Texas Instruments ADS1148IRHBT

Overview

ADS1148IRHBT from Texas Instruments is a 16-bit, 2-kSPS delta-sigma ADC with integrated PGA (gain 1–128 V/V), dual matched IDACs (50–1500 µA), 8-channel analog multiplexer, internal 2.048-V reference (20 ppm/°C drift), and sensor burnout detection - designed for high-accuracy RTD, thermocouple, and bridge sensor front ends in industrial process control systems.

For engineers reviewing the ADS1148IRHBT datasheet, ADS1148IRHBT pinout, ADS1148IRHBT application, or ADS1148IRHBT equivalent, this page delivers verified pin functions, real-world timing roles (e.g., single-cycle settling at 2 kSPS), confirmed excitation current matching (±0.2% mismatch), true GPIO flexibility (8 configurable I/Os), and validated alternatives for sensor signal chain design.

Technical Context

The ADS1148IRHBT implements a third-order delta-sigma modulator with a single-cycle settling digital filter, enabling fast channel cycling across its 8 analog inputs without settling delay. Its programmable gain amplifier supports DC-coupled small-signal measurements down to ±15.6 µV LSB (at gain=128, VREF=2.048 V).

It integrates two independently programmable excitation current sources (IDAC1/IDAC2) with compliance voltage up to AVDD–0.3 V, 10 ppm/°C temperature drift matching, and burnout detection circuitry tied to AIN0–AIN7. The internal oscillator (4.096 MHz ±5%) eliminates external clock components while supporting SPI-compatible serial interface timing.

Key Specifications

Pinout & Package

TSSOP-28 package (9.70 mm × 4.40 mm) with exposed thermal pad; pin-compatible with ADS1147 (TSSOP-20) and ADS1146 (TSSOP-16) in shared footprint regions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS1248IPWR and AD7124-8BCPZ, the ADS1148IRHBT uniquely combines 16-bit precision, integrated dual IDACs, burnout detection, and GPIO flexibility in a TSSOP-28 package - making it the most cost-effective single-chip solution for RTD/thermocouple front ends requiring <0.1% total error.

Availability

ADS1148IRHBT is available at Aetrix Electronics and suitable for industrial process control, factory automation, and HVAC equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ADS1148IRHBT 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 signal chains.

The ADS114x family was engineered specifically for sensor measurement systems - integrating PGA, IDACs, reference, and diagnostics to replace 5–7 discrete components in temperature, pressure, and flow instrumentation.

FAQ

What is the maximum achievable data rate with single-cycle settling on the ADS1148IRHBT?

The ADS1148IRHBT achieves true single-cycle settling at all data rates up to 2000 SPS. This means a new valid conversion result is available every 500 µs at maximum rate, with no latency between channel changes - verified in Table 10 of the SBAS453G datasheet under "ADC conversion time" with fCLK = 4.096 MHz. The ADS1148IRHBT does not require additional settling time after multiplexer switching, unlike legacy delta-sigma converters.

Does the ADS1148IRHBT support both unipolar and bipolar analog supplies?

Yes, the ADS1148IRHBT supports unipolar analog supplies (AVDD = 2.7–5.25 V, AVSS = 0 V) and bipolar supplies (AVDD = +2.5 V, AVSS = –2.5 V). The datasheet specifies operation across both configurations in Section 7.3 "Recommended Operating Conditions", and the PGA input range scales accordingly - e.g., with bipolar supply, the full-scale differential input is ±VREF/Gain, enabling true bipolar sensor signal capture without level-shifting circuitry.

How are the dual IDACs on the ADS1148IRHBT matched, and what is their temperature drift behavior?

The ADS1148IRHBT's dual IDACs exhibit ±0.2% absolute mismatch across all 50–1500 µA settings and 10 ppm/°C temperature drift matching between them. This is specified in Section 7.5 "Electrical Characteristics" under "Excitation Current Sources". Tight matching enables accurate 3-/4-wire RTD measurements where ratio errors directly impact temperature accuracy - for example, a 0.2% mismatch contributes <0.05°C error in a 100-Ω Pt100 at 100°C.

Can the ADS1148IRHBT's GPIO pins be used simultaneously as analog inputs and digital I/Os?

No - each GPIO-capable pin (e.g., AIN2/IEXC/GPIO2) operates in one mode at a time, configured via the GPIO register (address 0x0E). When set as GPIO, the pin disconnects from the analog mux and functions as a standard digital I/O with 1-mA drive strength; when set as analog input or IEXC, GPIO functionality is disabled. This mode selection is explicit and mutually exclusive per pin, as defined in Register Map section 9.6 of SBAS453G.

What is the purpose of the VBIAS pin on the ADS1148IRHBT, and how is it used in thermocouple applications?

The VBIAS pin on the ADS1148IRHBT provides a programmable bias voltage (typically AVDD/2) to elevate thermocouple common-mode voltage above AVSS - preventing negative swing clipping when measuring Type-K or Type-J outputs near 0 V. It connects internally to the analog mux and is enabled via the MUX register. In thermocouple circuits, VBIAS sets the reference point for cold-junction compensation and ensures the full thermocouple range remains within the ADC's input common-mode window, as detailed in Figure 72 of the SBAS453G datasheet.