigh scales and medical instrumentation requiring stable low-noise DC measurement.

For engineers reviewing the ADS1256IDBTG4 datasheet, ADS1256IDBTG4 pinout, ADS1256IDBTG4 application, or ADS1256IDBTG4 equivalent, key selection criteria include noise-free resolution vs. data rate tradeoff (2.5–30 kSPS), PGA-dependent input-referred noise (as low as 27 nV rms), 5-V tolerant digital I/Os, dual-supply operation (AVDD = 5 V, DVDD = 1.8–3.6 V), and SSOP-28 package compatibility with industrial PCB layouts.

Technical Context

The ADS1256IDBTG4 employs a 4th-order delta-sigma modulator followed by a programmable digital filter, enabling configurable resolution/speed optimization. Its flexible input multiplexer supports open/short sensor detection via selectable 0.5/2/10 µA current sources, and the chopper-stabilized buffer delivers up to 80 MΩ input impedance when enabled.

Calibration is supported for all PGA settings via self- and system-offset/gain correction. The SPI-compatible 2-wire serial interface operates with 5-V-tolerant DIN, SCLK, CS, RESET, SYNC/PDWN, and XTAL1/CLKIN pins, while D0/CLKOUT, D1–D3 serve as Schmitt-trigger digital I/Os with programmable clock output capability.

Key Specifications

Pinout & Package

ADS1256IDBTG4 is housed in a 28-pin SSOP (Shrink Small Outline Package) with 0.65-mm lead pitch, optimized for compact industrial PCB layouts and thermal performance in extended temperature environments (−40°C to +105°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS1256IDBTG4, ADS1258IRTCT offers higher throughput and channel density but sacrifices integrated sensor integrity verification, while AD7739BRUZ trades speed and feature set for lower system cost - making ADS1256IDBTG4 optimal for applications demanding balanced resolution, diagnostics, and ease of integration in space-constrained SSOP layouts.

Availability

ADS1256IDBTG4 is available at Aetrix Electronics and suitable for weigh scales, medical instrumentation, scientific instrumentation, and industrial process control requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADS1256IDBTG4 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 industrial-grade ICs.

The ADS1256IDBTG4 belongs to TI's high-precision delta-sigma ADC product line, engineered specifically for applications demanding ultra-low noise, high linearity, and integrated sensor interface features in harsh industrial and medical environments.

FAQ

What is the maximum achievable noise-free resolution of the ADS1256IDBTG4 and under what conditions?

The ADS1256IDBTG4 achieves up to 23 bits of noise-free resolution at 2.5 SPS with the input buffer enabled and PGA = 1, measured with inputs shorted and VREF = 2.5 V. This value drops to 17.1 bits at 30 kSPS due to increased quantization noise - a fundamental tradeoff inherent to delta-sigma architecture. The datasheet Table 3 confirms this behavior across all PGA settings and data rates.

Does the ADS1256IDBTG4 support true differential input measurements, and how many independent differential channels does it provide?

Yes, the ADS1256IDBTG4 supports true differential measurements using any two of its nine analog input pins (AIN0–AIN7 plus AINCOM) as AINP and AINN. It provides four independent differential input channels - for example, AIN0/AIN1, AIN2/AIN3, AIN4/AIN5, and AIN6/AIN7 - as explicitly defined in the device description and pin assignment tables of the SBAS288K datasheet.

How does the sensor detect function operate in the ADS1256IDBTG4, and what current levels are available?

The ADS1256IDBTG4 implements sensor detect via programmable current sources (SDCS) that inject 0.5 µA, 2 µA, or 10 µA into selected input pins. When enabled, the internal buffer activates automatically, and the resulting voltage drop across the sensor (plus 50 Ω mux resistance) is digitized to identify opens or shorts. This function is confirmed in Section 15 ("Open/Short Sensor Detection") of the SBAS288K datasheet.

What are the absolute maximum ratings for AVDD and DVDD supplies on the ADS1256IDBTG4?

The ADS1256IDBTG4 has an absolute maximum AVDD rating of −0.3 V to +6 V relative to AGND, and DVDD must remain between −0.3 V and +3.6 V relative to DGND. These limits are specified in the "Absolute Maximum Ratings" table (page 2) of SBAS288K. Exceeding them risks permanent damage, and recommended operating ranges are AVDD = 4.75–5.25 V and DVDD = 1.8–3.6 V.

Can the ADS1256IDBTG4 operate with a 3.3-V digital supply while maintaining full SPI compatibility and timing specifications?

Yes, the ADS1256IDBTG4 fully supports DVDD = 3.3 V operation: all digital inputs (DIN, SCLK, CS, etc.) are 5-V tolerant, VIH is defined as 0.8 × DVDD (2.64 V min), and timing parameters (e.g., t1, t2H) scale with τCLKIN - not DVDD. Electrical Characteristics tables (pages 3–4) explicitly list performance data at DVDD = 3.3 V, including 2 mA normal-mode current and 57 mW power dissipation.