Analog Devices Inc. AD7823YR

Overview

AD7823YR from Analog Devices is an 8-bit successive approximation ADC with inherent track-and-hold, 4 µs typical conversion time, ±1 LSB total unadjusted error, and operation from 2.7 V to 5.5 V - used in battery-powered test equipment for precise analog-to-digital conversion of pseudo-differential sensor signals.

For engineers reviewing the AD7823YR datasheet, AD7823YR pinout, AD7823YR application, or AD7823YR equivalent, key selection considerations include its automatic power-down mode (54 µW at 1 kSPS), microSOIC-8 package footprint, serial interface timing compatibility with PIC/QSPI/SPI controllers, and guaranteed 8-bit no-missing-codes performance over –40°C to +125°C.

Technical Context

The AD7823YR implements a charge redistribution DAC architecture with internal oscillator and pseudo-differential input (VIN+, VIN–), enabling offset cancellation in unipolar current-sense applications. Its control logic samples CONVST state at conversion end to trigger automatic power-down.

It supports two operating modes: Mode 1 (high-speed, no inter-conversion power-down, 4 µs conversion) and Mode 2 (automatic power-down, 6.5 µs effective cycle time including 1.5 µs wake-up). Serial data output (DOUT) is enabled on CONVST rising edge and synchronized to SCLK rising edges.

Key Specifications

Pinout & Package

AD7823YR is housed in an 8-lead microSOIC package (SO-8 footprint, 1.9 mm × 2.8 mm, 0.65 mm pitch), compatible with standard SOIC reflow profiles and offering 40% area reduction versus mini-DIP.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7823YR, AD7810YR delivers 2 extra bits of resolution with zero layout impact, while ADS7822U trades pin compatibility for tighter SPI protocol alignment - making AD7823YR optimal for space-constrained, ultra-low-power, single-supply designs needing minimal external components.

Availability

AD7823YR is available at Aetrix Electronics and suitable for battery-powered test equipment, industrial sensor signal conditioning, and automotive ECU diagnostics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7823YR 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 company specializing in high-performance analog, mixed-signal, and digital signal processing ICs for precision measurement and control.

The AD7823YR belongs to Analog Devices' legacy SAR ADC product line designed for low-power, space-constrained embedded systems requiring guaranteed monotonicity and wide-temperature operation without calibration.

FAQ

What is the maximum sampling rate achievable with the AD7823YR?

The AD7823YR achieves a maximum throughput rate of approximately 133 kSPS under optimal conditions: VDD = 5 V, fIN = 30 kHz, and a microcontroller serial interface capable of sustaining >20 MHz SCLK. This limit arises from the 4 µs conversion time plus serial read overhead - actual system rate depends on host processor SCLK generation speed and software latency.

Does the AD7823YR require an external reference voltage?

No, the AD7823YR does not require an external reference voltage. Its VREF pin accepts 1.2 V to VDD, and connecting VREF directly to VDD establishes a 0 V to VDD analog input range - enabling ratiometric operation and eliminating external reference components in many battery-powered applications.

How does the automatic power-down mode reduce power consumption in the AD7823YR?

The AD7823YR automatic power-down mode reduces power by powering down the analog core and internal oscillator immediately after conversion completion when CONVST remains low. At 1 kSPS, this yields just 54 µW average dissipation - a >99% reduction versus continuous operation - because the device draws only 1 µA in standby between conversions.

Can the AD7823YR interface directly with an 8051 microcontroller?

Yes, the AD7823YR can interface directly with an 8051 microcontroller, but the SCLK signal must be inverted externally (e.g., using a 74HC04) because the AD7823YR expects data valid on SCLK rising edges, whereas standard 8051 SPI peripherals drive data on falling edges. The CONVST and DOUT lines connect directly without level-shifting at 3.3 V or 5 V operation.

What is the purpose of the pseudo-differential input structure in the AD7823YR?

The pseudo-differential input structure in the AD7823YR allows VIN– to serve as a programmable offset reference, enabling rejection of common-mode voltage shifts (e.g., sensor bias or harness noise) while maintaining unipolar input range on VIN+. For example, applying 0.5 V to VIN– and the signal to VIN+ effectively measures (VIN+ − 0.5 V) with respect to ground - useful in thermocouple or current-sense applications.