Texas Instruments ADS8405EVM

Overview

ADS8405EVM from Texas Instruments is a dedicated evaluation module for the ADS8405 16-bit, 1.25 MSPS parallel-output SAR analog-to-digital converter. It provides full signal chain support including on-board THS4031 input buffer, REF3040 voltage reference, digital bus transceivers (SN74AHC245), and address decoder (SN74AHC138), enabling rapid hardware validation and firmware development for high-precision data acquisition systems.

For engineers reviewing the ADS8405EVM datasheet, ADS8405EVM pinout, ADS8405EVM application, or ADS8405EVM equivalent, this module delivers ready-to-use analog front-end conditioning, memory-mappable parallel control interface, dual-supply op-amp support, flexible reference selection (internal/REF3040/user-supplied), and direct access to all ADC control signals via J3 connector.

Technical Context

The ADS8405EVM implements a complete test platform for the ADS8405 IC, featuring an inverting unity-gain THS4031 amplifier optimized for 100 kHz sine-wave performance, with RC filtering (6800 pF + 1 kΩ) matching the ADC's AC specifications. It supports ±12 V analog supply, +5 V analog section, and +3.3 V/+5 V digital supply - delivered either via test points (TP10–TP14) or 10-pin power connector J1.

Digital interfacing uses Samtec 0.1" headers (P1, P2, P3) and includes address decoding logic (SN74AHC138) to map RD, CONVST, and RESET to processor memory addresses A[2:0], while chip select (CS) is routed directly to J3.1 for external control or grounding.

Key Specifications

Availability

ADS8405EVM is available at Aetrix Electronics and suitable for high-precision data acquisition, industrial sensor interface, and embedded test equipment requiring stable component supply and full-spectrum evaluation capability for 16-bit SAR ADCs.

Supply support for ADS8405EVM 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and high-performance silicon solutions for industrial, automotive, and communications markets.

The ADS8405EVM belongs to TI's precision data converter evaluation platform family, designed specifically to accelerate prototyping and system-level validation of high-speed SAR ADCs in laboratory and engineering development environments.

FAQ

What is the primary function of the ADS8405EVM?

The ADS8405EVM is a dedicated evaluation module for the ADS8405 16-bit, 1.25 MSPS SAR analog-to-digital converter. It provides complete signal conditioning, reference generation, digital buffering, and memory-mappable parallel interface - enabling immediate hardware testing, firmware integration, and performance characterization without custom PCB design. The ADS8405EVM supports both lab validation and embedded software development workflows.

Which ADC does the ADS8405EVM support, and is it compatible with other variants?

The ADS8405EVM is explicitly designed for the ADS8405IPFBT (16-bit, 1.25 MSPS), but shares identical mechanical layout and circuit architecture with the ADS8401EVM and ADS8411EVM. All three modules use the same PCB footprint and interconnect scheme, allowing interchangeable use when the target ADC is socketed or soldered per BOM item U4(2). The ADS8405EVM is not a generic platform - its calibration and filtering are optimized for the ADS8405's timing and noise profile.

How is analog input conditioned on the ADS8405EVM?

The ADS8405EVM conditions analog input using the THS4031 operational amplifier configured as an inverting unity-gain buffer, with a 6800 pF capacitor and 1 kΩ series resistor forming a low-pass filter tuned to meet the ADS8405's 100 kHz ac performance specifications. The negative input is shorted to AGND via SJP3, and offset adjustment is enabled via 10 kΩ trimpot R25. This front-end is optimized for single-ended, ground-referenced signals applied at P1.2 or J2 center pin.

What reference voltage options does the ADS8405EVM provide?

The ADS8405EVM offers three reference configurations via solder jumpers SJP1–SJP4: (1) internal 4.096 V reference (factory default), (2) buffered REF3040 output (U3), or (3) user-supplied external reference via P1.20. The REF3040 (4.096 V, 50 ppm/°C) is populated on the board, and no external buffer is required since the ADS8405 integrates a reference input buffer - making U1 (OPA627) unpopulated by default.

Can the ADS8405EVM be used with DSP starter kits like C5000/C6000 DSK?

Yes - the ADS8405EVM is explicitly designed for interoperability with TI's 5-6K interface card, which mounts directly onto C5000 and C6000 Digital Signal Processor starter kits (DSK). Connectors P1, P2, and P3 plug into the 5-6K card's parallel interface, mapping the ADS8405EVM into the processor's memory space. Address lines A2–A0 and DC_CS are wired to P2, while RD, CONVST, and RESET are decoded via SN74AHC138 (U8) - enabling seamless firmware-driven control of the ADS8405EVM.