Texas Instruments ADS8381IBPFBT

Overview

ADS8381IBPFBT from Texas Instruments is an 18-bit, 580-kHz successive approximation register (SAR) analog-to-digital converter with zero latency, unipolar input range, and integrated reference buffer. It features 48-pin TQFP packaging, 115 mW power dissipation at full throughput, and guaranteed 18-bit no-missing-codes performance over −40°C to +85°C for high-accuracy data acquisition in magnetometers and optical networking equipment.

For engineers reviewing the ADS838381IBPFBT datasheet, ADS8381IBPFBT pinout, ADS8381IBPFBT application, or ADS8381IBPFBT equivalent, this page delivers verified timing parameters, parallel interface configuration options (8-/16-/18-bit), absolute maximum ratings, and real-world SNR/SFDR performance at 100 kHz input - all critical for medical instrument signal chain design and transducer interface validation.

Technical Context

The ADS8381IBPFBT implements a capacitor-based SAR architecture with inherent sample-and-hold, eliminating external hold circuitry. Its internal conversion clock enables fixed 1.4 µs conversion time and 0.3 µs acquisition time, supporting deterministic 580-kHz throughput without pipeline delay.

It supports three parallel bus modes via BUS18/16 and BYTE control inputs: full 18-bit output, 16-bit two-cycle read, or 8-bit three-cycle read. The device uses separate analog (+VA) and digital buffer (+VBD) supplies (4.75–5.25 V and 2.7–5.25 V respectively), with dedicated AGND and BDGND pins to maintain noise isolation between signal and logic domains.

Key Specifications

Pinout & Package

ADS8381IBPFBT is housed in a 48-pin TQFP package (PFB designation), with exposed thermal pad, 0.5 mm pitch, and JEDEC MO-220 standard footprint. Pin layout separates analog, digital, and ground domains to minimize coupling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8383IPFBT, the ADS8381IBPFBT trades 2.15× lower throughput for tighter INL (±5 vs ±6 LSB) and lower power (115 mW vs ~160 mW), while AD7606C-18BSTZ offers channel integration at the cost of interface flexibility and board space - making ADS8381IBPFBT optimal for single-channel, low-jitter, thermally constrained precision systems.

Availability

ADS8381IBPFBT is available at Aetrix Electronics and suitable for medical instrumentation, optical networking equipment, and transducer interface modules requiring stable component supply, long-term lifecycle support, and traceable industrial-grade sourcing.

Supply support for ADS8381IBPFBT 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 chain solutions.

The ADS8381IBPFBT belongs to TI's high-speed precision SAR ADC product line, designed specifically for applications demanding zero-latency, 18-bit accuracy, and robust operation in noisy industrial and medical environments.

FAQ

What is the maximum sample rate supported by the ADS8381IBPFBT?

The ADS8381IBPFBT supports a maximum sample rate of 580 kHz, achieved through its fixed 1.4 µs conversion time and 0.3 µs acquisition time. This rate is fully characterized over the −40°C to +85°C industrial temperature range and maintains 18-bit no-missing-codes performance, SNR ≥87 dB, and SFDR ≥97 dB at 100 kHz input frequency - enabling reliable real-time capture in high-fidelity sensor interfaces.

Does the ADS8381IBPFBT require an external reference voltage?

Yes, the ADS8381IBPFBT requires an external reference voltage applied to the REFIN pin, with a valid range of 2.5 V to 4.2 V. The device includes an internal reference buffer, but external decoupling (0.1 µF capacitor between REFIN and REFM) is mandatory to achieve specified INL and SNR performance. A low-noise bandgap reference such as the REF3040 is recommended to ensure <±5 LSB integral nonlinearity across temperature.

How does the parallel interface of the ADS8381IBPFBT support different microcontroller bus widths?

The ADS8381IBPFBT supports 8-bit, 16-bit, and 18-bit parallel data transfers using the BUS18/16 and BYTE control inputs. When BUS18/16 = 0, all 18 bits appear on DB[17:0]; when BUS18/16 = 1 and BYTE = 0, the 16 MSBs are split across two 8-bit reads; when BYTE = 1, folding logic maps D[9:2] to DB[17:10]. This eliminates external multiplexing logic and enables direct connection to 8-bit MCUs like the MSP430 or STM32 series.

What is the purpose of separate +VA and +VBD supply pins on the ADS8381IBPFBT?

The ADS8381IBPFBT uses separate +VA (analog supply, 4.75–5.25 V) and +VBD (buffer/digital supply, 2.7–5.25 V) to isolate noise-sensitive analog circuitry from digital switching transients. +VA powers the SAR core and reference buffer; +VBD powers the parallel output drivers and interface logic. This separation, combined with dedicated AGND and BDGND pins, achieves >75 dB power supply rejection ratio and prevents digital noise from degrading ADC accuracy - critical for achieving 18-bit linearity.

Is the ADS8381IBPFBT pin-compatible with other devices in the same family?

Yes, the ADS8381IBPFBT is pin-compatible with the ADS8383 in the same 48-pin TQFP (PFB) package, sharing identical pin assignments for power, ground, analog inputs, reference, control signals (CONVST, CS, RD, BUSY), and data bus lines (DB[17:0]). This allows hardware reuse and migration paths - for example, upgrading to the ADS8383IPFBT for higher 1.25 MSPS throughput without changing PCB layout or interconnect design.