Analog Devices Inc. AD7822BR

Overview

AD7822BR from Analog Devices is a single-channel, 8-bit, 2 MSPS analog-to-digital converter featuring a 420 ns conversion time, on-chip 2.5 V reference, and track-and-hold amplifier. It operates from a single 3 V ±10% or 5 V ±10% supply and supports standalone operation via EOC pulse for interrupt-driven data capture in real-time DSP front ends.

For engineers reviewing the AD7822BR datasheet, AD7822BR pinout, AD7822BR application, or AD7822BR equivalent, key selection considerations include its 1-channel architecture, automatic power-down on CONVST low, VMID-adjustable input span (0 V to 2 V @ 3 V, 0 V to 2.5 V @ 5 V), and compatibility with microprocessor parallel buses requiring minimal address decoding logic.

Technical Context

The AD7822BR implements a half-flash ADC architecture with two-stage conversion: a 4-bit coarse flash stage followed by a 4-bit fine flash stage, completing within 420 ns max. Its track-and-hold acquires input signals in ≤200 ns and supports full-power bandwidth up to 10 MHz for subsampling applications.

Channel selection is fixed (single-input), eliminating address bus requirements. Power management integrates convert start (CONVST) and automatic power-down into one pin: logic-low sampling at EOC high triggers shutdown, reducing idle current to 5 µA max without external control signals.

Key Specifications

Pinout & Package

AD7822BR is housed in a 20-lead, 0.3" wide plastic dual in-line package (PDIP) with standard through-hole mounting. Pin functions are validated per Analog Devices Rev. C datasheet Figure 3 and Table 4.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7825BR and MAX1186BCPP+, the AD7822BR uniquely combines single-channel simplicity, 3 V/5 V supply flexibility, VMID-based input offset tuning, and automatic power-down on CONVST - making it optimal for cost-sensitive, low-pin-count, high-throughput acquisition nodes.

Availability

AD7822BR is available at Aetrix Electronics and suitable for disk drive servo control, mobile communication subsampling, and DSP front-end acquisition requiring stable component supply and long-term industrial lifecycle support.

Supply support for AD7822BR 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 AD7822BR belongs to the AD782x family of high-speed, microprocessor-compatible ADCs designed specifically for real-time data acquisition in DSP, communications, and industrial control systems where low-latency, deterministic conversion and flexible power management are essential.

FAQ

What is the maximum sampling rate supported by the AD7822BR?

The AD7822BR supports a maximum throughput of 2 MSPS, corresponding to a guaranteed maximum conversion time of 420 ns. This rate is achievable across the full industrial temperature range (−40°C to +85°C) and under both 3 V ±10% and 5 V ±10% supply conditions, as verified in the Rev. C datasheet Table 1 and Table 2 timing specifications.

Does the AD7822BR require an external reference voltage?

No, the AD7822BR includes an on-chip 2.5 V reference with ±2% initial accuracy and 50 ppm/°C temperature coefficient, accessible at the VREF IN/OUT pin. External reference is optional and only needed when higher precision or different voltage levels are required; the AD7822BR operates fully functional with the internal reference enabled.

How does the automatic power-down feature work on the AD7822BR?

The AD7822BR samples the logic level on the CONVST pin at the moment the EOC signal goes high. If CONVST is low at that instant, the device enters power-down mode, reducing supply current to 5 µA max. This occurs automatically after each conversion unless CONVST is held high, enabling energy-efficient burst-mode operation without additional control circuitry.

Can the AD7822BR interface directly with a 3.3 V microcontroller?

Yes, the AD7822BR supports 3 V ±10% operation and specifies logic input thresholds of 2.0 V min (VIH) and 0.4 V max (VIL) at 3 V supply, fully compatible with 3.3 V CMOS/TTL interfaces. Its DB0–DB7 outputs drive 2.4 V min (VOH) at 200 µA sink, ensuring reliable high-level recognition by 3.3 V receivers without level shifters.

What is the purpose of the VMID pin on the AD7822BR?

The VMID pin sets the center point of the AD7822BR's analog input voltage span. When left unconnected, it defaults to 1.25 V (for 5 V supply) or 1.0 V (for 3 V supply), establishing a 0 V to 2.5 V or 0 V to 2 V input range. Connecting an external voltage to VMID shifts this center point anywhere between AGND and VDD, enabling offset compensation for single-supply sensor interfaces.