Texas Instruments ADS7947SRTER

Overview

ADS7947SRTER from Texas Instruments is a 12-bit, 2.1-MSPS pseudo-differential successive approximation register (SAR) analog-to-digital converter with integrated 2-channel analog multiplexer, SPI interface, and auto power-down. It operates from 2.7 V to 5.5 V AVDD and 1.65 V to AVDD DVDD, delivers 72 dB SNR and ±0.3 LSB INL, and targets high-precision data acquisition in space-constrained industrial systems.

For engineers reviewing the ADS7947SRTER datasheet, ADS7947SRTER pinout, ADS7947SRTER application, or ADS7947SRTER equivalent, key selection criteria include its 12-bit resolution at 2.1 MSPS throughput, ultra-low 7.5 mW active power at 2 MSPS, extended –40°C to +125°C temperature rating, and WQFN-16 package compatibility with battery-powered and optical networking signal chains.

Technical Context

The ADS7947SRTER implements a true SAR architecture with internal sample-and-hold, supporting unipolar pseudo-differential input pairs (AIN0P/AIN0N, AIN1P/AIN1N) and channel selection via CH SEL. Its conversion timing is synchronized to an external SPI clock (up to 34 MHz), with fixed 13.5-SCLK conversion time in standard 16-clock frame mode.

It features dual independent ground references (REFGND and GND), separate analog (AVDD) and digital (DVDD) supplies, and a dedicated reference input (REF) decoupled to REFGND. Power-down is triggered by PDEN high at CS rising edge, enabling 0.16 mW standby at 20 kSPS.

Key Specifications

Pinout & Package

ADS7947SRTER is housed in a 3.00 mm × 3.00 mm, 16-pin WQFN package with wettable flanks, optimized for automated optical inspection (AOI) and thermal performance (R_θJB = 19.2°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog-to-digital conversion applications.

Compared with ADS7948SRTER, ADS7947SRTER provides 2 additional bits of resolution and 11 dB higher SNR at the cost of 0.47 MSPS lower peak throughput; versus ADS8860IDRCT, it trades 4-bit resolution for integrated dual-channel mux, 2.1× higher speed, and 3.0 mW lower power at comparable sample rates.

Availability

ADS7947SRTER is available at Aetrix Electronics and suitable for communication systems, optical networking modules, and medical instrumentation requiring stable component supply across extended temperature and long production lifecycles.

Supply support for ADS7947SRTER 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, embedded processing, and connectivity technologies, with decades of expertise in precision data converters and industrial-grade IC design.

The ADS794x family was engineered for ultra-low-power, high-throughput data acquisition in thermally constrained and battery-sensitive applications-including portable test equipment, optical transceivers, and distributed sensor nodes-where small size and wide temperature operation are non-negotiable.

FAQ

What is the maximum achievable sample rate for ADS7947SRTER, and under what conditions?

The ADS7947SRTER achieves a maximum sample rate of 2.1 MSPS when operated with a 34-MHz SCLK and a short 13.5-clock data frame. This mode maintains full 12-bit performance and is distinct from the standard 2-MSPS 16-clock frame operation. The 2.1-MSPS rate requires precise timing control of CS and SCLK edges as specified in the timing diagram (Figure 1) and is validated across the full –40°C to +125°C temperature range.

Does ADS7947SRTER support true differential input, or only pseudo-differential?

The ADS7947SRTER supports pseudo-differential input only: each channel uses one dedicated positive input (AIN0P or AIN1P) and one shared negative input (AIN0N or AIN1N) with a limited ±0.2 V allowable swing. AIN0N and AIN1N may be grounded to configure single-ended operation. It does not support true fully differential inputs (e.g., AIN0P/AIN0N with symmetrical ±VREF swing), as confirmed by the absolute input range specifications and functional description in Section 3 of SLAS708A.

How does the power-down feature of ADS7947SRTER operate, and what is its lowest quiescent current?

The ADS7947SRTER enters power-down mode when PDEN is high at the rising edge of CS. In this state, AVDD supply current drops to 2.5 µA (static) or 550 µA (dynamic with 34-MHz SCLK), and total power consumption falls to 0.16 mW at 20 kSPS. Power-up time is guaranteed at ≤1 µs. This behavior is explicitly characterized in Section 7.5 (Electrical Characteristics: ADS7947) and Figure 45 of the datasheet.

Can ADS7947SRTER interface directly with a 1.8-V microcontroller SPI port?

Yes, ADS7947SRTER supports direct SPI interfacing with 1.8-V microcontrollers: DVDD may be supplied from 1.65 V to AVDD, and logic thresholds are defined as VIH = 0.7×DVDD and VIL = 0.3×DVDD. At DVDD = 1.8 V, VIH = 1.26 V and VIL = 0.54 V-fully compatible with standard 1.8-V CMOS I/O. SDO output levels (VOH/VOL) are also specified for 1.8-V operation in Section 7.5.

What is the purpose of the REFGND pin on ADS7947SRTER, and how should it be connected?

The REFGND pin on ADS7947SRTER provides a dedicated, low-noise return path for the external reference voltage applied to the REF pin. It must be shorted to the analog ground plane with minimal trace length and not shared with digital or power ground returns. This separation prevents digital switching noise from modulating the reference voltage, which is essential to achieving the specified 72 dB SNR and ±0.3 LSB INL performance.