Analog Devices Inc. AD7823YRM-REEL7

Overview

AD7823YRM-REEL7 from Analog Devices is an 8-bit successive approximation ADC with 4 µs typical conversion time, pseudo-differential analog input (VIN+, VIN–), and microcontroller-compatible 3-wire serial interface (CONVST, SCLK, DOUT). It operates from a single 2.7 V to 5.5 V supply, features inherent track-and-hold functionality, and is specified over –40°C to +125°C for battery-powered portable instrumentation.

For engineers reviewing the AD7823YRM-REEL7 datasheet, AD7823YRM-REEL7 pinout, AD7823YRM-REEL7 application, or AD7823YRM-REEL7 equivalent, key selection considerations include its automatic power-down mode (1 µA max standby current), 8-lead microSOIC package (RM-8), ±0.5 LSB relative accuracy, and support for unipolar 0 V to VREF input range with internal charge redistribution DAC architecture.

Technical Context

The AD7823YRM-REEL7 implements a charge redistribution DAC-based SAR architecture with built-in track-and-hold, eliminating external sample-and-hold circuitry. Its pseudo-differential input allows offset cancellation by applying system offset to VIN– while routing signal to VIN+, provided VIN– variation stays within ±0.5 LSB during conversion.

It supports two operating modes: Mode 1 (high-speed, no inter-conversion power-down, 4 µs typ conversion) and Mode 2 (automatic power-down after each conversion, 1.5 µs power-up + 5 µs max conversion, enabling 54 µW at 1 kSPS). Serial data output is edge-triggered on rising SCLK, with CONVST serving dual roles - conversion start (falling edge) and serial port enable (rising edge).

Key Specifications

Pinout & Package

AD7823YRM-REEL7 is housed in an 8-lead microSOIC package (RM-8), 3.0 mm × 3.0 mm body, 0.65 mm lead pitch, JEDEC MO-187AC compliant. Pin 1 marked via laser scribe or dimple.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit SAR ADC applications.

Compared with AD7823YRM-REEL7, AD7810YRM-REEL7 offers higher resolution in identical packaging but increases power and firmware complexity, while ADS7822U sacrifices temperature range, power management, and input flexibility to reduce interface pin count and BOM cost.

Availability

AD7823YRM-REEL7 is available at Aetrix Electronics and suitable for battery-powered test equipment, portable communications systems, and automotive cabin monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7823YRM-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 semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The AD7823 belongs to Analog Devices' legacy high-speed, low-power SAR ADC product line, designed specifically for space-constrained, battery-operated instrumentation where conversion speed, power efficiency, and temperature robustness are critical.

FAQ

What is the absolute maximum input voltage on VIN+ and VIN– for AD7823YRM-REEL7?

The absolute maximum analog input voltage on VIN+ and VIN– is –0.3 V to VDD + 0.3 V. Exceeding this range risks forward-biasing internal ESD diodes, potentially causing latch-up or irreversible damage. For reliable operation, keep inputs within 0 V to VREF, and ensure VREF does not exceed VDD. The AD7823YRM-REEL7 datasheet specifies 125 Ω internal multiplexer resistance and 3.5 pF sampling capacitance, which further constrain safe drive conditions.

Does AD7823YRM-REEL7 require an external reference voltage?

No, AD7823YRM-REEL7 does not require an external reference. Its VREF pin accepts 1.2 V to VDD, so connecting VREF directly to VDD establishes a 0 V to VDD unipolar input range and eliminates the need for a precision external reference. This configuration is explicitly supported in the datasheet's Typical Connection Diagram (Figure 6) and reduces BOM count and board area - a key advantage in compact portable designs using the AD7823YRM-REEL7.

How does the automatic power-down mode work in AD7823YRM-REEL7?

In AD7823YRM-REEL7 Mode 2, the device powers down automatically at the end of each conversion when CONVST remains low. A rising edge on CONVST first powers up the part (1.5 µs), then a falling edge starts conversion (5 µs max). After conversion completes, the part enters standby (1 µA max IDD). This cuts average power to 54 µW at 1 kSPS - critical for battery longevity. The AD7823YRM-REEL7 serial interface remains functional during power-down, allowing data readout without re-powering.

Can AD7823YRM-REEL7 interface directly with an 8051 microcontroller?

Yes, AD7823YRM-REEL7 can interface with an 8051, but the SCLK signal must be inverted because the AD7823YRM-REEL7 expects data to be sampled on rising SCLK edges, while the 8051's standard SPI peripheral clocks on falling edges. This inversion can be implemented with a simple transistor inverter or programmable logic. The CONVST and DOUT signals connect directly. The AD7823YRM-REEL7 datasheet explicitly references 8051 compatibility in the "Microprocessor Interfacing" section.

What is the guaranteed minimum sampling rate for AD7823YRM-REEL7 in high-speed mode?

The AD7823YRM-REEL7 has a typical conversion time of 4 µs in Mode 1 (high-speed), supporting a theoretical maximum sampling rate of 250 kSPS. However, the actual sustained throughput depends on the microcontroller's serial interface speed - the datasheet states "maximum throughput rate is dependent on the speed of the serial interface of the microcontroller." For reliable operation, allow ≥5 µs between CONVST falling edges to complete conversion and serial read, yielding ~200 kSPS in practice. This limit is intrinsic to the AD7823YRM-REEL7's architecture, not a datasheet omission.