Texas Instruments ADS8422IBPFBT

Overview

ADS8422IBPFBT from Texas Instruments is a 16-bit, 4-MSPS pseudo-bipolar fully differential SAR analog-to-digital converter with integrated 4.096-V reference, 92 dB SNR at 100 kHz, ±1 LSB INL (typ), and parallel 16-bit/8-bit bus interface - used in high-precision data acquisition for spectrum analysis and medical instrumentation.

For engineers reviewing the ADS8422IBPFBT datasheet, ADS8422IBPFBT pinout, ADS8422IBPFBT application, or ADS8422IBPFBT equivalent, key selection considerations include its zero-latency SAR architecture, internal reference buffer capability, REFIN/2 common-mode output on COMMOUT, and industrial −40°C to +85°C operation in 48-pin TQFP.

Technical Context

The ADS8422IBPFBT implements a capacitor-based multi-bit SAR architecture with inherent sample-and-hold, internal oscillator-driven conversion clock, and fully differential pseudo-bipolar input range of −4 V to +4 V. It supports true zero-latency operation with no pipeline delay.

Its digital interface includes asynchronous CONVST-triggered conversion, BUSY status flag, CS/RD-controlled parallel readout, BYTE-selectable 8-bit or full 16-bit output, and dual power-down pins (PD1 for ADC reset/powerdown, PD2 for REFOUT/COMMOUT buffers) - all compliant with CMOS logic levels across +VBD = 2.7–5.25 V.

Key Specifications

Pinout & Package

ADS8422IBPFBT is housed in a 48-pin 9×9 mm TQFP (PFB) package with exposed thermal pad. Pin functions are validated per TI SLAS512B datasheet (December 2006 revision).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8412IPFBT and ADS8402IPFBT, the ADS8422IBPFBT delivers highest throughput (4 MSPS), best linearity (±1 LSB INL), and lowest THD (−102 dB), making it optimal for demanding real-time spectral and medical applications where speed and fidelity are co-critical.

Availability

ADS8422IBPFBT is available at Aetrix Electronics and suitable for high-speed data acquisition, spectrum analysis, and medical instrumentation requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for ADS8422IBPFBT 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 leadership in precision data converters and industrial-grade ICs.

The ADS8422IBPFBT belongs to TI's high-speed SAR ADC family designed for zero-latency, high-resolution digitization in test & measurement, medical imaging, and communications infrastructure - emphasizing speed, linearity, and integrated reference integrity.

FAQ

What is the maximum input frequency supported by the ADS8422IBPFBT without significant dynamic performance degradation?

The ADS8422IBPFBT specifies a maximum input frequency (f_i(max)) of 2 MHz for 8-Vpp signals, beyond which SNR and SFDR degrade rapidly. Its −3dB small-signal bandwidth is 30 MHz, but dynamic specifications (e.g., 92 dB SNR, −102 dB THD) are guaranteed only up to 2 MHz per the datasheet. For optimal performance at 100 kHz, the ADS8422IBPFBT maintains full 16-bit linearity and noise floor integrity.

Does the ADS8422IBPFBT require an external clock source to operate?

No, the ADS8422IBPFBT uses an internal oscillator to generate its conversion clock and requires no external clock input. Conversion is initiated solely by the CONVST signal, and the device sustains a fixed 4-MSPS throughput with 180 ns conversion time and 70 ns acquisition time - all internally timed and jitter-optimized.

How does the COMMOUT pin (Pin 3) function in the ADS8422IBPFBT, and what is its design purpose?

The COMMOUT pin on the ADS8422IBPFBT outputs REFIN/2 (i.e., 2.048 V when using the internal 4.096-V reference) and serves as a precision common-mode voltage source for driving differential input amplifiers. This eliminates need for external resistor dividers and ensures matched biasing of +IN and –IN, directly supporting the device's pseudo-bipolar input range of −4 V to +4 V.

What are the power-down states supported by the ADS8422IBPFBT, and how do PD1 and PD2 differ in function?

The ADS8422IBPFBT supports two independent power-down modes: PD1 (Pin 38) resets the ADC and can power down the core ADC circuitry (reducing +VA current to 3.4 mA), while PD2 (Pin 37) powers down only the REFOUT and COMMOUT buffers (saving ~17 mW). The combination PD1=1, PD2=0 is reserved and must not be used per datasheet specification.

Is the ADS8422IBPFBT pin-compatible with other devices in the ADS84xx family, and which models share the same PFB package?

Yes, the ADS8422IBPFBT is pin-compatible with ADS8412IPFBT and ADS8402IPFBT in the same 48-pin PFB package. All three share identical pin assignments for power, ground, analog inputs, reference, CONVST, BUSY, CS, RD, BYTE, and DB[15:0], enabling drop-in upgrades from 2-MSPS (ADS8402) or 3-MSPS (ADS8412) to 4-MSPS performance without PCB redesign.