Analog Devices Inc. AD7817BR-REEL

Overview

AD7817BR-REEL from Analog Devices is a 10-bit, 4-channel successive approximation ADC with integrated temperature sensor, 9 μs conversion time for analog channels, on-chip 2.5 V ±1% reference, and overtemperature indicator output. It operates from 2.7 V to 5.5 V and delivers ±1 LSB relative accuracy across −40°C to +85°C - used in industrial process control systems requiring simultaneous voltage monitoring and ambient thermal sensing.

For engineers reviewing the AD7817BR-REEL datasheet, AD7817BR-REEL pinout, AD7817BR-REEL application, or AD7817BR-REEL equivalent, key selection criteria include its 4-channel single-ended analog input architecture, channel-to-channel isolation of −80 dB at 20 kHz, automatic power-down mode (4 μW at 10 SPS), and OTI logic-low overtemperature alert triggered by Channel 0 readings exceeding user-programmed threshold.

Technical Context

The AD7817BR-REEL implements a capacitor-based SAR architecture with inherent track-and-hold functionality and an internal clock oscillator - eliminating need for external timing components. Its conversion sequence begins on CONVST falling edge, places T/H into hold mode, and completes in 9 μs for VIN1–VIN4 or 27 μs for temperature sensor (Channel 0).

It supports flexible serial interface compatibility with Intel 8051, Motorola SPI/QSPI, and National Semiconductor MICROWIRE protocols via CS, RD/WR, SCLK, DIN, and DOUT pins. The on-chip temperature sensor provides 0.25°C resolution and ±2°C error from −40°C to +85°C when using external 2.5 V reference, with OTI output asserting low upon register-matched overtemperature event.

Key Specifications

Pinout & Package

AD7817BR-REEL is housed in a narrow-body 16-lead SOIC package (0.15 inch width) with standard JEDEC MS-012AC footprint and 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit multichannel ADC with temperature sensing applications.

Compared with AD7818ARZ, AD7817BR-REEL provides four analog inputs instead of one - essential for multi-sensor systems - while retaining identical temperature accuracy, power profile, and serial compatibility. Against MAX1248BCPP+, AD7817BR-REEL trades 2 bits of resolution for integrated thermal sensing, reduced layout complexity, and lower total system cost in thermal-aware monitoring applications.

Availability

AD7817BR-REEL is available at Aetrix Electronics and suitable for industrial process control, automotive battery management, and environmental data acquisition requiring stable component supply and long-term lifecycle support.

Supply support for AD7817BR-REEL 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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD7817 product line delivers integrated 10-bit SAR ADCs with on-chip temperature sensing for space-constrained, low-power industrial and automotive monitoring systems - designed to reduce system-level component count and improve thermal measurement fidelity.

FAQ

What is the maximum operating temperature range for the AD7817BR-REEL?

The AD7817BR-REEL operates from −40°C to +85°C with guaranteed specifications, and its on-chip temperature sensor functions across −55°C to +125°C. This extended sensor range allows reliable thermal monitoring beyond the IC's own operational limits - critical for safety-critical applications like battery thermal runaway detection. The AD7817BR-REEL maintains ±2°C accuracy from −40°C to +85°C when using the external 2.5 V reference.

How does the AD7817BR-REEL handle reference voltage selection?

The AD7817BR-REEL supports either internal or external reference: tie REFIN to AGND to enable the on-chip 2.5 V ±1% reference, or apply a precise 2.5 V source to REFIN to disable the internal reference. When external reference is used, the internal reference shuts down automatically. The AD7817BR-REEL's temperature sensor accuracy depends on reference tolerance - ±2°C error assumes 2.5 V ±1% input. This dual-reference flexibility lets designers optimize for cost (internal) or precision (external) without changing the AD7817BR-REEL footprint.

Can the AD7817BR-REEL perform simultaneous conversions on all four analog channels?

No, the AD7817BR-REEL performs sequential conversions - one channel at a time - selected via its 3-bit address register. Each conversion takes 9 μs for VIN1–VIN4 or 27 μs for the temperature sensor (Channel 0). However, its 4-channel architecture and fast conversion time enable rapid interleaved sampling (e.g., ~36 μs for full 4-channel cycle), and the BUSY pin provides precise timing for synchronization. The AD7817BR-REEL does not support true simultaneous sampling, but its channel-to-channel isolation of −80 dB at 20 kHz minimizes crosstalk during sequential acquisition.

What is the function of the OTI pin on the AD7817BR-REEL?

The OTI (Overtemperature Indicator) pin on the AD7817BR-REEL is an active-low, open-drain output that asserts logic low when the temperature reading from Channel 0 exceeds the value stored in the on-chip 8-bit overtemperature register (OTR). It resets automatically at the end of a serial read operation (rising edge of RD/WR with CS low). This hardware-level alert allows immediate system response - such as disabling power stages or triggering fan control - without MCU intervention, enhancing safety in thermal-critical applications. The AD7817BR-REEL's OTI is fully programmable and independent of software polling.

Does the AD7817BR-REEL require an external clock source?

No, the AD7817BR-REEL contains an on-chip clock oscillator and requires no external clock source for basic operation. Its internal clock drives the 10-bit successive approximation conversion process, enabling standalone functionality with only power, ground, and serial interface connections. External clocking is not supported; all timing is derived internally. The SCLK pin is used solely for synchronizing serial data transfers - not for ADC conversion timing - making the AD7817BR-REEL simpler to deploy than externally clocked ADCs. This self-contained timing reduces system-level component count and layout sensitivity.