Analog Devices Inc. AD7817SR-REEL7

Overview

AD7817SR-REEL7 from Analog Devices is a 10-bit, 4-channel successive approximation ADC with integrated temperature sensor, 9 μs conversion time for analog inputs, ±2°C temperature measurement accuracy from −40°C to +85°C, and on-chip 2.5 V reference. It serves as a compact analog front-end in embedded environmental monitoring systems requiring simultaneous voltage and ambient temperature digitization.

For engineers reviewing the AD7817SR-REEL7 datasheet, AD7817SR-REEL7 pinout, AD7817SR-REEL7 application, or AD7817SR-REEL7 equivalent, key selection criteria include its single-supply 2.7 V–5.5 V operation, flexible SPI/MICROWIRE/8051-compatible serial interface, automatic power-down mode (4 μW at 10 SPS), and dedicated OTI output for overtemperature alerts without host intervention.

Technical Context

The AD7817SR-REEL7 implements a capacitor-based successive approximation register (SAR) architecture with inherent track-and-hold functionality, enabling accurate sampling of up to four single-ended analog inputs (VIN1–VIN4) or the on-chip temperature sensor (Channel 0). Its internal clock oscillator eliminates external timing components.

Conversion is initiated by a falling edge on CONVST; BUSY goes high during conversion and falls upon completion. The OTI pin asserts low when Channel 0's digitized result exceeds the programmable overtemperature register value, providing hardware-level thermal fault signaling independent of serial communication.

Key Specifications

Pinout & Package

AD7817SR-REEL7 is packaged in a narrow-body 16-lead SOIC (SO-16NB), 0.15 inch width, RoHS-compliant, tape-and-reel format (REEL7 denotes 1,000-unit reel).

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 AD7817SR-REEL7, AD7818ARZ-REEL7 reduces channel count and package size while retaining identical temperature performance and power profile; MAX1248BCAP+ trades integrated sensing for higher resolution and channel count but increases design effort and component count.

Availability

AD7817SR-REEL7 is available at Aetrix Electronics and suitable for industrial process monitoring, automotive climate control, and portable data logging requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AD7817SR-REEL7 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 belongs to Analog Devices' precision data acquisition portfolio, designed specifically for embedded systems needing compact, low-power, multi-sensor digitization with integrated thermal awareness.

FAQ

What is the maximum operating temperature range for the AD7817SR-REEL7?

The AD7817SR-REEL7 operates from −40°C to +85°C with full specification compliance. Its on-chip temperature sensor extends measurable range to −55°C to +125°C, though accuracy degrades outside the guaranteed industrial range. This makes AD7817SR-REEL7 suitable for under-hood automotive or outdoor industrial enclosures where extended thermal margins are needed.

Does the AD7817SR-REEL7 require an external crystal or clock source?

No, the AD7817SR-REEL7 contains an on-chip clock oscillator and requires no external timing components. All timing-including conversion initiation, sampling, and serial interface synchronization-is derived internally. This simplifies design, reduces bill-of-materials cost, and improves reliability compared to externally clocked ADCs.

How is the temperature sensor accessed in the AD7817SR-REEL7?

The temperature sensor is mapped to Channel 0 of the AD7817SR-REEL7. To read temperature, firmware writes address 000 to the internal address register via the serial interface, then initiates conversion with CONVST. The resulting 10-bit code corresponds directly to temperature with 0.25°C/LSB resolution. AD7817SR-REEL7 outputs this value on DOUT after conversion completes.

Can the AD7817SR-REEL7 operate from a 3.3 V supply?

Yes, the AD7817SR-REEL7 supports a wide supply range of 2.7 V to 5.5 V. At 3.3 V, it maintains full 10-bit performance, including ±2°C temperature accuracy and 9 μs conversion time. Power consumption scales linearly: typical IDD is 1.6 mA in normal operation and drops to 2 μA in power-down mode at 3 V, making AD7817SR-REEL7 ideal for 3.3 V embedded systems.

What serial interface protocols does the AD7817SR-REEL7 support?

The AD7817SR-REEL7 supports Intel 8051, Motorola SPI, and National Semiconductor MICROWIRE protocols via its 4-wire serial interface (DIN, DOUT, SCLK, RD/WR). No configuration registers are needed-the interface adapts automatically based on timing and signal polarity. This ensures drop-in compatibility with legacy and modern microcontrollers without custom driver development for AD7817SR-REEL7.