Texas Instruments ADS7817EC

Overview

ADS7817EC from Texas Instruments is a 12-bit, 200kHz SAR analog-to-digital converter with fully differential high-impedance input, ±1 LSB integral linearity, 2.5V reference support, and MSOP-8 packaging - designed for precision transducer interfacing in battery-powered remote data acquisition systems.

For engineers reviewing the ADS7817EC datasheet, ADS7817EC pinout, ADS7817EC application, or ADS7817EC equivalent, key selection considerations include its micro-power operation (2.3mW at full rate), 3µA shutdown current, bipolar differential input architecture, and serial CMOS interface timing compatibility with low-power microcontrollers.

Technical Context

The ADS7817EC implements a capacitive redistribution successive approximation register (SAR) architecture on 0.6µm CMOS, enabling simultaneous sampling and conversion without external sample-and-hold circuitry. Its analog front-end supports true differential input with common-mode rejection of 80dB and AC-coupled rejection up to 5kHz.

Digital control uses a 3-wire synchronous serial interface: CS/SHDN initiates conversion and enables power-down mode when high; DCLOCK synchronizes 12-bit two's complement output on DOUT, with data valid on falling edges and null-bit preamble. Conversion time is fixed at 12 clock cycles, and acquisition requires 1.5 clock cycles.

Key Specifications

Pinout & Package

ADS7817EC is housed in an MSOP-8 package (3.0mm × 3.0mm, 0.65mm pitch), optimized for space-constrained PCB layouts in portable instrumentation and isolated sensor nodes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with ADS7817EC, ADS7816EB trades resolution and temperature stability for lower cost and power, while ADS8325IDRCT delivers superior accuracy at significantly higher power and layout cost - making ADS7817EC optimal for battery-operated, space-constrained 12-bit applications requiring guaranteed linearity across industrial temperature range.

Availability

ADS7817EC is available at Aetrix Electronics and suitable for transducer interface, battery-powered data loggers, isolated data acquisition, and AC motor current monitoring requiring stable component supply and long-term industrial lifecycle support.

Supply support for ADS7817EC 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 ADS7817EC belongs to TI's legacy precision SAR ADC product line, engineered specifically for high-fidelity signal acquisition in resource-constrained industrial and portable measurement systems.

FAQ

What is the maximum sampling rate supported by the ADS7817EC?

The ADS7817EC supports a maximum sampling rate of 200kHz, achieved with a 3.2MHz DCLOCK signal (16× oversampling). At this rate, the device completes conversion in 12 clock cycles (3.75µs) and requires 1.5 additional cycles for acquisition, delivering throughput consistent with real-time control loop requirements in motor drives and sensor fusion systems. The ADS7817EC maintains specified linearity and noise performance across the full 200kHz range.

Does the ADS7817EC require an external reference voltage?

Yes, the ADS7817EC requires an external reference voltage applied to the VREF pin. It operates with reference voltages from 0.1V to 2.5V, directly determining the full-scale input range (±VREF) and LSB size (2×VREF/4096). The ADS7817EC draws reference current that varies with sample rate and output code - up to 25µA at 200kHz and positive full-scale output - necessitating a low-impedance, well-bypassed reference source for optimal performance.

What package type is used for the ADS7817EC?

The ADS7817EC is packaged in an MSOP-8 (Mini Small Outline Package) with 3.0mm × 3.0mm body size and 0.65mm lead pitch. This compact surface-mount package provides thermal and electrical performance equivalent to SOIC-8 while occupying ~45% less PCB area - critical for wearable sensors, modular I/O cards, and space-limited industrial controllers where the ADS7817EC is commonly deployed.

How does the power-down mode function on the ADS7817EC?

The ADS7817EC enters full power-down mode when the CS/SHDN pin is driven high, reducing supply current to ≤3µA. This mode disables both analog and digital sections, eliminating dynamic power consumption while preserving pin states. In contrast, automatic power-down occurs after each conversion completes while CS remains low, reducing current to ~40µA. For lowest system power, the ADS7817EC should be cycled between active conversion and CS-high shutdown - a strategy validated in battery-life calculations for remote telemetry nodes using the ADS7817EC.

What is the input configuration supported by the ADS7817EC?

The ADS7817EC supports true fully differential bipolar input across pins +In and –In, accepting input spans from –VREF to +VREF with 80dB common-mode rejection. It also supports single-ended operation by fixing –In to a stable DC bias (e.g., VREF/2), enabling flexible interfacing with op-amp buffers, bridge sensors, or isolated amplifiers. Input leakage is ±1µA max, and absolute voltage limits are GND–0.3V to VCC+0.3V on +In and GND–0.3V to 4V on –In - constraints strictly enforced in all ADS7817EC applications.