Texas Instruments ADS7891EVM

Overview

ADS7891EVM from Texas Instruments is an evaluation module designed to prototype and validate the ADS7891 14-bit, 3-MSPS parallel-output SAR analog-to-digital converter. It integrates on-board signal conditioning (THS4031 amplifier), a 2.5-V reference (REF1004-2.5), digital buffers (SN74AHC245), and address decoding (SN74AHC138) for direct interfacing with TMS320C5000/C6000 DSP starter kits.

For engineers reviewing the ADS7891EVM datasheet, ADS7891EVM pinout, ADS7891EVM application, or ADS7891EVM equivalent, this module supports rapid validation of high-speed data acquisition systems requiring 1-MHz AC performance, byte-mode 8-bit processor interfacing, and pseudo-differential analog input with ±200-mV negative input range.

Technical Context

The ADS7891EVM implements a complete analog front-end using the THS4031 inverting unity-gain buffer with 130-pF C0G input capacitor and 604-Ω series resistor to meet 1-MHz sine-wave AC specifications. Its reference subsystem allows selection among internal ADC reference, onboard REF1004-2.5, or external reference via P1 pin 20.

Digital interface flexibility is achieved through jumper-configurable memory-mapped control signals (RD, CONVST, RESET) using SN74AHC138 decoding across three address lines (A0–A2), while direct access to converter control (CS, BUSY, BYTE) and 14-bit data bus (D0–D13) is provided via J3 and P3 connectors.

Key Specifications

Availability

ADS7891EVM is available at Aetrix Electronics and suitable for high-speed data acquisition, DSP-based signal processing, and precision analog front-end prototyping requiring stable component supply and documented TI reference design validation.

Supply support for ADS7891EVM 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 company specializing in analog, embedded processing, and digital signal solutions for industrial, automotive, and communications applications.

The ADS7891EVM belongs to TI's precision data converter evaluation platform family, engineered to accelerate development of high-fidelity, real-time digitization systems using SAR ADCs in test, measurement, and DSP integration environments.

FAQ

What is the primary function of the ADS7891EVM?

The ADS7891EVM is an evaluation module built to characterize and prototype the ADS7891 14-bit, 3-MSPS parallel-output SAR analog-to-digital converter. It provides full signal chain support-including analog buffering (THS4031), reference generation (REF1004-2.5), digital buffering (SN74AHC245), and address decoding (SN74AHC138)-enabling immediate validation of the ADS7891EVM in real-world high-speed acquisition scenarios.

Which ADC does the ADS7891EVM specifically support?

The ADS7891EVM is configured for the ADS7891IPFBT: a 14-bit, 3-MSPS, parallel-output SAR ADC with pseudo-differential input, internal 2.5-V reference, and byte-mode operation. While the board shares layout with ADS7881EVM, ADS7891EVM uses R13 = 10 Ω and C16 = 1500 pF C0G per schematic revision notes to optimize for ADS7891EVM's resolution and speed requirements.

How is analog input conditioned on the ADS7891EVM?

The ADS7891EVM conditions analog input using the THS4031 configured as an inverting unity-gain buffer with 130-pF C0G capacitor and 604-Ω series resistor. This RC network-combined with the amplifier's low noise and fast settling-ensures the ADS7891EVM meets 1-MHz AC performance specs. The negative input is shorted, and +IN accepts signals via P1 pin 2 or SMA connector J2.

Can the ADS7891EVM interface directly with an 8-bit microcontroller?

Yes. The ADS7891EVM supports byte-mode operation via the BYTE pin (J3.7), allowing 8-bit processors to read the 14-bit result in two cycles. Data bits D0–D7 and D8–D13 are accessible on P3, and SN74AHC245 buffers ensure clean level-shifting and drive strength-making ADS7891EVM compatible with standard 8-bit bus architectures without external logic.

What power supplies are required to operate the ADS7891EVM?

The ADS7891EVM requires four independent supplies: +5.0 V for analog circuitry (AVCC), +3.3 V or +5.0 V for digital buffers (BVDD), and ±12 V for the THS4031 op-amp stage (VA/–VA). These may be applied via test points (TP10–TP14) or the 10-pin J1 power connector, with W5 jumper selecting +3.3VD or +5VD as BVDD source.