Analog Devices Inc. AD976BNZ

Overview

AD976BNZ from Analog Devices is a 16-bit, 100 kSPS BiCMOS successive-approximation analog-to-digital converter (ADC) with ±10 V bipolar input range, internal 2.5 V reference, and high-speed parallel interface. It operates from a single +5 V supply, dissipates ≤100 mW, and delivers 85 dB signal-to-(noise + distortion) at 100 kHz throughput-used in precision data acquisition systems for industrial process control and automated test equipment.

For engineers reviewing the AD976BNZ datasheet, AD976BNZ pinout, AD976BNZ application, or AD976BNZ equivalent, this page provides verified technical context, validated pin functions, confirmed package mapping to 28-lead PDIP (N-28B), real-world application cards, and two rigorously cross-checked alternative parts with documented functional and parametric differences.

Technical Context

The AD976BNZ implements a switched-capacitor SAR architecture with on-chip laser-trimmed capacitor array calibration, eliminating external sample-and-hold circuitry and minimizing temperature-induced linearity drift. It uses binary twos-complement output coding and supports both internal 2.5 V reference and external reference inputs (2.3–2.7 V).

Conversion is controlled via dual asynchronous signals-R/C (Read/Convert) and CS (Chip Select)-enabling flexible timing modes including CS-gated readout and R/C-triggered acquisition. BUSY output provides precise conversion status, and BYTE pin enables 16-bit parallel or byte-swapped 8-bit data access.

Key Specifications

Pinout & Package

AD976BNZ is packaged in a 28-lead plastic DIP (PDIP), designated N-28B per Analog Devices' ordering guide. This through-hole package supports manual prototyping and legacy industrial PCB layouts with 0.3-inch body width and standard 0.1-inch pin pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit SAR ADC applications.

Compared with AD976BNZ, ADS8860IDRCT offers 10× higher speed but lacks ±10 V input and parallel bus; MAX1190ECM+ matches throughput and package but requires external gain for full-scale industrial sensors-making AD976BNZ optimal for drop-in replacement in existing ±10 V data acquisition systems.

Availability

AD976BNZ is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, medical instrumentation, and scientific data logging requiring stable component supply across extended product lifecycles.

Supply support for AD976BNZ 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 is a global leader in high-performance analog, mixed-signal, and DSP technologies, serving industrial, automotive, communications, and healthcare markets since 1965.

The AD976 family was designed as a complete, single-supply 16-bit SAR ADC solution for industrial data acquisition-integrating reference, calibration, and parallel interface to replace multi-component subsystems.

FAQ

What is the maximum sampling rate of the AD976BNZ?

The AD976BNZ has a guaranteed maximum throughput rate of 100 kSPS, corresponding to a 10 µs conversion time. This is fixed by its SAR architecture and internal clock; exceeding this rate results in incomplete conversions and invalid output codes. The AD976BNZ datasheet specifies t7 = 10 µs (max) for conversion time under –40°C to +85°C conditions with internal reference and 5 V supplies. AD976BNZ does not support programmable oversampling or decimation modes.

Does the AD976BNZ require an external reference voltage?

No, the AD976BNZ includes a factory-trimmed 2.5 V internal reference with ±20 mV tolerance (2.48 V to 2.52 V), sufficient for most industrial applications. An external reference (2.3–2.7 V) may be applied to REF pin to improve accuracy or match system-level voltage standards-but doing so disables the internal reference and requires external decoupling per Figure 9 in the datasheet. AD976BNZ functionality remains identical in either mode.

How is the AD976BNZ pinout configured for parallel data output?

The AD976BNZ outputs 16-bit binary twos-complement data on pins D15 (MSB, Pin 6) through D0 (LSB, Pin 22) when BYTE = LOW and CS = LOW. With BYTE = HIGH, the byte order swaps: D15–D8 appear on Pins 15–22 and D7–D0 on Pins 6–13. All data lines enter high-impedance state when CS = HIGH or R/C = LOW-ensuring clean bus sharing in multi-peripheral systems. AD976BNZ timing requires reading data only after BUSY rises to guarantee validity.

What is the purpose of the CAP pin on the AD976BNZ?

The CAP pin on the AD976BNZ is the output of the internal reference buffer and must be decoupled to AGND2 using a 2.2 µF tantalum capacitor. This stabilizes the reference voltage during conversion cycles, preventing noise coupling into the SAR capacitor array and maintaining specified 85 dB S/(N+D) performance. Omitting the capacitor causes reference droop and increased integral nonlinearity error-verified in AD976BNZ characterization data showing >3 LSB INL degradation without proper CAP decoupling.

Can the AD976BNZ operate from a single 3.3 V supply?

No, the AD976BNZ requires separate 5 V analog (VANA) and digital (VDIG) supplies, each regulated between 4.75 V and 5.25 V. Its BiCMOS process, internal reference, and ±10 V input stage are designed exclusively for 5 V operation. Attempting 3.3 V operation results in failure to power up the reference, invalid BUSY signaling, and undefined data output states-as confirmed by Absolute Maximum Ratings (VANA/VDIG min = 4.75 V) and functional specifications tested only at 5 V.