Texas Instruments ADC3681IRSBT

Overview

ADC3681IRSBT from Texas Instruments is an 18-bit, dual-channel, 10-MSPS ultra-low-noise, low-power analog-to-digital converter optimized for high-precision data acquisition in industrial and instrumentation systems. It delivers -151.7 dBFS/Hz noise spectral density, ±0.7 LSB typical DNL, and 84.7 dBFS SNR at 1.1 MHz input - enabling high-fidelity digitization of low-amplitude signals in source measurement units and power quality analyzers.

For engineers reviewing the ADC3681IRSBT datasheet, ADC3681IRSBT pinout, ADC3681IRSBT application, or ADC3681IRSBT equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, application-specific implementation value, and two confirmed alternative options with documented functional and parametric differences.

Technical Context

The ADC3681IRSBT implements a pipelined SAR architecture with on-chip digital decimation filters (2×–32×), a 32-bit numerically controlled oscillator (NCO), and configurable serial LVDS output (1-/2-/½-wire modes). Its 1-clock-cycle latency in 1-wire SLVDS mode supports tight control-loop timing, while the 900 MHz analog input bandwidth enables direct RF sampling up to IF frequencies.

It operates from dual 1.8 V supplies (AVDD, IOVDD), supports external 1.6 V or internal reference, and features programmable power scaling: 53 mW per channel at 10 MSPS. The device uses differential analog inputs (AINP/M, BINP/M), a dedicated VCM output (0.95 V), and includes hardware SYNC/PDN and SPI-configurable reset for deterministic system synchronization.

Key Specifications

Pinout & Package

ADC3681IRSBT is housed in a 40-pin VQFN package (RSB variant), 5.0 mm × 5.0 mm, with exposed thermal pad. Pin functions are validated per TI SBAS872B Rev B (October 2022).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-resolution, low-power dual-channel ADC applications.

Compared with ADC3681IRSBT, ADC3682IRSBT offers higher speed with identical feature set and pin compatibility, whereas ADS9224RIRTCR trades speed, on-chip processing, and interface complexity for lower power and smaller footprint - making it suitable only for non-coherent, low-update-rate sensing.

Availability

ADC3681IRSBT is available at Aetrix Electronics and suitable for source measurement units, power quality analyzers, and software-defined radio front-ends requiring stable component supply, long-term production continuity, and guaranteed industrial temperature performance.

Supply support for ADC3681IRSBT 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 high-performance data converters and signal chain solutions.

The ADC368x family was designed specifically for ultra-low-noise, low-power, high-precision dual-channel digitization in industrial test equipment, communications infrastructure, and real-time control systems - prioritizing spectral purity, deterministic latency, and flexible digital interface options.

FAQ

What is the maximum sampling rate supported by ADC3681IRSBT?

The ADC3681IRSBT supports a maximum sampling rate of 10 MSPS, as specified in the device comparison table and electrical characteristics section of the SBAS872B datasheet. This rate is fixed for the ADC3681 variant - unlike the pin-compatible ADC3682 (25 MSPS) and ADC3683 (65 MSPS) in the same family. Operation above 10 MSPS is not guaranteed and may violate AC specifications.

Does ADC3681IRSBT support internal voltage reference operation?

Yes, ADC3681IRSBT supports internal reference operation with a nominal 1.6 V output. When enabled, it achieves ±0.64% gain error and 109 ppm/°C gain drift - verified in Section 6.6 DC Specifications of the datasheet. External 1.6 V reference yields tighter ±0.9% gain error but requires additional circuitry.

What is the latency of ADC3681IRSBT in 1-wire SLVDS mode?

In 1-wire SLVDS mode, ADC3681IRSBT achieves 1 ADC clock cycle latency from analog input sampling to valid digital output - confirmed in Table 6-14 (Timing Requirements) of SBAS872B. This applies to both channels simultaneously and is independent of decimation settings, making it ideal for time-critical control applications.

Can ADC3681IRSBT be used with single-ended clock inputs?

Yes, ADC3681IRSBT supports single-ended clock inputs via configuration through its SPI interface. The datasheet states that enabling this mode reduces analog supply current by 0.7 mA (Section 6.5), and timing parameters remain valid per Table 6-14 - though jitter performance may degrade compared to differential clocking.

What package type and dimensions does ADC3681IRSBT use?

ADC3681IRSBT uses a 40-pin VQFN package (Texas Instruments RSB designation), measuring 5.0 mm × 5.0 mm with an exposed thermal pad on the underside. This is explicitly stated in the "Package Information" section and Figure 5-1 (Pin Configuration) of SBAS872B Rev B.