Texas Instruments ADS8481IBRGZT

Overview

ADS8481IBRGZT from Texas Instruments is an 18-bit, 1-MSPS pseudo-differential unipolar SAR analog-to-digital converter with integrated 4.096-V reference, ±0.1 mV offset error, 0.2 ppm/°C offset drift, and 7×7 mm QFN-48 package. It delivers zero-latency conversion, 94 dB SNR at 1 kHz, and supports 8-/16-/18-bit parallel bus transfer for high-accuracy data acquisition in medical instruments and transducer interfaces.

For engineers reviewing the ADS8481IBRGZT datasheet, ADS8481IBRGZT pinout, ADS8481IBRGZT application, or ADS8481IBRGZT equivalent, key selection criteria include guaranteed 18-bit no-missing-codes performance over –40°C to 85°C, internal reference buffer capability, BUSY-driven timing control, and compatibility with 2.7–5.25 V digital supply rails.

Technical Context

The ADS8481IBRGZT employs a capacitor-based successive approximation register (SAR) architecture with inherent sample-and-hold, enabling zero-latency operation and 710 ns conversion time. Its pseudo-differential input accepts unipolar signals from 0 V to V_REF, with dedicated +IN/–IN terminals and REFM tied to AGND.

It integrates a double-buffered 4.096-V internal reference with 6 ppm/°C drift and supports external reference operation via REFIN (3.0–4.2 V). Parallel interface logic includes BUS18/16 and BYTE inputs to configure 18-bit, 16-bit (two-cycle), or 8-bit (three-cycle) data reads, all synchronized by CONVST, CS, RD, and BUSY signals.

Key Specifications

Pinout & Package

The ADS8481IBRGZT is housed in a 7×7 mm, 48-pin QFN package (RGZ) with exposed thermal pad requiring soldering to PCB for thermal and mechanical integrity. Pin functions are validated per TI SLAS385A datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8482IRGZT and ADS8381IPWR, the ADS8481IBRGZT uniquely balances 1-MSPS speed, unipolar pseudo-differential input simplicity, integrated reference, and industrial temperature guarantee-making it optimal for cost-sensitive, high-accuracy single-supply sensor digitization.

Availability

ADS8481IBRGZT is available at Aetrix Electronics and suitable for medical instrumentation, optical networking equipment, transducer interface systems, and high-accuracy data acquisition requiring stable component supply across extended temperature ranges.

Supply support for ADS8481IBRGZT 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, embedded processing, and connectivity technologies with decades of precision data converter innovation.

The ADS8481IBRGZT belongs to TI's high-speed SAR ADC family designed for applications demanding 18-bit accuracy, zero latency, and robust parallel interfacing in industrial, medical, and communications infrastructure.

FAQ

What is the guaranteed integral nonlinearity (INL) specification for the ADS8481IBRGZT?

The ADS8481IBRGZT guarantees ±3.5 LSB integral nonlinearity over the full industrial temperature range (–40°C to +85°C), as specified in the TI SLAS385A datasheet. This performance level ensures monotonic behavior and supports high-precision measurement applications without requiring end-system INL correction. The ADS8481IBRGZT achieves this using a trimmed capacitor DAC array and matched layout techniques inherent to its SAR architecture.

Does the ADS8481IBRGZT require an external reference, or can it operate with its internal reference?

The ADS8481IBRGZT can operate with either its internal 4.096-V reference or an external reference applied to the REFIN pin (3.0–4.2 V range). When using the internal reference, REFOUT must be connected to REFIN via a 0.1-µF capacitor, and a 1-µF storage capacitor must be placed between REFOUT and REFM. The internal reference is double-buffered to isolate switching noise, making the ADS8481IBRGZT self-contained for many precision applications.

How does the BUS18/16 and BYTE pin configuration affect data readout timing on the ADS8481IBRGZT?

On the ADS8481IBRGZT, BUS18/16 = 0 configures an 18-bit parallel bus (DB[17:0]), while BUS18/16 = 1 enables 16-bit mode with D[1:0] folded to DB[9:2] or DB[17:10] depending on BYTE state. BYTE = 1 selects high-byte folding; BYTE = 0 selects low-byte folding. All modes use the same BUSY-driven handshake and identical t_en (20 ns) and t_dis (20 ns) timing, preserving deterministic read latency regardless of bus width.

What is the power consumption of the ADS8481IBRGZT at 1 MSPS, and how is it distributed between analog and digital supplies?

At 1 MSPS, the ADS8481IBRGZT consumes 44–48 mA from the +VA (5 V) analog supply and ~1 mA from the +VBD (3.3 V or 5 V) digital supply, resulting in total power dissipation of 220–240 mW. The majority of power (≈215 mW) is consumed by the SAR core, reference buffer, and analog front-end; only ≈5 mW powers the parallel interface logic. This distribution allows independent optimization of analog and digital power domains.

Can the ADS8481IBRGZT interface directly with an 8-bit microcontroller, and what signals are required?

Yes-the ADS8481IBRGZT supports direct 8-bit microcontroller interfacing using BYTE = 1 and BUS18/16 = 1 to fold the 16 MSBs across two 8-bit reads. Required signals are CONVST (start), BUSY (interrupt), RD (read strobe), CS (chip select), and DB[7:0] (data bus). No level-shifting is needed if +VBD matches the MCU's I/O voltage (2.7–5.25 V). TI Application Report SLAS385A Figure 36 provides a verified schematic.