Texas Instruments ADS7958SDBTR

Overview

ADS7958SDBTR from Texas Instruments is a 8-bit, 4-channel, single-ended SAR analog-to-digital converter with 1-MSPS sample rate, zero-latency operation, and 20-MHz serial interface. It features two software-selectable unipolar input ranges (0 to VREF and 0 to 2×VREF), programmable per-channel alarm thresholds, and operates from 2.7–5.25 V analog supply. Used in PLC analog input modules for real-time sensor monitoring.

For engineers reviewing the ADS7958SDBTR datasheet, ADS7958SDBTR pinout, ADS7958SDBTR application, or ADS7958SDBTR equivalent, key selection considerations include its 4-channel count, 8-bit resolution, TSSOP-30 package footprint, GPIO0–GPIO3 configurability (TSSOP variant), and support for auto/manual channel sequencing in industrial data acquisition systems.

Technical Context

The ADS7958SDBTR implements a capacitor-based SAR architecture with integrated sample-and-hold, enabling zero-latency conversion. Its serial interface uses active-low CS, SCLK, SDI, and SDO signals compatible with standard microcontrollers and DSPs without glue logic.

It supports dual input ranges via the RANGE pin (GPIO2), provides two programmable alarm levels per channel (high/low), and allows either automatic preselected channel sequencing or manual channel selection per conversion cycle - all configurable via SPI-like serial commands.

Key Specifications

Pinout & Package

ADS7958SDBTR is housed in a 30-pin TSSOP (DBT) package measuring 7.80 mm × 4.40 mm, with exposed thermal pad (not electrically connected). Pin functions are validated per TI SLAS605C Rev C, Table 7 (TSSOP Packages).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7951SDBTR and ADS7954SDBTR, the ADS7958SDBTR offers optimal balance of channel count, resolution, and power for cost-sensitive industrial monitoring - delivering sufficient accuracy for 4–20 mA loop diagnostics while minimizing BOM and thermal overhead.

Availability

ADS7958SDBTR is available at Aetrix Electronics and suitable for PLC analog input modules, optical line card telemetry, and medical patient monitor front-ends requiring stable component supply across extended production lifecycles.

Supply support for ADS7958SDBTR 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 and embedded processing technologies with over 50 years of innovation in data conversion and industrial interface solutions.

The ADS79xx family was designed specifically for high-speed, multi-channel industrial data acquisition - emphasizing pin compatibility across resolutions and channel counts to simplify platform scaling and reduce qualification effort.

FAQ

What is the maximum supported serial clock frequency for ADS7958SDBTR?

The ADS7958SDBTR supports a 20-MHz SCLK frequency, enabling full 8-bit conversion and data readout within 16 clock cycles. This timing aligns with the device's 1-MSPS sample rate specification and ensures reliable communication with standard microcontrollers and FPGAs without requiring custom timing logic. The ADS7958SDBTR datasheet specifies t_su1 and t_su2 setup/hold times referenced to this 20-MHz maximum.

Does ADS7958SDBTR include an internal voltage reference?

No, the ADS7958SDBTR does not integrate an internal voltage reference. It requires an external reference applied to the REFP and REFM pins, such as the REF5025 (2.5 V ±0.1 V), to define its full-scale input range. This architecture allows designers to select reference accuracy, temperature drift, and noise performance independently - critical for applications like precision current loop monitoring where reference stability directly impacts system accuracy.

How many GPIOs are available on ADS7958SDBTR and what are their functions?

The ADS7958SDBTR provides four individually configurable GPIOs (GPIO0–GPIO3) in its 30-pin TSSOP package. GPIO2 serves as RANGE input to select 0–VREF or 0–2×VREF input range; GPIO3 acts as active-low PD input for power-down mode; GPIO0 and GPIO1 function as programmable alarm outputs (high/low threshold indicators). These are documented in TI SLAS605C Table 7 for TSSOP packages.

Can ADS7958SDBTR operate with separate analog and digital supply voltages?

Yes, the ADS7958SDBTR supports independent analog (+VA) and digital I/O (+VBD) supplies. +VA ranges from 2.7 V to 5.25 V for the ADC core and reference circuitry, while +VBD operates from 1.7 V to 5.25 V for the serial interface and GPIOs. This separation allows interfacing with low-voltage FPGAs or MCUs (e.g., 1.8 V) while maintaining high-precision analog performance powered from a clean 3.3 V or 5 V rail - a key advantage in mixed-signal industrial systems.

What is the purpose of the MXO pin on ADS7958SDBTR?

The MXO (Multiplexer Output) pin on ADS7958SDBTR is an analog output that delivers the selected channel's signal after internal multiplexing but before ADC conversion. It enables external signal conditioning - such as filtering, buffering with THS4031, or gain adjustment - immediately upstream of the ADC core. This architecture improves noise immunity and allows designers to implement anti-aliasing filters matched to specific channel bandwidth requirements, which is essential in multi-sensor monitoring applications.