Analog Devices Inc. AD977ARS

Overview

AD977ARS from Analog Devices is a 16-bit, 100 kSPS successive-approximation analog-to-digital converter (ADC) operating from a single 5 V supply. It features factory-calibrated linearity, ±10 V/±5 V/±3.3 V bipolar and 0 V–10 V/0 V–5 V/0 V–4 V unipolar input ranges, on-chip 2.5 V reference, and high-speed serial interface - deployed in precision industrial data acquisition systems requiring stable dc accuracy and low power.

For engineers reviewing the AD977ARS datasheet, AD977ARS pinout, AD977ARS application, or AD977ARS equivalent, this page delivers verified specifications, SOIC-20 package mapping, real-world timing behavior, and validated alternative options for process control, ATE, and embedded sensor signal chains.

Technical Context

The AD977ARS implements a switched-capacitor SAR architecture with internal clock generation and serial data output synchronized to either internal or external DATACLK. Its conversion control relies on R/C and CS signals, supporting both continuous and discontinuous clock modes with SYNC frame alignment when EXT/INT = HIGH.

It integrates a 2.5 V internal reference (±2 mV initial tolerance, ±2 ppm/°C drift) and supports external reference inputs from 2.3 V to 2.7 V. Power-down mode reduces dissipation to 50 µW while preserving the last conversion result in the shift register.

Key Specifications

Pinout & Package

AD977ARS is supplied in a 20-lead Skinny SOIC (SOIC-20) package with standard JEDEC MS-013AC footprint (7.5 mm × 12.8 mm, 1.27 mm pitch). Thermal resistance θ_JA = 75°C/W enables operation up to +85°C ambient with minimal heatsinking.

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 AD977ARS offers unique value in single-channel industrial DAQ where internal reference, bipolar/unipolar flexibility, and proven 100 kSPS accuracy at 100 mW are prioritized over channel count or speed.

Availability

AD977ARS is available at Aetrix Electronics and suitable for process control sensor monitoring, automated test equipment, and embedded data acquisition requiring stable component supply, long-lifecycle support, and traceable manufacturing history.

Supply support for AD977ARS 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, automotive, and consumer markets since 1965.

The AD977ARS belongs to Analog Devices' precision SAR ADC product line, designed specifically for applications demanding high dc accuracy, low power, and flexible analog input configuration in harsh industrial environments.

FAQ

What is the maximum throughput rate supported by the AD977ARS?

The AD977ARS supports a maximum throughput rate of 100 kSPS, corresponding to a complete conversion cycle time of 10 µs. This is confirmed in the AD977–Specifications table (Rev. E, p.3) and applies across all grade options (A/B/C) over the full –40°C to +85°C operating range. The AD977ARS is distinct from the faster AD977A variant, which achieves 200 kSPS.

Does the AD977ARS include an internal voltage reference?

Yes, the AD977ARS integrates a precision 2.5 V internal reference with ±2 mV initial tolerance and ±2 ppm/°C drift over temperature. As documented in Table 1 (p.4) and Pin Function Descriptions (p.9), this reference is accessible at the REF pin and can be overridden by an external 2.3–2.7 V source. A 2.2 µF tantalum capacitor must be placed between CAP and AGND2 for stability.

Which package type is used for the AD977ARS?

The AD977ARS is packaged in a 20-lead Skinny SOIC (SOIC-20) outline, as specified in the Ordering Guide (p.32) and Pin Configuration diagrams (Fig. 3, p.9). This package has a 1.27 mm lead pitch, 7.5 mm × 12.8 mm body size, and thermal resistance θ_JA = 75°C/W - distinct from the 28-lead SSOP option offered for the same AD977 family.

Can the AD977ARS operate with bipolar input ranges?

Yes, the AD977ARS supports bipolar input ranges of ±10 V, ±5 V, and ±3.3 V, as explicitly stated in the General Description (p.1) and AD977–Specifications tables (p.3). These ranges are configured using external resistor networks per Figure 14–16, and bipolar zero error is specified at ±10–15 mV depending on grade - enabling direct interfacing with industrial transducers without level-shifting circuitry.

How does the power-down mode function on the AD977ARS?

The AD977ARS enters power-down mode when the PWRD pin is driven HIGH, reducing total power dissipation to 50 µW (10 µA supply current). As described in the Features list (p.1) and Specifications table (p.6), the last conversion result remains latched in the internal shift register and is available immediately upon exit from power-down - enabling rapid wake-up sampling in battery-powered applications.