Analog Devices Inc. AD977ARZ

Overview

AD977ARZ 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, ±3.3 V bipolar and 0 V–10 V/5 V/4 V unipolar input ranges - used in precision industrial data acquisition systems requiring stable dc accuracy and low power.

For engineers reviewing the AD977ARZ datasheet, AD977ARZ pinout, AD977ARZ application, or AD977ARZ equivalent, this page delivers verified technical context, real-world timing behavior, confirmed package mapping to 20-lead SOIC, and validated alternative options for system-level ADC selection and replacement planning.

Technical Context

The AD977ARZ 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, with BUSY indicating active conversion and pipeline delay ensuring results are only available after completion.

It supports dual data formats (Binary Two's Complement or Straight Binary) via SB/BTC, daisy-chain capability via TAG, and flexible reference configuration (internal 2.48–2.52 V or external 2.3–2.7 V). Power-down mode reduces consumption to 50 µW while preserving the last conversion result in the shift register.

Key Specifications

Pinout & Package

AD977ARZ is packaged in a 20-lead narrow-body SOIC (SOIC_N) with standard JEDEC MS-013AC footprint (body width 0.150", lead pitch 0.050"). Pin functions are electrically and mechanically validated per Analog Devices Rev. E datasheet Figures 3 and Table 6.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7606C-16 and ADS8860, the AD977ARZ offers unique value in single-channel, bipolar-input, self-clocked 100 kSPS applications where board space, component count, and factory-calibrated dc accuracy are prioritized over channel density or raw speed.

Availability

AD977ARZ is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, medical instrumentation, and energy metering calibration requiring stable component supply and long-term obsolescence management.

Supply support for AD977ARZ 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, serving industrial, automotive, communications, and healthcare markets.

The AD977 product line was designed specifically for precision, low-power, single-supply data acquisition in space- and cost-constrained industrial systems - emphasizing factory-trimmed dc accuracy, integrated reference, and simplified serial interface.

FAQ

What is the maximum sampling rate supported by the AD977ARZ?

The AD977ARZ supports a maximum throughput rate of 100 kSPS, corresponding to a complete conversion cycle time of 10 µs. This is specified across all grade options (A/B/C) and operating conditions (–40°C to +85°C, 5 V supply). The AD977ARZ achieves this with guaranteed 16-bit resolution, ±3 LSB integral nonlinearity, and full ac performance including 83 dB SNR and 90 dB SFDR at 20 kHz input frequency.

Does the AD977ARZ require an external reference voltage?

No, the AD977ARZ does not require an external reference voltage. It integrates a factory-trimmed 2.5 V reference (2.48 V to 2.52 V) accessible at the REF pin. An external reference (2.3 V to 2.7 V) may be used instead to improve long-term stability or match system-level reference standards, but the internal reference is fully functional and specified for all performance parameters in the datasheet.

Which package type is used for the AD977ARZ?

The AD977ARZ uses a 20-lead narrow-body SOIC package (SOIC_N), also designated as "R" in Analog Devices' ordering guide. Its mechanical outline conforms to JEDEC MS-013AC: 0.150" body width, 0.050" lead pitch, and gull-wing lead form. This package is distinct from the 28-lead SSOP (RS) variant and is explicitly listed for the AD977ARZ part number in the official datasheet ordering table.

How does the AD977ARZ handle power-down mode?

In power-down mode (PWRD = HIGH), the AD977ARZ reduces power dissipation to 50 µW while retaining the most recent conversion result in its internal shift register. The analog core and reference buffer are disabled, but the digital interface remains accessible - allowing wake-up and immediate readout of the stored result without re-conversion delay. Recovery to full accuracy takes ≤1 ms when external 2.2 µF capacitor is used on CAP.

Can the AD977ARZ interface directly with an FPGA using SPI protocol?

Yes, the AD977ARZ can interface directly with an FPGA using its native high-speed serial interface, though it is not a standard SPI-compliant device. It outputs MSB-first 16-bit data on the DATA pin synchronized to DATACLK edges (rising/falling depending on mode), with frame sync via SYNC when EXT/INT = HIGH. FPGAs must implement custom logic to sample DATA on correct clock edges and manage R/C/CS handshaking - no SPI mode register or standard CPOL/CPHA configuration is present.