Analog Devices Inc. AD977BRSZ

Overview

AD977BRSZ 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, 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 stable dc accuracy and low power.

For engineers reviewing the AD977BRSZ datasheet, AD977BRSZ pinout, AD977BRSZ application, or AD977BRSZ equivalent, this page delivers verified specifications, real-world timing behavior, package-specific terminal mapping, and validated alternative options for embedded measurement and control designs.

Technical Context

The AD977BRSZ implements a 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, with BUSY indicating active conversion and pipeline delay ensuring result availability only after completion.

It supports both binary two's complement and straight binary output formats via SB/BTC, and uses AGND1/AGND2 separation to minimize analog-digital coupling. Reference flexibility includes internal 2.5 V ±20 mV or external 2.3 V–2.7 V sources, buffered through CAP with 2.2 µF tantalum.

Key Specifications

Pinout & Package

AD977BRSZ 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; leads are gull-wing, 0.025" pitch.

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 AD977BRSZ uniquely combines factory-calibrated 16-bit linearity, internal reference, bipolar/unipolar configurability, and 50 µW power-down - making it the preferred choice for cost-sensitive, single-channel, low-power industrial DAQ where timing determinism and dc stability outweigh raw speed.

Availability

AD977BRSZ is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, medical instrumentation, and energy metering reference designs requiring stable component supply and long-term obsolescence management.

Supply support for AD977BRSZ 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, automotive, communications, and healthcare markets since 1965.

The AD977BRSZ belongs to Analog Devices' precision SAR ADC product line, engineered for applications demanding guaranteed dc accuracy, low power, and simplified system integration - especially where factory calibration replaces field tuning.

FAQ

What is the maximum sampling rate supported by the AD977BRSZ?

The AD977BRSZ supports a maximum throughput rate of 100 kSPS, corresponding to a complete conversion cycle time of 10 µs. This is specified for all grade options (A/B/C) across the full –40°C to +85°C operating range and is independent of input range selection or reference configuration. The AD977BRSZ achieves this rate using its internal successive-approximation architecture and on-chip clock generator, with BUSY signal deassertion marking result readiness for serial readout.

Does the AD977BRSZ include an internal voltage reference?

Yes, the AD977BRSZ integrates a 2.5 V internal reference with ±20 mV initial tolerance (2.48 V to 2.52 V) and ±2 ppm/°C drift over temperature. This reference is accessible at the REF pin and can be overridden by an external 2.3 V–2.7 V source. A 2.2 µF tantalum capacitor must be placed between REF and AGND2, and CAP must be similarly decoupled to AGND2, to maintain stability and achieve specified linearity and noise performance.

How does the AD977BRSZ handle power-down mode?

The AD977BRSZ enters power-down mode when the PWRD pin is driven logic HIGH, reducing supply current to 50 µW while preserving the last conversion result in its internal shift register. Recovery to full accuracy requires 1 ms after PWRD returns LOW and an external 2.2 µF capacitor is connected to CAP. During power-down, conversions are inhibited but the device retains configuration state - enabling rapid wake-up in battery-powered data loggers without reinitialization overhead.

Can the AD977BRSZ interface directly to an FPGA without level-shifting?

Yes, the AD977BRSZ digital interface operates at 5 V logic levels (VIH = 2.0 V min, VOH = 4.0 V min at 500 µA), matching standard 5 V CMOS FPGA I/O banks. Its DATA, DATACLK, and BUSY outputs drive compatible loads, and inputs like R/C, CS, and EXT/INT accept 0 V/5 V signals directly. No level-shifting is needed when interfacing with 5 V-tolerant FPGA pins; however, proper decoupling and ground separation (DGND/AGND) must be maintained per layout guidelines in the datasheet to preserve SNR.

What input voltage ranges does the AD977BRSZ support?

The AD977BRSZ supports six factory-characterized input ranges: bipolar ±10 V, ±5 V, ±3.3 V and unipolar 0 V–10 V, 0 V–5 V, and 0 V–4 V. Range selection is accomplished externally using resistor networks connected to R1IN/R2IN/R3IN per Table 8 in the datasheet - no internal register writes or digital configuration is required. Each range maintains full 16-bit resolution and specified INL/DNL performance across temperature.