Texas Instruments ADS7953SDBT

Overview

ADS7953SDBT 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 integrated programmable gain amplifier (PGA) input stage. It features dual software-selectable unipolar input ranges (0 to VREF and 0 to 2×VREF), two per-channel alarm thresholds, and four GPIOs in its 30-pin TSSOP package. It is used in high-speed PLC analog input modules requiring channel sequencing and real-time threshold monitoring.

For engineers reviewing the ADS7953SDBT datasheet, ADS7953SDBT pinout, ADS7953SDBT application, or ADS7953SDBT equivalent, key selection considerations include its 16-channel count, 12-bit resolution at 1 MSPS, TSSOP-30 package compatibility, GPIO-configurable alarm outputs, and support for auto/manual channel sequencing without external logic.

Technical Context

The ADS7953SDBT implements a capacitor-based SAR architecture with inherent sample-and-hold, accepting analog supply voltages from 2.7 V to 5.25 V and I/O supply from 1.7 V to 5.25 V. Its serial interface uses active-low CS, SCLK, SDI, and SDO signals operating up to 20 MHz, with sampling triggered on the falling edge of CS.

It supports both auto-sequencing across preselected channels and manual channel selection per conversion cycle. Input signal routing includes a high-impedance PGA (or non-inverting buffer) path via AINP/AINM, and a multiplexer output (MXO) for buffered analog monitoring. Each of its 16 analog inputs (Ch0–Ch15) supports independent alarm level programming.

Key Specifications

Pinout & Package

The ADS7953SDBT is housed in a 30-pin TSSOP package (DBT suffix), with exposed thermal pad. Pin functions are validated per TI SLAS605C Rev C (July 2018), including dedicated analog inputs (Ch0–Ch15), reference pins (REFP/REFM), serial interface (CS/SCLK/SDI/SDO), GPIOs (GPIO0–GPIO3), and power domains (+VA/AGND/+VBD/BDGND).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7952SDBT, the ADS7953SDBT adds four more analog inputs while retaining identical pinout and feature set; versus ADS8688IPWR, it trades resolution and integrated reference for channel count, alarm hardware, and lower power - making it optimal for dense, responsive industrial data acquisition.

Availability

ADS7953SDBT is available at Aetrix Electronics and suitable for PLC analog input modules, optical line card telemetry, and medical instrumentation requiring stable component supply, long-term manufacturability, and consistent electrical performance across production lots.

Supply support for ADS7953SDBT 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 and embedded processing technologies, with leadership in precision data converters and industrial interface solutions.

The ADS79xx family was designed for high-channel-count, real-time industrial data acquisition - emphasizing zero-latency conversion, hardware alarm triggering, and flexible supply/interface compatibility to simplify system-level design.

FAQ

What is the maximum sample rate of the ADS7953SDBT?

The ADS7953SDBT achieves a maximum sample rate of 1 million samples per second (1 MSPS). This rate is sustained across all 16 channels when using auto-sequencing mode, with each conversion completing within 1 µs. The device maintains this performance under recommended operating conditions: +VA = 2.7 V to 5.25 V, +VBD = 1.7 V to 5.25 V, and ambient temperature from –40°C to +125°C. The ADS7953SDBT delivers this speed without pipeline latency, making it suitable for time-critical closed-loop control applications.

Does the ADS7953SDBT require an external reference voltage?

Yes, the ADS7953SDBT requires an external reference voltage applied to the REFP and REFM pins. It does not include an internal reference. The device supports two software-selectable input ranges: 0 to VREF and 0 to 2×VREF, where VREF is the voltage difference between REFP and REFM. A precision reference such as the REF5025 (2.5 V ±0.1 V) is commonly used. The ADS7953SDBT specifies reference input resistance as 100 kΩ typical, and reference voltage must remain stable during conversion to maintain accuracy. The ADS7953SDBT does not regulate or buffer the reference internally.

How many GPIOs does the ADS7953SDBT provide, and what are their functions?

The ADS7953SDBT provides four individually configurable GPIOs (GPIO0–GPIO3) in its TSSOP-30 package. GPIO2 serves as the Range select input (high = 0 to 2×VREF, low = 0 to VREF); GPIO3 is the active-low power-down (PD) input; GPIO0 and GPIO1 function as active-high alarm outputs - GPIO0 for high-alarm and GPIO1 for low-alarm status per selected channel. These GPIOs are programmable via internal registers and retain configuration across power cycles. The ADS7953SDBT does not support bidirectional data transfer on these pins beyond their defined alarm/control roles.

What is the purpose of the MXO pin on the ADS7953SDBT?

The MXO (Multiplexer Output) pin on the ADS7953SDBT provides a buffered analog copy of the currently selected input channel - whether chosen manually or via auto-sequencing. It is not a converted digital output, but rather an analog voltage replica available for external oscilloscope monitoring, secondary signal conditioning, or verification without loading the primary signal path. The MXO output is driven by a high-impedance PGA or non-inverting buffer (e.g., THS4031-class stage), preserving signal integrity. This feature allows real-time analog visibility into the ADC's input selection state, and the ADS7953SDBT maintains MXO functionality regardless of conversion mode or alarm status.

Can the ADS7953SDBT operate with different analog and digital supply voltages?

Yes, the ADS7953SDBT supports independent analog and digital supplies: +VA (analog supply, 2.7 V to 5.25 V) and +VBD (I/O supply, 1.7 V to 5.25 V). This separation enables glueless interfacing with hosts operating at 1.8 V, 3.3 V, or 5 V logic levels while maintaining optimal analog performance. For example, +VA can be set to 5 V for maximum SNR, while +VBD is set to 1.8 V to match a low-power microcontroller's I/O domain. The ADS7953SDBT specifies that digital timing parameters (e.g., tSU1, tSU2) scale with +VBD, and all digital pins (CS, SCLK, SDI, SDO, GPIOs) are referenced to +VBD and BDGND - not +VA.