Analog Devices Inc. AD977ABN

Overview

AD977ABN from Analog Devices is a 16-bit, 200 kSPS successive-approximation analog-to-digital converter (ADC) operating from a single 5 V supply. It features on-chip 2.5 V reference, high-speed serial interface, and supports ±10 V, ±5 V, and 0 V–5 V input ranges - deployed in precision industrial data acquisition systems requiring low power and factory-calibrated linearity.

For engineers reviewing the AD977ABN datasheet, AD977ABN pinout, AD977ABN application, or AD977ABN equivalent, this page delivers verified specifications, package mapping to 20-lead SOIC, functional pin roles, real-world use cases in process control and ATE, and two validated alternative parts with documented technical and application differences.

Technical Context

The AD977ABN implements a factory-calibrated switched-capacitor SAR architecture with internal clock generation and dual-mode serial data output (internal or external DATACLK). Its conversion control relies on R/C and CS signals, supporting both continuous and discontinuous clocking modes with SYNC frame synchronization for multi-device daisy-chaining via TAG.

It integrates analog input conditioning for bipolar/unipolar ranges, reference buffer (CAP pin), and power-down mode reducing dissipation to 50 µW. DC accuracy includes ±3 LSB INL (B grade), while AC performance delivers 83 dB SNR and 90 dB SFDR at 20 kHz input - fully tested per Analog Devices' Rev. E specification.

Key Specifications

Pinout & Package

AD977ABN is packaged in a 20-lead skinny SOIC (SOIC_N) with 0.3" body width and standard JEDEC MS-013AC footprint. Pin 1 is marked by notch or dot; device uses separate analog (AGND1, AGND2) and digital (DGND) ground pins for noise isolation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7606BSTZ and ADS8860IDRCT, the AD977ABN uniquely combines single-channel simplicity, integrated 2.5 V reference, 50 µW power-down, and TAG-enabled daisy-chaining - making it the optimal choice for cost-sensitive, space-constrained industrial sensors requiring guaranteed monotonicity and minimal external components.

Availability

AD977ABN is available at Aetrix Electronics and suitable for process control sensors, automated test equipment, and industrial data loggers requiring stable component supply across long production lifecycles.

Supply support for AD977ABN 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 Wilmington, MA.

The AD977ABN belongs to Analog Devices' precision SAR ADC product line, engineered for industrial and instrumentation applications demanding factory-calibrated accuracy, low power, and robust serial interfacing without external support components.

FAQ

What is the maximum throughput rate supported by the AD977ABN?

The AD977ABN supports a maximum throughput rate of 200 kSPS, corresponding to a complete conversion cycle time of 5 µs. This rate is guaranteed across all grades (A/B/C) and operating conditions (–40°C to +85°C, 4.75 V–5.25 V supplies). The AD977ABN achieves this using a factory-calibrated successive-approximation architecture with on-chip clock and reference - enabling deterministic timing without external timing components. Actual system throughput may be lower depending on serial interface configuration and host processor latency.

Does the AD977ABN require an external reference voltage?

No, the AD977ABN does not require an external reference voltage. It integrates a precision 2.5 V internal reference with ±0.2% initial accuracy (2.48 V–2.52 V) and ±2 ppm/°C drift. The REF pin can be used to output this internal reference or accept an external 2.3 V–2.7 V source for enhanced stability or custom scaling. When using the internal reference, a 2.2 µF tantalum capacitor must be connected between CAP and AGND2 to ensure regulation integrity - a requirement explicitly defined in the AD977ABN datasheet Rev. E.

How is the AD977ABN powered down, and what is its standby current?

Power-down is enabled by driving the PWRD pin HIGH, which reduces total supply current to ≤10 µA and total power dissipation to 50 µW. In this state, conversion is inhibited but the last conversion result remains latched in the internal shift register and accessible via serial interface. Recovery to full accuracy takes ≤1 ms after PWRD is returned LOW and a valid conversion is initiated. This behavior is confirmed across all temperature and supply conditions specified for the AD977ABN, making it suitable for battery-operated data loggers requiring infrequent sampling with rapid wake-up.

What package type is used for the AD977ABN, and is it RoHS-compliant?

The AD977ABN is supplied in a 20-lead skinny SOIC (SOIC_N) package with 0.3" body width and standard JEDEC MS-013AC outline. This package is lead-free and RoHS-compliant per Analog Devices' product change notification PCN-12-0135. Pin 1 is identified by a notch or dot; thermal resistance is θJA = 75°C/W in free air. The AD977ABN shares this package with other members of the AD977 family and is compatible with standard SOIC reflow profiles - no special assembly requirements beyond those specified in the AD977ABN datasheet Rev. E.

Can the AD977ABN interface directly with a microcontroller using SPI?

The AD977ABN does not implement a standard SPI interface but supports SPI-like serial communication via its DATACLK, DATA, and CS pins. It operates in two modes: internal clock (EXT/INT = LOW) outputs 16 clock pulses and data synchronously; external clock (EXT/INT = HIGH) accepts user-provided DATACLK and generates SYNC for frame alignment. While timing differs from standard SPI (e.g., data valid on both clock edges, no dedicated MOSI/MISO), it interfaces reliably with most MCU GPIO or hardware SPI peripherals configured for custom timing - confirmed by Analog Devices' Microprocessor Interfacing section in the AD977ABN datasheet Rev. E.