Analog Devices Inc. AD7823YRM

Overview

AD7823YRM from Analog Devices is an 8-bit successive approximation ADC with inherent track-and-hold, 4 µs typical conversion time, ±1 LSB gain error, and operation from 2.7 V to 5.5 V supply - used in battery-powered test equipment for high-speed, low-power analog-to-digital conversion of pseudo-differential signals.

For engineers reviewing the AD7823YRM datasheet, AD7823YRM pinout, AD7823YRM application, or AD7823YRM equivalent, key selection considerations include its microSOIC-8 package, automatic power-down mode enabling 54 µW at 1 kSPS, pseudo-differential input architecture, serial interface timing compatibility with PIC/QSPI/SPI controllers, and guaranteed no missing codes over –40°C to +125°C.

Technical Context

The AD7823YRM implements a charge redistribution DAC-based SAR architecture with internal oscillator and pseudo-differential input stage (VIN+, VIN–), where VIN– serves as offset reference and must remain stable within ±½ LSB during conversion. Its control logic samples CONVST state at conversion end to enable 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 after each conversion, effective 6.5 µs cycle at 3 V). Serial data output on DOUT is edge-aligned to SCLK rising edges, with CONVST rising edge resetting the bit counter and enabling the port.

Key Specifications

Pinout & Package

AD7823YRM is housed in an 8-lead microSOIC package (RM-8), 3 mm × 3 mm body, 0.65 mm lead pitch, gull-wing leads. This compact footprint supports high-density PCB layouts in portable instrumentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7823YRM, AD7810YRM trades power efficiency for resolution and SNR, while ADS7822U sacrifices temperature range and power management for raw speed - making AD7823YRM the optimal balance for rugged, battery-constrained industrial sensing.

Availability

AD7823YRM is available at Aetrix Electronics and suitable for battery-powered test equipment, portable communications systems, and industrial sensor interface modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7823YRM 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, with design centers worldwide and ISO 9001-certified manufacturing.

The AD7823YRM belongs to Analog Devices' precision data acquisition portfolio, designed specifically for space-constrained, low-power, wide-temperature industrial and portable instrumentation applications requiring robust serial interfacing and inherent track-and-hold functionality.

FAQ

What is the package type and footprint of the AD7823YRM?

The AD7823YRM uses an 8-lead microSOIC package (RM-8) with 3 mm × 3 mm body size and 0.65 mm lead pitch. It is pin-compatible with other AD7823 variants in SOIC-8 and mini-DIP packages but requires rework of land pattern due to smaller pad spacing and gull-wing lead form. The RM-8 footprint supports high-density layouts in handheld instruments and sensor nodes.

Does the AD7823YRM require an external reference voltage?

No, the AD7823YRM does not require an external reference. Its VREF pin accepts 1.2 V to VDD, and tying VREF directly to VDD establishes a 0 V to VDD analog input range - eliminating external reference components and reducing BOM count. This configuration maintains full 8-bit linearity and ±1 LSB gain error across the –40°C to +125°C range.

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

In automatic power-down mode (Mode 2), the AD7823YRM powers down immediately after conversion completion when CONVST remains low. A rising edge on CONVST wakes it up (~1.5 µs power-up time), then a falling edge starts conversion. At 1 kSPS and 3 V, this yields 54 µW average power. The feature is controlled solely by CONVST timing - no register writes or configuration pins are needed.

Can the AD7823YRM interface directly with an SPI microcontroller?

Yes, the AD7823YRM interfaces directly with SPI-compatible microcontrollers using its 3-wire serial interface (CONVST as chip select, SCLK as clock, DOUT as data out). No level shifters or glue logic are required. For standard SPI masters, CONVST replaces CS#; SCLK polarity and phase match Mode 0 (CPOL = 0, CPHA = 0). The 8051 requires SCLK inversion due to timing alignment.

What is the maximum recommended source impedance for the analog input of the AD7823YRM?

The AD7823YRM's analog input sampling capacitor is 3.5 pF, and internal series resistance is 125 Ω. To achieve full-spec 100 ns acquisition time and ±1 LSB accuracy, the total source impedance (including sensor, filter, and trace resistance) must be ≤125 Ω. Higher impedances increase settling time exponentially - e.g., 4.6 kΩ raises acquisition time to >1 µs and degrades THD at high throughput rates.