Texas Instruments ADS7890IPFBRG4

Overview

ADS7890IPFBRG4 from Texas Instruments is a 14-bit, 1.25-MSPS successive approximation register (SAR) analog-to-digital converter with integrated 2.5-V reference, pseudo-differential input (0 V to 2.5 V span), SPI/DSP-compatible serial interface, and zero-latency operation. It delivers 77.5 dB SNR and −95 dB THD at 0.5 MHz input frequency and operates in high-speed data acquisition systems requiring precise timing and low noise.

For engineers reviewing the ADS7890IPFBRG4 datasheet, ADS7890IPFBRG4 pinout, ADS7890IPFBRG4 application, or ADS7890IPFBRG4 equivalent, key selection considerations include its 48-pin TQFP package, internal reference buffer, nap mode (10 mW), power-down capability (2.5 µA), and ±1.5 LSB integral linearity over −40°C to +85°C.

Technical Context

The ADS7890IPFBRG4 implements a capacitor-based SAR architecture with inherent sample-and-hold, enabling true zero-latency conversion. Its pseudo-differential input stage accepts +IN (−0.2 V to 2.7 V) and −IN (±0.2 V), supporting ground mismatch compensation and common-mode noise rejection up to 60 dB at 0.5 MHz.

It supports dual digital interfaces: SPI (CS/SCLK/SDO/BUSY) and DSP (CS/SCLK/FS/SDO/BUSY), with frame abort capability across all phases. Conversion timing is internally clocked (365 ns max), and aperture jitter is specified at 20 ps - critical for high-fidelity signal capture in spectrum analyzers and optical networking equipment.

Key Specifications

Pinout & Package

ADS7890IPFBRG4 is housed in a 48-pin TQFP (PFB) package with exposed thermal pad, optimized for analog signal integrity and thermal dissipation in high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS8325IPW and AD7865BSZ-1, the ADS7890IPFBRG4 uniquely balances 1.25 MSPS speed, integrated reference, and ultra-low-power nap mode - making it optimal for portable, high-bandwidth instrumentation where board space and thermal budget are constrained.

Availability

ADS7890IPFBRG4 is available at Aetrix Electronics and suitable for optical networking monitoring, spectrum analyzer front-ends, and high-speed closed-loop control systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for ADS7890IPFBRG4 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 high-performance data converters for industrial, automotive, and communications markets.

The ADS7890IPFBRG4 belongs to TI's high-speed SAR ADC product line, designed specifically for applications demanding zero-latency, high SNR, and flexible power management in compact form factors.

FAQ

What is the maximum input voltage range supported by the ADS7890IPFBRG4?

The ADS7890IPFBRG4 supports a pseudo-differential input range where +IN accepts −0.2 V to (V_REF + 0.2 V) = 2.7 V, and −IN is limited to ±0.2 V. The full-scale differential span is 0 V to 2.5 V. Exceeding these absolute limits risks linearity degradation or damage - confirmed in Absolute Maximum Ratings and Analog Input specifications on page 3 of SLAS409.

Does the ADS7890IPFBRG4 require an external reference, or can it operate with its internal reference?

The ADS7890IPFBRG4 can operate with either its internal 2.5-V reference (buffered, 25 ppm/°C drift) or an external reference applied to REFIN. When using the internal reference, REFOUT must be connected to REFIN with 0.1-µF and 1-µF capacitors to AGND (REFM pins). This configuration eliminates external reference components and is validated across −40°C to +85°C.

How does the nap mode function in the ADS7890IPFBRG4, and what is its power impact?

The ADS7890IPFBRG4 enters nap mode automatically after conversion completion and remains there until the 8th SCLK rising edge. In this state, supply current drops to 2–3 mA (vs. 9–12 mA active), reducing power dissipation to ~10 mW. This feature is documented in the Power Supply Requirements table (page 4) and enables energy-efficient burst-mode sampling in portable instrumentation.

What digital interface protocols does the ADS7890IPFBRG4 support, and how are they selected?

The ADS7890IPFBRG4 supports both SPI and DSP serial interfaces. Interface selection is determined by control signal usage: SPI uses CS and SCLK only (FS held high); DSP uses CS, SCLK, and FS. Timing diagrams (Figures 1 and 2) and Table 1 confirm MSB-first straight binary output in both modes - no hardware configuration or register setting is required.

What is the significance of the −IN pin's ±0.2 V range in the ADS7890IPFBRG4?

The −IN pin's ±0.2 V range enables common-mode noise rejection and ground voltage mismatch compensation between sensor and ADC. As stated in the DESCRIPTION section (page 2), this design allows cancellation of low-frequency interference while preserving DC-coupled signal integrity - a key enabler for precision measurements in noisy industrial environments.