Texas Instruments ADS7817EC/250

Overview

ADS7817EC/250 from Texas Instruments is a 12-bit, 200kHz SAR analog-to-digital converter with fully differential high-impedance inputs, 2.3mW active power at full rate, 3µA shutdown current, and configurable 0.1V–2.5V reference voltage-enabling sub-1.22mV input-referred resolution. It serves as a precision front-end digitizer for low-power transducer interfaces in battery-operated remote sensing systems.

For engineers reviewing the ADS7817EC/250 datasheet, ADS7817EC/250 pinout, ADS7817EC/250 application, or ADS7817EC/250 equivalent, key selection considerations include its MSOP-8 package, bipolar differential input architecture, serial CMOS interface timing, and trade-offs between reference voltage scaling and noise/linearity performance.

Technical Context

The ADS7817EC/250 implements a capacitive redistribution successive approximation register (SAR) architecture on 0.6µm CMOS, integrating sample-and-hold functionality. Its analog core operates with external clock (10kHz–3.2MHz), external reference (0.1V–2.5V), and single +5V supply-no internal reference or oscillator is included.

Conversion is initiated by CS/SHDN falling edge; sampling occurs over 1.5–2.0 clock cycles, followed by 12-cycle conversion and serial MSB-first output on DOUT synchronized to DCLOCK falling edges. Power-down is asserted when CS/SHDN is HIGH, reducing supply current to ≤3µA while disabling both analog and digital sections.

Key Specifications

Pinout & Package

ADS7817EC/250 is housed in an 8-pin MSOP package (3.0mm × 3.0mm × 1.0mm body height, 0.65mm pitch), optimized for space-constrained PCB layouts in portable instrumentation and isolated data acquisition modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7817EC/250, ADS7816E/250 trades half the throughput for ~48% lower active power, while ADS8325IBDR delivers 4 extra bits of resolution at the cost of fixed reference architecture and larger package-making ADS7817EC/250 optimal for space-constrained, variable-reference, 200kHz-capable systems.

Availability

ADS7817EC/250 is available at Aetrix Electronics and suitable for battery-operated instrumentation, remote sensor networks, and isolated industrial monitoring requiring stable component supply and long-term production continuity.

Supply support for ADS7817EC/250 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 high-reliability ICs for industrial, automotive, and communications markets.

The ADS7817EC/250 belongs to TI's precision data acquisition portfolio, designed specifically for low-power, high-accuracy digitization in resource-constrained embedded systems where size, energy efficiency, and differential noise immunity are critical.

FAQ

What is the minimum reference voltage supported by the ADS7817EC/250?

The ADS7817EC/250 supports an external reference voltage as low as 0.1V. At this level, the LSB size is 49µV, enabling high-resolution measurement of small-signal transducers-but with increased sensitivity to noise and reduced effective number of bits (ENOB). The device maintains specified linearity and monotonicity across the full 0.1V–2.5V range.

Does the ADS7817EC/250 include an internal reference or clock generator?

No, the ADS7817EC/250 requires both an external reference voltage (0.1V–2.5V) and an external clock (10kHz–3.2MHz). It contains no internal reference or oscillator. This design allows system-level optimization of reference stability and clock jitter-critical for maintaining SINAD >71dB and SFDR >86dB at 1kHz input.

How does the ADS7817EC/250 achieve 3µA shutdown current?

The ADS7817EC/250 achieves ≤3µA shutdown current by asserting full power-down when CS/SHDN is driven HIGH. This disables both analog circuitry (comparator, S/H amp, CDAC) and digital logic (serial interface, control state machine). The specification is guaranteed over –40°C to +85°C and applies regardless of clock or reference conditions.

Can the ADS7817EC/250 interface directly with a microcontroller GPIO without level-shifting?

Yes-the ADS7817EC/250 uses CMOS-compatible digital I/O with VIH ≥3.0V and VIL ≤0.8V at +5V supply, matching standard 5V microcontrollers. No level-shifting is required when interfacing with 5V logic families; however, for 3.3V MCUs, verify that their VOH meets ADS7817EC/250's VIH minimum under load, as the ADS7817EC/250 does not support mixed-voltage I/O.

What layout practices are essential to achieve specified 12-bit performance with the ADS7817EC/250?

To achieve full 12-bit performance, place a 0.1µF ceramic bypass capacitor within 2mm of ADS7817EC/250's +VCC and GND pins; route GND to a dedicated analog ground plane; isolate reference traces from digital routing; and avoid routing high-speed clocks or switching node traces near +In/–In or VREF. These practices suppress noise-induced DNL/INL degradation and preserve 80dB CMRR.