Texas Instruments ADS7949SRTET

Overview

ADS7949SRTET from Texas Instruments is an 8-bit, dual-channel, pseudo-differential successive approximation register (SAR) analog-to-digital converter with 3 MSPS throughput, 72 dB SNR (min), and operation over –40°C to +125°C. It integrates a 2-channel input multiplexer, SPI interface, and auto power-down, targeting high-speed data acquisition in space-constrained battery-powered systems.

For engineers reviewing the ADS7949SRTET datasheet, ADS7949SRTET pinout, ADS7949SRTET application, or ADS7949SRTET equivalent, key selection criteria include its 3-MSPS sample rate at 8-bit resolution, 3-mm × 3-mm WQFN-16 package, 2.7–5.5 V analog supply range, and pseudo-differential input architecture supporting unipolar signal conditioning.

Technical Context

The ADS7949SRTET implements a SAR ADC core with integrated 2:1 analog multiplexer, enabling channel selection via the CH SEL digital input. Its conversion timing uses an 8.5-SCLK frame for full 3-MSPS operation, with aperture jitter of 10 ps and acquisition time of 80 ns - optimized for high-fidelity sampling of fast transient signals.

It supports independent analog (AVDD) and digital (DVDD) supplies, where DVDD operates down to 1.65 V while maintaining CMOS logic compatibility. Power management includes dynamic current scaling: 7.5 mW at 2 MSPS, dropping to 0.16 mW at 20 kSPS via PDEN-controlled auto power-down.

Key Specifications

Pinout & Package

The ADS7949SRTET is housed in a 3.0 mm × 3.0 mm, 16-pin WQFN package with wettable flanks and thermal pad. Pin 1 is marked by a dot; pins 9 and 10 are NC and must be externally shorted to GND per TI recommendation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel SAR ADC applications.

Compared with ADS7948SRTET and ADS8661IPWR, the ADS7949SRTET provides the highest throughput (3 MSPS) in its pin-compatible family and uniquely supports dual-channel pseudo-differential acquisition in a 3-mm × 3-mm package - making it optimal for space-limited, multi-signal monitoring systems requiring speed over ultimate precision.

Availability

ADS7949SRTET is available at Aetrix Electronics and suitable for communication systems, optical networking modules, and battery-powered medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADS7949SRTET 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 low-power design.

The ADS794x product line was engineered for high-speed, low-power data acquisition in thermally demanding environments - targeting applications where size, power efficiency, and robustness across –40°C to +125°C are non-negotiable.

FAQ

What is the maximum sample rate of the ADS7949SRTET and under what conditions is it achieved?

The ADS7949SRTET achieves a maximum sample rate of 3 MSPS when operated with a 34-MHz SCLK and a shortened 8.5-clock data frame. This rate is specified under recommended operating conditions: AVDD = 2.7 V to 5.5 V, DVDD = 1.65 V to AVDD, and TA = –40°C to +125°C. At 2 MSPS using the standard 16-clock frame, the ADS7949SRTET maintains full 8-bit performance with no degradation in INL or SNR. The ADS7949SRTET's timing is validated per TI's SLAS708A datasheet Section 7.8.

Does the ADS7949SRTET support true differential input, or is it pseudo-differential?

ADS7949SRTET supports pseudo-differential input only. Each channel (AIN0 and AIN1) accepts a positive input (AINxP) referenced against a dedicated negative input (AINxN), where AINxN is constrained to ±0.2 V and may be grounded. It does not support fully differential signaling (e.g., AINxP and AINxN swinging symmetrically around common-mode voltage). This architecture simplifies sensor interfacing for unipolar sources like RTDs or bridge amplifiers while retaining common-mode rejection. The ADS7949SRTET datasheet explicitly defines this as "unipolar, pseudo-differential" input topology.

How does the power-down feature of the ADS7949SRTET operate, and what is its lowest quiescent current?

The ADS7949SRTET enters power-down mode when PDEN is high at the rising edge of CS, reducing AVDD supply current to 2.5 µA (static) with SCLK inactive. Dynamic power-down current is 550 µA when SCLK remains active at 34 MHz. At 20 kSPS, total power drops to 0.16 mW - verified in Section 7.7 of the ADS7949SRTET datasheet. This feature is fully automatic and requires no register writes, making it ideal for burst-mode acquisition in battery-powered ADS7949SRTET applications.

Can the ADS7949SRTET interface directly with a 1.8-V microcontroller SPI port?

Yes - the ADS7949SRTET supports DVDD from 1.65 V to AVDD, and its SPI interface meets CMOS logic thresholds: VIH = 0.7 × DVDD and VIL = 0.3 × DVDD. With DVDD = 1.8 V, VIH = 1.26 V and VIL = 0.54 V, ensuring reliable communication with 1.8-V MCUs without level shifters. The SDO output drives to DVDD – 0.2 V (VOH) and 0.4 V (VOL) under 200 µA load, matching standard 1.8-V I/O specifications. This capability is confirmed in Section 7.5 of the ADS7949SRTET electrical characteristics table.

What is the guaranteed integral nonlinearity (INL) specification for the ADS7949SRTET across temperature and supply voltage?

The ADS7949SRTET guarantees INL of ±0.3 LSB maximum across the full operating range: –40°C to +125°C, AVDD = 2.7 V to 5.5 V, and VREF = 2.5 V to AVDD. This value is tested and specified in Section 7.7 of the datasheet and is independent of sample rate. Typical INL is ±0.06 LSB. The specification ensures monotonicity and ≤0.12% full-scale error in industrial and automotive environments where the ADS7949SRTET is deployed.