Texas Instruments ADS7958SRGET

Overview

ADS7958SRGET 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 high/low 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 ADS7958SRGET datasheet, ADS7958SRGET pinout, ADS7958SRGET application, or ADS7958SRGET equivalent, key selection considerations include its 4-channel count, 8-bit resolution, VQFN-24 package footprint, GPIO0 alarm output functionality, and compatibility with 1.7–5.25 V I/O supplies for microcontroller interfacing.

Technical Context

The ADS7958SRGET implements a capacitor-based SAR architecture with integrated sample-and-hold, sampling on the falling edge of CS and using SCLK for conversion timing and serial data transfer. Its auto-sequencing mode supports preselected channel cycling, while manual mode enables on-demand channel selection per conversion cycle.

It supports dual input ranges via the RANGE pin (GPIO2), delivers 47 MHz input bandwidth at 3 dB, and integrates four individually configurable GPIOs - though only GPIO0 is implemented in the VQFN-24 package as an active-high alarm output. Power-down current is 1 μA.

Key Specifications

Pinout & Package

ADS7958SRGET is housed in a 24-pin VQFN package (4.00 mm × 4.00 mm, 0.5 mm pitch) with wettable flanks, optimized for automated optical inspection and thermal performance in industrial PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit, multi-channel ADC applications.

Compared with ADS7954SRGET, ADS7958SRGET trades 2 bits of resolution for lower cost and reduced processing overhead in less demanding sensing tasks; versus ADS8320EB, it provides integrated channel multiplexing and alarm autonomy at the expense of absolute precision - making it optimal for cost-sensitive, multi-signal industrial monitoring.

Availability

ADS7958SRGET is available at Aetrix Electronics and suitable for PLC analog input modules, optical line card monitoring systems, and digital power supply telemetry requiring stable component supply across extended production lifecycles.

Supply support for ADS7958SRGET 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 interface solutions.

The ADS79xx family - including ADS7958SRGET - was designed specifically for high-speed, multi-channel data acquisition in programmable logic controllers, test equipment, and industrial automation systems where reliability, low latency, and flexible channel management are essential.

FAQ

What is the maximum serial clock frequency supported by the ADS7958SRGET?

The ADS7958SRGET supports a maximum SCLK frequency of 20 MHz, enabling full 8-bit conversion and data readout within 1 µs. This timing aligns with its 1-MSPS sample rate specification and ensures reliable communication with high-speed microcontrollers and FPGAs without requiring wait states. The ADS7958SRGET datasheet specifies setup/hold timing requirements relative to this 20 MHz limit.

Does the ADS7958SRGET require an external reference voltage?

Yes, the ADS7958SRGET requires an external reference voltage applied to the REFP pin, with REFM serving as its dedicated reference ground. The device is characterized for VREF = 2.5 V ±0.1 V, and supports two input ranges: 0 to VREF and 0 to 2×VREF. Internal reference is not provided; using REF5025 or similar precision references is recommended for metrology-grade accuracy in the ADS7958SRGET design.

How many GPIOs are available on the ADS7958SRGET in the VQFN-24 package?

The ADS7958SRGET in the VQFN-24 package implements only one GPIO: GPIO0, configured as an active-high alarm output. Unlike TSSOP variants which offer four GPIOs, the VQFN-24 variant dedicates pins to channel inputs and interface signals, leaving GPIO0 as the sole programmable I/O. This GPIO can be enabled to assert when any monitored channel exceeds its programmed high or low threshold.

Can the ADS7958SRGET operate with separate analog and digital supply voltages?

Yes, the ADS7958SRGET uses independent supply domains: +VA (2.7–5.25 V) powers the analog circuitry including the SAR core and multiplexer, while +VBD (1.7–5.25 V) powers the digital interface (SPI and GPIO). This separation minimizes digital switching noise coupling into the ADC conversion path and allows flexible power architecture design - for example, +VA = 5 V for analog headroom and +VBD = 3.3 V for MCU compatibility in the ADS7958SRGET implementation.

What is the purpose of the MXO pin on the ADS7958SRGET?

The MXO (Multiplexer Output) pin on the ADS7958SRGET is an analog output that presents the voltage of the currently selected input channel (Ch0–Ch3) after internal multiplexing but before ADC conversion. It is not a buffered output and is intended for diagnostic probing or optional external signal conditioning. In normal operation, MXO connects directly to the ADC's input stage, and its voltage reflects the sampled channel's instantaneous value at the moment of CS falling edge - a key timing node for understanding the ADS7958SRGET's zero-latency behavior.