Texas Instruments ADS8405IBPFBT

Overview

ADS8405IBPFBT from Texas Instruments is a 16-bit, 1.25-MSPS unipolar pseudo-differential SAR analog-to-digital converter with integrated 4.096-V reference, parallel interface, and zero-latency operation. It delivers ±1 LSB DNL max, 86 dB SNR at 100 kHz, and operates from single 5-V analog supply with 2.7–5.25-V I/O voltage range. Used in high-resolution data acquisition for medical instruments and transducer interfaces.

For engineers reviewing the ADS8405IBPFBT datasheet, ADS8405IBPFBT pinout, ADS8405IBPFBT application, or ADS8405IBPFBT equivalent, this page provides verified technical context, real-world timing constraints, package-specific layout guidance, and validated alternative options for industrial-grade signal chain design.

Technical Context

The ADS8405IBPFBT implements a capacitor-based successive approximation register (SAR) architecture with inherent sample-and-hold, enabling true zero-latency conversion. Its internal oscillator eliminates external clock dependency, and the 650-ns conversion time supports sustained 1.25-MHz throughput without pipeline delay.

It features dual-mode parallel output: full 16-bit bus (DB15–DB0) when BYTE = 0, or two 8-bit reads via DB15–DB8 with BYTE toggling. The pseudo-differential input accepts 0 V to V_REF span (+IN – (–IN)), with –IN limited to ±0.2 V and +IN to –0.2 V to V_REF + 0.2 V - enforcing unipolar operation while rejecting common-mode noise below 0.2 V.

Key Specifications

Pinout & Package

ADS8405IBPFBT is housed in a 48-pin TQFP (PFB) package with exposed thermal pad, rated for –40°C to +85°C industrial operation. Pin assignments are validated per TI SLAS427 datasheet Figure 6 and Terminal Functions table.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8411IPFBT and ADS8401IBPFBT, the ADS8405IBPFBT uniquely balances 16-bit no-missing-code performance, unipolar pseudo-differential simplicity, and integrated reference - making it optimal for sensor-to-digital systems where board space, power, and analog front-end complexity are constrained.

Availability

ADS8405IBPFBT is available at Aetrix Electronics and suitable for medical instrumentation, industrial data acquisition, transducer interface, and communications test equipment requiring stable component supply and long-term manufacturability.

Supply support for ADS8405IBPFBT 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 signal chain solutions.

The ADS8405IBPFBT belongs to TI's high-speed SAR ADC family designed for applications demanding zero-latency, high SNR, and integrated reference - targeting medical, test & measurement, and industrial automation markets.

FAQ

What is the maximum sampling rate supported by the ADS8405IBPFBT?

The ADS8405IBPFBT supports a guaranteed maximum throughput rate of 1.25 MSPS across its full industrial temperature range (–40°C to +85°C). This is achieved with a typical conversion time of 650 ns and acquisition time of 150 ns, enabling continuous sampling without dead time between conversions. The device uses an internal oscillator, so no external clock is required to sustain this rate.

Does the ADS8405IBPFBT require an external reference voltage?

No, the ADS8405IBPFBT includes a factory-trimmed 4.096-V internal reference with ±36 ppm/°C drift and 0.6 mV line regulation. When used, REFOUT (pin 2) must connect to REFIN (pin 1) via a 0.1-µF capacitor and to REFM (pins 47/48) via a 1-µF storage capacitor. An external reference (2.5–4.2 V) may be applied to REFIN if higher initial accuracy or custom voltage scaling is needed - but the internal reference eliminates BOM and layout overhead for most applications.

How does the BYTE pin function on the ADS8405IBPFBT?

The BYTE pin (pin 39) controls data bus configuration: when LOW, DB15–DB0 output the full 16-bit result (D15–D0); when HIGH, DB15–DB8 output the lower byte (D7–D0), while DB7–DB0 go high-impedance. This enables 8-bit microcontroller interfacing via two sequential reads - first with BYTE = 0 (MSB), then BYTE = 1 (LSB) - without requiring external latches or address decoding logic.

What are the absolute maximum ratings for analog input pins on the ADS8405IBPFBT?

The ADS8405IBPFBT specifies absolute maximum ratings of –0.4 V to (+VA + 0.1 V) on +IN relative to AGND, and –0.4 V to +0.5 V on –IN relative to AGND. Exceeding these violates safe operating area and risks permanent damage. For normal operation, +IN must stay within –0.2 V to (V_REF + 0.2 V) and –IN within –0.2 V to +0.2 V to maintain specified INL/DNL and avoid gain compression.

Is the ADS8405IBPFBT pin-compatible with other devices in the ADS84xx family?

Yes, the ADS8405IBPFBT is pin-compatible with ADS8401IBPFBT and ADS8411IPFBT in the same 48-pin TQFP (PFB) package. All share identical pin assignments for power, ground, control, and data buses. However, functional differences exist: ADS8401IBPFBT has looser linearity specs (±2 LSB INL), and ADS8411IPFBT uses fully differential inputs - so PCB layout is reusable, but analog front-end and firmware may require revision.