Texas Instruments ADS7817UC

Overview

ADS7817UC from Texas Instruments is a 12-bit, 200kHz SAR analog-to-digital converter with fully differential high-impedance inputs, 2.5V reference support (±0.75 LSB integral linearity), serial CMOS interface, and micro-power operation (2.3mW at full rate). It serves as a precision transducer interface in battery-powered remote data acquisition systems.

For engineers reviewing the ADS7817UC datasheet, ADS7817UC pinout, ADS7817UC application, or ADS7817UC equivalent, this page delivers verified technical context, SO-8 package mapping, real-world timing behavior, and validated alternative options for low-power differential ADC selection.

Technical Context

The ADS7817UC implements a capacitive redistribution successive approximation register (SAR) architecture on 0.6µm CMOS, integrating sample-and-hold functionality. Its analog input accepts true differential bipolar signals up to ±2.5V with AC common-mode rejection and supports external reference voltages from 100mV to 2.5V.

Digital communication uses a 3-wire synchronous serial interface (CS/SHDN, DCLOCK, DOUT) with MSB-first binary two's complement output. Conversion is initiated by CS falling edge; data becomes valid after one null bit and 12 subsequent clock edges, with no pipeline delay.

Key Specifications

Pinout & Package

ADS7817UC is packaged in an SO-8 (SOIC-8) surface-mount package with standard 1.27 mm pitch, 5.0 mm × 4.0 mm body size, and JEDEC MS-012AC outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7817UC, ADS7816U trades half the sampling bandwidth for lower cost and relaxed linearity, while ADS7822U matches speed and power but sacrifices differential input capability-requiring additional signal conditioning hardware in transducer applications.

Availability

ADS7817UC is available at Aetrix Electronics and suitable for remote data acquisition, battery-operated instrumentation, and isolated industrial sensing requiring stable component supply across long production lifecycles.

Supply support for ADS7817UC 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 focused on analog and embedded processing technologies, with decades of expertise in precision data converters and low-power design.

The ADS7817UC belongs to TI's precision SAR ADC product line, engineered specifically for ultra-low-power, high-accuracy measurement in portable and distributed sensing systems.

FAQ

What is the maximum sampling rate supported by the ADS7817UC?

The ADS7817UC supports a maximum sampling rate of 200 kHz, achieved with a 3.2 MHz DCLOCK frequency (16× oversampling ratio). At this rate, the device consumes 2.3 mW and maintains ±1 LSB integral linearity over the full –40°C to +85°C operating range. Lower rates reduce power linearly-e.g., 12.5 kHz sampling draws only 40 µA quiescent current.

Does the ADS7817UC require an external reference voltage?

Yes, the ADS7817UC requires an external reference voltage applied to the VREF pin. It operates with references from 100 mV to 2.5 V, directly defining the full-scale input span (±VREF). The reference must be stable and low-noise-TI recommends bypassing with a 0.1 µF ceramic capacitor placed near the VREF pin to maintain ENOB performance.

What package type is used for the ADS7817UC?

The ADS7817UC is supplied in an SO-8 (SOIC-8) package, per TI's ordering table designation "ADS7817UC" and drawing number 182. This 5.0 mm × 4.0 mm surface-mount package features gull-wing leads, 1.27 mm pitch, and JEDEC MS-012AC compliance-compatible with standard reflow profiles and automated assembly.

How does the ADS7817UC enter power-down mode?

The ADS7817UC enters full power-down mode when the CS/SHDN pin is driven HIGH, reducing supply current to ≤3 µA. It also automatically powers down analog circuitry after each conversion completes-even if CS remains LOW-but digital logic stays active unless CS is asserted HIGH. For minimum power, assert CS HIGH between conversions.

Can the ADS7817UC interface directly with a microcontroller's SPI port?

The ADS7817UC uses a 3-wire synchronous serial interface compatible with SPI hardware in master mode, but it is not a standard SPI peripheral: it outputs data MSB-first on DOUT synchronized to DCLOCK falling edges, requires no MOSI input, and has no dedicated chip-select polarity configuration. Most MCUs can drive it using GPIO-controlled clock and CS with bit-banged read routines.