Texas Instruments ADS7279IRSAR

Overview

ADS7279IRSAR from Texas Instruments is a low-power, 14-bit, 1-MSPS successive approximation register (SAR) analog-to-digital converter with unipolar input range (0 V to V_REF), SPI/DSP-compatible serial interface, and built-in conversion clock. It operates from 2.7 V to 5.5 V analog supply and delivers ±0.4 LSB typical INL/DNL, 85.9 dB SNR at 10 kHz, and 105.3 dB SFDR - optimized for high-precision transducer and industrial data acquisition systems.

For engineers reviewing the ADS7279IRSAR datasheet, ADS7279IRSAR pinout, ADS7279IRSAR application, or ADS7279IRSAR equivalent, key selection considerations include its 4 × 4 mm QFN-16 package, dual power supply support (+VA and +VBD), programmable EOC/INT polarity, global CONVST trigger independent of CS, and daisy-chain capability for multi-ADC systems.

Technical Context

The ADS7279IRSAR implements a capacitor-based SAR architecture with inherent sample-and-hold, supporting both manual and auto-triggered conversion modes. Its internal 21–24.5 MHz conversion clock eliminates external timing components, while the SPI-compatible serial interface supports up to 50 MHz SCLK and configurable status output (EOC/INT/CDI) with programmable polarity.

It features three power-down modes - Deep Power-Down (0.004 µA), Nap (0.3 µA), and Auto Nap - enabling dynamic power management in battery-sensitive applications. The device accepts an external reference (0.3 V to +VA) and supports unipolar differential input (+IN/–IN), with –IN typically grounded for single-ended operation.

Key Specifications

Pinout & Package

The ADS7279IRSAR is housed in a 4 × 4 mm, 16-pin QFN package (RSA) with exposed thermal pad internally connected to substrate. Pin 1 is REF+ (REFIN); pin 16 is REF–; pins 13 and 14 are +IN and –IN respectively; pin 3 is CONVST; pin 4 is EOC/INT/CDI; pin 5 is FS/CS; pins 6 and 7 are SDI and SDO; pin 9 is SCLK; pins 11 and 10 are +VA and +VBD; pins 15 and 8 are AGND and BDGND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 14-bit SAR ADC applications.

Compared with ADS7279IPWR, the ADS7279IRSAR offers superior thermal performance and smaller footprint; compared with ADS8329IRHBT, it trades 2 bits of resolution for 2× throughput, integrated clocking, and lower total system power in 14-bit industrial sensing roles.

Availability

ADS7279IRSAR is available at Aetrix Electronics and suitable for industrial process control, medical instrumentation, and transducer interface applications requiring stable component supply, long-term production continuity, and guaranteed industrial temperature grade (–40°C to +85°C).

Supply support for ADS7279IRSAR 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 ADS7279IRSAR belongs to TI's low-power, high-speed SAR ADC family targeting industrial sensing and data acquisition. It was engineered to deliver 14-bit accuracy at 1 MSPS with minimal external components and robust operation across harsh environments.

FAQ

What is the maximum sampling rate of the ADS7279IRSAR and under what supply conditions?

The ADS7279IRSAR achieves 1 MSPS maximum sampling rate when the analog supply (+VA) is between 3 V and 5.5 V. At 2.7 V ≤ +VA < 3 V, the maximum rate drops to 900 kSPS due to internal clock limitations. This behavior is specified in the Electrical Characteristics table and confirmed across both 5 V and 1.8 V timing sections of the datasheet.

Does the ADS7279IRSAR require an external reference voltage, and what are its valid input ranges?

Yes, the ADS7279IRSAR requires an external reference applied between REF+ and REF–. Valid V_REF ranges are 0.3 V to +VA, with tighter constraints depending on sample rate: for f_SAMPLE > 500 kSPS and +VA ≥ 3 V, V_REF must be 2.475 V to 3 V; for +VA = 5 V, V_REF is typically 5 V. REF– must be connected to AGND via a dedicated via.

How does the CONVST pin function in the ADS7279IRSAR, and is it dependent on the CS signal?

The CONVST pin initiates conversion on its rising edge and freezes the sample-and-hold circuit. Critically, CONVST operates independently of FS/CS - enabling global synchronization across multiple ADS7279IRSAR devices without requiring coordinated chip-select timing. This is explicitly stated in the device description and timing diagrams.

What power-down modes does the ADS7279IRSAR support, and what are their typical current draws?

The ADS7279IRSAR supports three power-down modes: Deep Power-Down (0.004 µA typical), Nap (0.3 µA typical), and Auto Nap (0.3 µA typical). Deep Power-Down disables all circuitry except wake-up logic; Nap retains register state; Auto Nap automatically enters Nap after conversion completion. All values are measured at +VA = 3 V per the Electrical Characteristics table.

Can the ADS7279IRSAR be used in daisy-chain configuration, and how is it implemented?

Yes, the ADS7279IRSAR supports daisy-chain operation using the EOC/INT/CDI pin as chain data input. In this mode, SDO of one device connects to SDI of the next, with shared SCLK and FS/CS. Data from all devices shifts out sequentially on a single SDO line, reducing SPI bus resource usage. This capability is documented in the Features section and Figure 5 timing diagram.