Texas Instruments ADS7817P

Overview

ADS7817P from Texas Instruments is a 12-bit, 200kHz SAR analog-to-digital converter with fully differential high-impedance inputs, 2.3mW power consumption at full rate, ±2 LSB integral linearity, and support for external reference voltages from 100mV to 2.5V. It serves as a precision front-end digitizer in low-power transducer interface circuits.

For engineers reviewing the ADS7817P datasheet, ADS7817P pinout, ADS7817P application, or ADS7817P equivalent, key selection considerations include its micro-power operation at 200kHz, true differential input architecture, serial CMOS interface timing, and MSOP-8/SO-8/DIP-8 package compatibility across performance grades (P/U/E).

Technical Context

The ADS7817P implements a capacitive redistribution successive approximation register (SAR) architecture on 0.6µm CMOS, integrating sample-and-hold functionality. It requires an external clock (10kHz–3.2MHz), external reference (100mV–2.5V), and single +5V supply.

Its analog input accepts bipolar differential signals with ±VREF span and supports single-ended operation via fixed common-mode bias. Conversion data is output serially, MSB-first, on DOUT synchronized to DCLOCK falling edges, with no pipeline delay.

Key Specifications

Pinout & Package

ADS7817P is packaged in plastic DIP-8 (drawing 006) with 0.3-inch width and through-hole mounting. Pin functions are validated per TI SBAS066A datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816U, the ADS7817P delivers double the sampling rate with only marginally higher power; compared with ADS8320EB, it trades 4-bit resolution for 80% lower power and binary-compatible firmware integration-making it the balanced choice for embedded control and portable sensing.

Availability

ADS7817P is available at Aetrix Electronics and suitable for transducer interface, battery-operated systems, and remote data acquisition requiring stable component supply across industrial temperature ranges (–40°C to +85°C).

Supply support for ADS7817P 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 company founded in 1930, specializing in analog and embedded processing technologies with leadership in data converters, power management, and signal chain solutions.

The ADS7817P belongs to TI's precision SAR ADC product line, designed specifically for low-power, high-resolution digitization in space- and energy-constrained applications such as portable instrumentation and distributed sensing.

FAQ

What is the maximum sampling rate supported by the ADS7817P?

The ADS7817P supports a maximum sampling rate of 200kHz, achieved with a 3.2MHz DCLOCK signal (16× oversampling). At this rate, the device consumes 2.3mW and maintains ±2 LSB integral linearity. Lower rates reduce power linearly-e.g., 10kHz sampling draws ~40µA quiescent current-making the ADS7817P adaptable to both high-speed control loops and ultra-low-power wake-on-event systems.

Does the ADS7817P require an external reference voltage?

Yes, the ADS7817P requires an external reference voltage applied to the VREF pin, which must be between 100mV and 2.5V. This reference directly sets the full-scale input range (±VREF) and determines LSB size-for example, 1.22mV at 2.5V or 49µV at 100mV. The ADS7817P does not include an internal reference; using a stable, low-noise external source (e.g., REF5025) is essential for achieving specified linearity and noise performance.

What package options are available for the ADS7817P?

The ADS7817P is offered exclusively in the plastic DIP-8 package (drawing 006), with 0.3-inch width and through-hole mounting. Other variants in the ADS7817 family include ADS7817U (SO-8) and ADS7817E (MSOP-8), but the 'P' suffix denotes the DIP-8 version. All share identical pinout and electrical specifications, allowing drop-in replacement across packages where board layout permits.

How does the ADS7817P handle power-down mode?

The ADS7817P enters low-power shutdown when the CS/SHDN pin is driven HIGH, drawing ≤3µA. In this state, both analog and digital sections are powered down. When CS is LOW, the device operates normally-but after conversion completes, the analog section automatically powers down until the next CS falling edge. This dual-stage power management enables aggressive duty cycling: for instance, 1ms active conversion followed by 99ms shutdown yields average current under 50µA.

Can the ADS7817P interface directly with a microcontroller's SPI port?

The ADS7817P uses a synchronous 3-wire serial interface (CS/DCLOCK/DOUT) compatible with standard SPI hardware, though it is not a full SPI slave. It outputs MSB-first two's complement data on DOUT synchronized to DCLOCK falling edges, with no MISO/MOSI bidirectional requirement. Most microcontrollers can drive it using GPIO-controlled bit-banging or SPI master mode with CPHA=0 and CPOL=0, provided setup/hold timing (e.g., 85ns DOUT valid after DCLOCK fall) is met per SBAS066A Table I.