Analog Devices Inc. AD7822BRZ

Overview

AD7822BRZ from Analog Devices is a high-speed, single-channel, 8-bit parallel-output analog-to-digital converter (ADC) with 420 ns conversion time, on-chip 2.5 V reference, track-and-hold amplifier, and automatic power-down functionality. It operates from 3 V ±10% or 5 V ±10% supply and supports 0 V to 2 V_p-p (3 V) or 0 V to 2.5 V_p-p (5 V) input ranges-ideal for DSP front ends and mobile communication subsampling applications.

For engineers reviewing the AD7822BRZ datasheet, AD7822BRZ pinout, AD7822BRZ application, or AD7822BRZ equivalent, key selection considerations include its 2 MSPS throughput, channel-select-free operation, VMID-adjustable input span, EOC-driven standalone interfacing, and compatibility with microprocessor/DSP parallel buses without external timing logic.

Technical Context

The AD7822BRZ implements an 8-bit half-flash architecture: a 4-bit coarse flash ADC followed by a 4-bit fine flash stage, achieving full conversion in ≤420 ns. Its track-and-hold acquires input in ≤200 ns and supports full-power bandwidth up to 10 MHz, enabling accurate subsampling of RF-adjacent baseband signals.

Conversion is initiated by the falling edge of CONVST, which also places the T/H into hold mode; at end-of-conversion (EOC high), the state of CONVST determines automatic power-down entry. The device uses a single-pin combined convert-start/power-down control, with no separate PD pin-distinguishing it from AD7825/AD7829 variants.

Key Specifications

Pinout & Package

AD7822BRZ is housed in a 20-lead, 0.3" wide plastic dual in-line package (PDIP) with standard through-hole mounting. Pin functions are fully defined in 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 parallel ADC applications.

Compared with AD7825BRZ, AD7822BRZ offers simpler single-input interfacing and lower pin count, while MAX1186BCAP+ trades parallel simplicity for serial flexibility and marginally higher speed-neither is pin-compatible, and all require distinct PCB layout and firmware adaptation.

Availability

AD7822BRZ is available at Aetrix Electronics and suitable for disk drive servo control, mobile baseband subsampling, DSP front-end acquisition, industrial PLC analog input modules, and portable test equipment requiring stable component supply and long-term obsolescence management.

Supply support for AD7822BRZ 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 and manufacturing expertise spanning precision converters, amplifiers, and RF ICs.

The AD7822BRZ belongs to the AD7822/AD7825/AD7829 family of high-speed, microprocessor-compatible sampling ADCs designed specifically for real-time data acquisition, communications subsampling, and embedded DSP interfaces where low latency and deterministic timing are critical.

FAQ

What is the maximum sampling rate supported by the AD7822BRZ?

The AD7822BRZ 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 with either 3 V ±10% or 5 V ±10% supply. At 2 MSPS, the AD7822BRZ delivers consistent 8-bit resolution with no missing codes and maintains SNR ≥48 dB at 30 kHz input frequency.

Does the AD7822BRZ require an external reference voltage?

No, the AD7822BRZ includes an on-chip 2.5 V reference with ±50 mV accuracy and 50 ppm/°C temperature coefficient, accessible at the VREF IN/OUT pin. This reference is sufficient for most applications; however, an external precision reference (e.g., AD780) may be connected to VREF IN/OUT if tighter initial accuracy or lower drift is required. When using the internal reference, the pin may be left unconnected or decoupled to AGND with 0.1 µF.

How does automatic power-down work on the AD7822BRZ?

At the end of each conversion, when the EOC signal goes high, the AD7822BRZ samples the logic level on the CONVST pin. If CONVST is low at that instant, the device enters power-down mode, reducing supply current to ≤5 µA. This feature is enabled by default and requires no additional control lines-unlike AD7825/AD7829, the AD7822BRZ has no dedicated PD pin, making its power management fully pin-integrated and layout-efficient.

Can the AD7822BRZ interface directly with a 3.3 V microcontroller?

Yes, the AD7822BRZ is fully compatible with 3.3 V logic systems. Its digital inputs (CONVST, RD, CS, A0–A2) accept VIH ≥2.0 V and VIL ≤0.4 V at 3 V supply, and its outputs (EOC, DB0–DB7) drive VOH ≥2.4 V and VOL ≤0.2 V under 200 µA load-meeting standard 3.3 V CMOS/TTL thresholds. No level-shifting circuitry is needed when interfacing with 3.3 V microcontrollers such as ARM Cortex-M or PIC32 families.

What is the purpose of the VMID pin on the AD7822BRZ?

The VMID pin sets the centerpoint of the AD7822BRZ's analog input voltage range. With no connection, VMID defaults to 1.0 V (3 V supply) or 1.25 V (5 V supply), establishing a 0–2 V_p-p or 0–2.5 V_p-p input span centered at that voltage. Applying an external voltage to VMID shifts the entire input range linearly-enabling offset correction, single-supply op amp interface optimization, and rejection of system-level DC offsets without additional signal conditioning.