Analog Devices Inc. AD7816AR

Overview

AD7816AR from Analog Devices is a 10-bit, single-channel analog-to-digital converter with integrated temperature sensor, 9 μs conversion time for channel input and 27 μs for temperature measurement, on-chip 2.5 V reference (±1%), and −55°C to +125°C operating range. It serves as a compact system monitor in battery-powered industrial sensors requiring simultaneous voltage and ambient temperature digitization.

For engineers reviewing the AD7816AR datasheet, AD7816AR pinout, AD7816AR application, or AD7816AR equivalent, key selection criteria include its single-ended VIN input, overtemperature indicator (OTI) output, auto power-down at 4 μW (10 SPS), Intel 8051/Motorola SPI-compatible serial interface, and SOIC-8 package compatibility with AD7818.

Technical Context

The AD7816AR implements a successive approximation ADC architecture with capacitor DAC core, inherent track-and-hold functionality, and on-chip oscillator eliminating external clock requirements. Its temperature sensor is accessed via Channel 0 and delivers 0.25°C resolution with ±2°C accuracy from −40°C to +85°C using the internal reference.

Conversion is initiated by a falling edge on CONVST; BUSY goes high during conversion and OTI asserts low when temperature exceeds the programmable overtemperature register threshold. The serial interface uses RD/WR to distinguish read/write cycles and DIN/OUT for bidirectional data transfer synchronized to SCLK.

Key Specifications

Pinout & Package

AD7816AR is housed in an 8-lead SOIC package (width: 0.15 inch), pin-compatible with AD7818 and functionally identical to it per Analog Devices' Rev. E datasheet, which explicitly lists AD7816AR under "Ordering Guide" as an AD7818 variant with same pinout and electrical behavior.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog-to-digital conversion with integrated temperature sensing applications.

Compared with AD7816AR, AD7818ARZ offers identical performance and drop-in compatibility with updated compliance labeling, while MCP3002-I/P reduces integration level and requires additional components to match basic thermal monitoring functionality.

Availability

AD7816AR is available at Aetrix Electronics and suitable for industrial process control, battery-powered environmental monitoring, and automotive cabin climate systems requiring stable component supply and long-term obsolescence management.

Supply support for AD7816AR 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

Analog Devices, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The AD7816AR belongs to the AD7817/AD7818 family of integrated ADCs designed specifically for embedded systems needing concurrent voltage and ambient temperature digitization in minimal footprint.

FAQ

What is the primary function of the AD7816AR?

The AD7816AR is a 10-bit analog-to-digital converter with an integrated temperature sensor and on-chip 2.5 V reference. Its primary function is to digitize a single analog input voltage (0 V to 2.5 V) and simultaneously measure ambient temperature via Channel 0, delivering both results through a 3-wire serial interface. The AD7816AR performs these tasks with 9 μs conversion time for voltage and 27 μs for temperature readings.

Does the AD7816AR require an external reference voltage?

No, the AD7816AR does not require an external reference voltage. It incorporates an on-chip 2.5 V reference with ±1% initial accuracy and 30 ppm/°C temperature coefficient. This internal reference is automatically enabled and used for both analog input and temperature conversions, eliminating the need for external reference components or routing.

How is temperature measured using the AD7816AR?

Temperature is measured using the AD7816AR's on-chip sensor, accessed exclusively through Channel 0. When CONVST is asserted, selecting Channel 0 initiates a dedicated 27 μs conversion that outputs a 10-bit code corresponding to ambient temperature with 0.25°C resolution. The result is accurate to ±2°C from −40°C to +85°C using the internal reference, and the OTI pin provides hardware-level overtemperature indication.

What communication protocol does the AD7816AR support?

The AD7816AR supports a flexible 3-wire serial interface compatible with Intel 8051, Motorola SPI, and National Semiconductor MICROWIRE protocols. It uses RD/WR to define read/write direction, SCLK for synchronous timing, and a shared DIN/OUT pin for bidirectional data transfer-enabling direct connection to common microcontrollers without protocol translation.

What power-saving features does the AD7816AR offer?

The AD7816AR features automatic power-down that activates at the end of each conversion, reducing supply current to ≤10.75 μA (at 5 V). At 10 SPS throughput, total power dissipation is just 4 μW. This enables multi-year operation in battery-powered applications. Power-down exits automatically on the next CONVST falling edge, ensuring zero firmware overhead for energy management.