Analog Devices Inc. AD7884APZ

Overview

AD7884APZ from Analog Devices is a 16-bit monolithic sampling analog-to-digital converter (ADC) with internal sample-and-hold, 5.3 µs conversion time, ±5 V or ±3 V input ranges, and 16-bit parallel output. It operates from ±5 V supplies with a 3 V reference and is used in high-speed data acquisition systems requiring precision and throughput.

For engineers reviewing the AD7884APZ datasheet, AD7884APZ pinout, AD7884APZ application, or AD7884APZ equivalent, key selection criteria include its 166 kSPS throughput, twos complement output coding, bipolar zero error of ±0.15% FSR max, and compatibility with microprocessor interfaces via CS/RD control signals.

Technical Context

The AD7884APZ implements a two-pass flash architecture: first pass captures 9 MSBs using a 9-bit ADC and 16-bit DAC, second pass digitizes the residue amplified error signal to generate the full 16-bit result. Conversion is initiated asynchronously by CONVST, with BUSY signaling active-low during conversion.

It features separate analog (AVDD/AVSS) and digital (VDD/VSS) supply domains, dedicated AGNDS/AGNDF force-sense ground paths for the 9-bit ADC section, and on-chip oscillator control - eliminating external timing components. Input conditioning supports selectable ±5 V or ±3 V ranges via dedicated force/sense pins (±5VINF/±5VINS or ±3VINF/±3VINS).

Key Specifications

Pinout & Package

The AD7884APZ is packaged in a 44-lead plastic leaded chip carrier (PLCC), P-44A, with gull-wing leads and pin 1 identifier marked on top surface. Thermal impedance θ_JA = 47.7°C/W, θ_JC = 17.5°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7884AQ, AD7884APZ offers identical electrical performance in a space-efficient PLCC package with better thermal dissipation; compared with AD7885AAP, it provides true 16-bit parallel access without timing overhead or additional control lines.

Availability

AD7884APZ is available at Aetrix Electronics and suitable for automatic test equipment, medical instrumentation, and industrial control systems requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for AD7884APZ 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 AD7884 product line was designed for high-speed, high-accuracy data acquisition in demanding industrial and instrumentation applications where 16-bit resolution, fast throughput, and robust analog input conditioning are essential.

FAQ

What is the maximum sampling rate supported by the AD7884APZ?

The AD7884APZ supports a maximum throughput rate of 166 kSPS, achieved through overlapped conversion and acquisition phases. This is enabled by its two-pass flash architecture and internal timing control - no external clock is needed. The 5.3 µs conversion time is fixed, and the 166 kSPS rate assumes minimal inter-conversion dead time. Actual system-level throughput may vary depending on microprocessor bus timing and RD/CS assertion delays.

Does the AD7884APZ require an external reference voltage?

No, the AD7884APZ operates from an internal 3 V reference derived from the VREF+S and VREF+F pins. A precision external 3 V reference (e.g., AD780) must be connected to these pins - the device does not generate its own reference. The datasheet specifies that VREF+S is the sense input and VREF+F is the force input; both must be driven by a low-noise, low-impedance source to maintain 84 dB SNR and ±0.0075% FSR INL.

How is the analog input range selected on the AD7884APZ?

The AD7884APZ supports hardware-selectable ±5 V or ±3 V input ranges via dedicated pin strapping: for ±5 V, connect ±5VINF and ±5VINS to the signal source and tie ±3VINF/±3VINS to AGND; for ±3 V, reverse the connections. No register writes or timing sequences are involved - range selection is purely physical. The input stage uses matched on-chip resistors (R1–R8) to condition the signal before the 9-bit ADC, ensuring gain accuracy and tracking.

What is the function of the AGNDS and AGNDF pins on the AD7884APZ?

The AGNDS (analog ground sense) and AGNDF (analog ground force) pins form a Kelvin connection for the 9-bit ADC's ground return path. AGNDS senses the local ground potential at the ADC core, while AGNDF is driven by an external buffer (e.g., AD817) to maintain zero potential. If tied directly together and to system ground, INL degrades - the datasheet confirms dc specifications like bipolar zero and gain error suffer without buffering. These pins are not interchangeable with DGND or GND.

Can the AD7884APZ interface directly with a 3.3 V microcontroller?

No, the AD7884APZ is not 3.3 V compatible: its digital inputs require VINH ≥ 2.4 V (min) and VINL ≤ 0.8 V (max) under VDD = +5 V ±5%, and its DB0–DB15 outputs swing from 0.4 V to 4.0 V - exceeding 3.3 V logic thresholds. Direct connection risks damage or misreads. Level translation (e.g., SN74LVC4245) or a 5 V-tolerant microcontroller interface is required. The device draws IDD = 33 mA max and ISS = 33 mA max, so power supply design must accommodate ±5 V at ~66 mA total.