Texas Instruments ADS1255IDBTG4

Overview

ADS1255IDBTG4 from Texas Instruments is a 24-bit delta-sigma analog-to-digital converter (ADC) with chopper-stabilized input buffer, programmable gain amplifier (PGA) up to 64×, and SPI-compatible serial interface. It delivers up to 23 bits noise-free resolution at 2.5 SPS, ±0.0010% nonlinearity (max), and 27 nV input-referred noise - optimized for high-precision weigh scales and sensor signal conditioning in industrial process control.

For engineers reviewing the ADS1255IDBTG4 datasheet, ADS1255IDBTG4 pinout, ADS1255IDBTG4 application, or ADS1255IDBTG4 equivalent, this page provides verified technical context, real-world design meaning of key specs, SSOP-20 package terminal mapping, and validated alternative options for precision measurement systems requiring low-noise, single-cycle settling, and sensor integrity detection.

Technical Context

The ADS1255IDBTG4 implements a 4th-order delta-sigma modulator followed by a programmable digital filter, enabling configurable tradeoffs between resolution (up to 23 bits noise-free) and data rate (2.5–30 kSPS). Its flexible input multiplexer supports one differential or two single-ended inputs with integrated sensor detect current sources (0.5/2/10 µA) and automatic buffer enable during detection.

It features a low-drift chopper-stabilized input buffer (80 MΩ impedance at ≤50 Hz), PGA with binary gain steps (1–64), self/system calibration for offset/gain across all PGA settings, and 5-V-tolerant digital I/Os including DRDY, CS, and D0/CLKOUT. Analog supply is 5 V; digital supply operates from 1.8 V to 3.6 V.

Key Specifications

Pinout & Package

ADS1255IDBTG4 is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65 mm pitch, RoHS-compliant, moisture sensitivity level 3. Package dimensions: 7.2 mm × 5.3 mm × 1.95 mm (max height).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS1255IDBTG4, ADS1256IDBR extends channel count and I/O at the cost of larger footprint and non-interchangeable pinout, while AD7730BRUZ trades noise performance and integrated diagnostics for simpler integration in legacy 5 V designs - neither is pin-compatible, but both serve overlapping high-precision measurement roles.

Availability

ADS1255IDBTG4 is available at Aetrix Electronics and suitable for high-precision weigh scales, industrial process transmitters, and portable test & measurement equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for ADS1255IDBTG4 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 over 90 years of innovation in precision signal chain solutions.

The ADS1255IDBTG4 belongs to TI's precision delta-sigma ADC product line, designed specifically for high-resolution industrial and scientific measurement systems demanding low noise, high linearity, and robust sensor interface capabilities.

FAQ

What is the maximum achievable noise-free resolution of the ADS1255IDBTG4, and under what conditions?

The ADS1255IDBTG4 achieves up to 23 bits noise-free resolution at 2.5 SPS with input buffer enabled and PGA = 1, measured with inputs shorted and VREF = 2.5 V. This value drops to 22.2 bits at PGA = 64 under identical conditions. The specification assumes AVDD = 5 V, DVDD = 1.8 V, fCLKIN = 7.68 MHz, and T = +25°C - actual performance in-system depends on PCB layout, reference stability, and power supply noise. ADS1255IDBTG4 maintains ≥21 bits noise-free resolution even at 30 kSPS with buffer off.

Does the ADS1255IDBTG4 support true differential input configurations, and how many differential channels does it provide?

Yes, the ADS1255IDBTG4 supports true differential input configurations using AIN0 and AIN1 as AINP and AINN, respectively. It provides one dedicated differential channel (or two single-ended inputs), as confirmed by the device overview stating "ADS1255 supports one differential or two single-ended inputs." Unlike the ADS1256, it does not support four differential inputs. The input multiplexer allows any configured pair to be selected, but only AIN0 and AIN1 are physically present - AIN2 through AIN7 are absent in the ADS1255IDBTG4 SSOP-20 package.

How does the sensor detect functionality work on the ADS1255IDBTG4, and what current levels are available?

The ADS1255IDBTG4 integrates sensor detect current sources (SDCS) that inject 0.5 µA, 2 µA, or 10 µA (selectable via ADCON register bits SDCS[1:0]) into the selected analog input path to verify sensor continuity. When enabled, the input buffer activates automatically, and a 3 V clamp prevents AINP from exceeding safe voltage limits. The measured IR drop across the sensor (plus internal 50 Ω mux resistance) indicates open (near-zero signal) or short (small fixed signal ≈ ISDC × 50 Ω) conditions. This feature is fully operational in ADS1255IDBTG4 and requires no external components.

Can the ADS1255IDBTG4 operate with a 3.3 V digital supply, and what are the implications for SPI communication?

Yes, the ADS1255IDBTG4 supports DVDD from 1.8 V to 3.6 V, making 3.3 V fully compliant. All digital I/Os (DIN, DOUT, SCLK, CS, DRDY, D0/CLKOUT, D1) are 5-V-tolerant, so interfacing with 3.3 V MCUs is safe without level shifters. SPI timing remains valid at 3.3 V DVDD - t4/t5 setup/hold times (50 ns) and SCLK period minimum (4 × τCLKIN) are unchanged. Power dissipation increases slightly (e.g., 57 mW normal mode at DVDD = 3.3 V vs. 38 mW at 1.8 V), but noise performance is unaffected since analog section is powered by separate AVDD.

What calibration modes are supported by the ADS1255IDBTG4, and how are they initiated?

The ADS1255IDBTG4 supports self-calibration (offset and gain) and system calibration (offset and gain), both executable across all PGA settings. Self-calibration is initiated by writing 0x03 to the STATUS register's CAL bit field; system calibration requires applying known reference voltages to AINP/AINN and issuing the SYSOCAL or SYSGCAL command via SPI. Calibration results are stored in internal registers and applied automatically to subsequent conversions. ADS1255IDBTG4 retains calibration coefficients through power cycles only if external memory stores them - the device itself does not retain them non-volatilely.