Texas Instruments ADS7961SDBT

Overview

ADS7961SDBT from Texas Instruments is a 12-bit, 16-channel, single-ended SAR analog-to-digital converter with 1-MSPS sample rate, zero-latency operation, and 20-MHz SPI-compatible serial interface. It features two software-selectable unipolar input ranges (0 to VREF and 0 to 2×VREF), programmable per-channel high/low alarm thresholds, and operates from 2.7–5.25 V analog supply. It is used in high-speed PLC data acquisition systems requiring multichannel monitoring with real-time alarm triggering.

For engineers reviewing the ADS7961SDBT datasheet, ADS7961SDBT pinout, ADS7961SDBT application, or ADS7961SDBT equivalent, key selection criteria include channel count (16), resolution (12-bit), sampling speed (1 MSPS), alarm functionality per channel, GPIO configurability, and TSSOP-38 package compatibility with other ADS79xx family members.

Technical Context

The ADS7961SDBT implements a capacitor-based SAR architecture with integrated sample-and-hold, enabling zero-latency conversion and deterministic timing. Its multiplexer supports 16 single-ended analog inputs (Ch0–Ch15), routed through MXO to AINP/AINM for conversion, with independent gain control via external PGA or buffer (e.g., THS4031).

It supports both auto-sequencing (Auto-1/Auto-2 modes) and manual channel selection via SDI commands, and uses CS falling edge for sampling initiation. The device includes four configurable GPIOs (GPIO0–GPIO3) - used for alarm outputs (high/low), range selection, and power-down - all accessible in the TSSOP-38 package.

Key Specifications

Pinout & Package

The ADS7961SDBT is housed in a 38-pin TSSOP package (7.80 mm × 4.40 mm) with exposed thermal pad. All pins are electrically validated per TI SLAS605C Rev C datasheet, including NC pin grounding requirements.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel SAR ADC applications.

Compared with ADS7960SDBT, the ADS7961SDBT adds four extra analog inputs without increasing package size or interface complexity; versus ADS8688IPWR, it trades resolution and integrated reference for higher channel count, lower latency, and hardware alarm autonomy - making it optimal for dense, real-time industrial monitoring.

Availability

ADS7961SDBT is available at Aetrix Electronics and suitable for PLC analog input modules, optical line card telemetry, medical patient monitors, digital power supply controllers, and high-speed closed-loop systems requiring stable component supply and long-term industrial lifecycle support.

Supply support for ADS7961SDBT 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 industrial-grade IC design.

The ADS79xx product line was engineered specifically for high-channel-count, real-time industrial data acquisition - emphasizing zero-latency conversion, per-channel alarm autonomy, and flexible power/interface scalability across 8-/10-/12-bit variants.

FAQ

What is the maximum clock frequency supported by the ADS7961SDBT serial interface?

The ADS7961SDBT supports a maximum SCLK frequency of 20 MHz, enabling full 12-bit word transfer in under 1.2 µs. This timing aligns with its 1-MSPS sample rate specification and ensures reliable communication with high-speed microcontrollers or FPGAs. The ADS7961SDBT datasheet specifies setup/hold timing relative to this 20-MHz limit, and exceeding it may cause data corruption or missed conversions.

Does the ADS7961SDBT require an external reference voltage, and what is the recommended part?

Yes, the ADS7961SDBT requires an external precision reference applied to REFP/REFM pins. Texas Instruments recommends REF5025 (2.5-V, 3-ppm/°C drift) for optimal performance, as cited in the ADS7961SDBT application diagrams and electrical characteristics tables. Using REF5025 ensures the specified ±0.99 LSB differential nonlinearity and maintains accuracy across temperature in industrial environments.

How many GPIOs are available on the ADS7961SDBT, and what functions do they serve?

The ADS7961SDBT provides four GPIOs (GPIO0–GPIO3) in its TSSOP-38 package. GPIO0 serves as high-alarm output, GPIO1 as low-alarm output, GPIO2 selects input range (0 to VREF or 0 to 2×VREF), and GPIO3 is an active-low power-down input. These are fully documented in the Pin Functions table of the ADS7961SDBT datasheet and enable hardware-level system responsiveness without host intervention.

Can the ADS7961SDBT operate with different analog and I/O supply voltages?

Yes, the ADS7961SDBT supports independent analog and digital supplies: +VA (2.7–5.25 V) powers the ADC core and mux, while +VBD (1.7–5.25 V) powers the SPI interface. This allows interfacing with 1.8-V microcontrollers while running the analog section at 5 V for improved SNR - a capability verified in the ADS7961SDBT recommended operating conditions table and widely used in mixed-voltage industrial designs.

What is the purpose of the MXO pin on the ADS7961SDBT, and how is it used in system design?

The MXO (Multiplexer Output) pin on the ADS7961SDBT provides access to the internal analog multiplexer output before the SAR core, allowing external signal conditioning - such as high-input-impedance buffering (e.g., THS4031) or programmable-gain amplification - to be inserted between the mux and AINP. This architecture preserves ADC accuracy while enabling flexible front-end design, as explicitly shown in the ADS7961SDBT functional block diagram and application schematics.