Analog Devices Inc. AD976BR

Overview

AD976BR from Analog Devices is a 16-bit, 100 kSPS BiCMOS successive-approximation analog-to-digital converter with ±10 V input range, internal 2.5 V reference, and parallel 16-bit twos-complement output - designed for precision industrial data acquisition systems requiring high DC accuracy and moderate sampling speed.

For engineers reviewing the AD976BR datasheet, AD976BR pinout, AD976BR application, or AD976BR equivalent, this page delivers verified technical context, real-world timing behavior, package-specific interface constraints, and validated alternative options for legacy system maintenance and board-level replacement.

Technical Context

The AD976BR implements a switched-capacitor SAR architecture with on-chip laser-trimmed capacitor array calibration, eliminating external sample-and-hold circuitry. It uses factory-stored thin-film resistor coefficients to correct capacitor mismatch errors in real time during conversion.

It supports dual-mode digital control via R/C and CS pins - enabling either autonomous conversion triggering (CS tied low) or synchronized read/conversion sequencing (CS pulsed). The BYTE pin allows flexible 16-bit data access as full-word or two 8-bit bytes on dedicated pin groups.

Key Specifications

Pinout & Package

AD976BR is housed in a 28-lead Small Outline Integrated Circuit (SOIC) package (R-28), 300 mil width, with gull-wing leads and standard JEDEC MS-012AC footprint. Thermal resistance θ_JA = 72°C/W enables operation up to +85°C ambient without forced airflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD976BR, AD976AR trades 1 LSB of INL and 2 dB of S/(N+D) for lower unit cost, while ADS8688IPWR offers higher speed and signal conditioning at the expense of pin compatibility and increased design effort.

Availability

AD976BR is available at Aetrix Electronics and suitable for industrial process monitoring, test equipment calibration, legacy control system upgrades, and embedded data loggers requiring stable component supply across long production lifecycles.

Supply support for AD976BR 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 digital signal processing semiconductors, serving industrial, communications, and automotive markets since 1965.

The AD976 family was engineered for precision data acquisition in resource-constrained industrial environments - emphasizing single-supply operation, integrated calibration, and robustness against ESD and overvoltage events.

FAQ

What is the maximum sampling rate supported by the AD976BR?

The AD976BR supports a maximum throughput rate of 100 kSPS, corresponding to a fixed 10 µs conversion cycle time. This is confirmed in the AD976–SPECIFICATIONS table under "THROUGHPUT SPEED" and applies across all grades (A/B/C) and packages including the R-28 SOIC variant used in AD976BR. The AD976BR does not support the 200 kSPS mode - that is exclusive to AD976A variants.

Does the AD976BR require external calibration components?

No, the AD976BR does not require external calibration components for baseline operation. It features factory-trimmed capacitor array calibration and stored correction coefficients. External resistors (e.g., 200 Ω on VIN, 33.2 kΩ on REF) are only needed if fine-tuning offset/gain beyond datasheet limits - and even then, Figure 7 shows they are optional. The AD976BR achieves ±2 LSB INL (B-grade) without them.

Can the AD976BR operate with an external reference voltage?

Yes, the AD976BR supports external reference voltages between 2.3 V and 2.7 V applied to the REF pin, overriding the internal 2.5 V reference. When using an external reference, the internal reference source current (1 µA) is disabled, and the external source must sink up to 100 µA. Full specified linearity is guaranteed only within this 2.3–2.7 V window.

What is the purpose of the CAP pin on the AD976BR?

The CAP pin on the AD976BR is the output of the internal reference buffer and must be decoupled to AGND2 with a 2.2 µF tantalum capacitor. This stabilizes the reference voltage during conversion cycles and prevents noise coupling into the analog core. Omitting this capacitor causes reference droop and degrades INL and S/(N+D) performance - it is not optional per the Functional Description and Pin Function Descriptions sections.

Is the AD976BR pin-compatible with other AD976 variants in SOIC packages?

Yes, the AD976BR is fully pin-compatible with all AD976xR variants (e.g., AD976AR, AD976CR) in the 28-lead SOIC (R-28) package. Pin numbering, function mapping, and mechanical footprint match exactly per the PIN CONFIGURATION diagram and ORDERING GUIDE. Differences exist only in grade-spec performance (INL, S/(N+D)), not interface or connectivity.