Analog Devices Inc. AD677BD

Overview

AD677BD from Analog Devices is a 16-bit, 100 kSPS autocalibrating successive-approximation ADC with serial output, ±10 V input range, –99 dB THD, and 92 dB S/(N+D), designed for precision measurement systems requiring high dc accuracy and dynamic performance in industrial temperature environments.

For engineers reviewing the AD677BD datasheet, AD677BD pinout, AD677BD application, or AD677BD equivalent, this page delivers verified specifications, ceramic DIP-16 package details, timing-critical interface guidance, and validated alternatives for embedded instrumentation, data acquisition, and automated test equipment design.

Technical Context

The AD677BD implements a switched-capacitor charge-redistribution SAR architecture with on-chip microcoded controller and dual-die construction (BiMOS II analog + DSP CMOS digital chip), enabling autocalibration of capacitor mismatch errors without external trims. It uses a 17-clock-cycle conversion sequence with aperture delay of 6 ns and jitter under 100 ps.

Its dual-supply architecture separates analog (±12 V) and digital (+5 V) domains, includes AGND sense for remote ground referencing, and supports twos-complement serial output synchronized to SCLK derived from CLK - all operating across –40°C to +85°C with ±1.5 LSB INL and 90 dB S/(N+D) minimum.

Key Specifications

Pinout & Package

AD677BD is housed in a 16-pin narrow ceramic DIP (D-16 package), rated for –40°C to +85°C operation, with hermetic sealing suitable for harsh industrial environments and long-term reliability in mission-critical instrumentation.

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 AD677BD provides unique value in legacy industrial systems requiring hermetic ceramic packaging, true bipolar ±10 V input, and autonomous autocalibration - features absent in newer monolithic SAR ADCs optimized for integration over ruggedness.

Availability

AD677BD is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, scientific data acquisition, and power quality analyzers requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for AD677BD 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 precision instrumentation, industrial automation, and communications markets since 1965.

The AD677BD belongs to Analog Devices' legacy high-accuracy SAR ADC product line, engineered specifically for applications demanding guaranteed dc linearity, low distortion, and robust operation in uncontrolled thermal environments - not merely high-speed sampling.

FAQ

What is the operating temperature range of the AD677BD?

The AD677BD is specified for continuous operation from –40°C to +85°C, matching the industrial temperature grade (B grade) defined in the Analog Devices ordering guide. This range applies to all electrical specifications including ±1.5 LSB INL, 90 dB S/(N+D), and full 100 kSPS throughput - confirmed in the DC and AC specifications tables for AD677K/B and AD677A/B variants. The ceramic DIP package ensures mechanical stability across this range.

Does the AD677BD require external calibration components?

No, the AD677BD does not require external calibration components. Its on-chip autocalibration circuitry - comprising a microcontroller, calibration DAC, and RAM storage - measures and corrects capacitor mismatch errors during each calibration cycle. As documented in the Functional Description section, this eliminates user trims, external resistors, or trimming potentiometers, making the AD677BD self-contained for dc accuracy maintenance.

How is the AGND SENSE pin used in practical circuit design?

The AGND SENSE pin (Pin 9) connects to the remote analog signal source's ground point - not the ADC's local AGND - to compensate for voltage drop across PCB traces or cables. In practice, this forms a Kelvin connection that cancels ground-loop offset errors. The AD677BD datasheet confirms its use in distributed sensor systems where signal integrity degrades due to shared return paths, and it must be routed separately from AGND to avoid defeating its purpose.

What are the critical timing constraints for reliable AD677BD conversion?

Three timing parameters are critical: (1) tFCD = 50 ns minimum delay between SAMPLE going LOW and first CLK edge; (2) tSL = 100 ns minimum SAMPLE low time; and (3) tC = 1000 µs maximum total conversion period (SAMPLE HIGH to 17th CLK completion). Violating tFCD causes misaligned sampling; exceeding tC risks capacitor leakage-induced error accumulation. These values are measured and guaranteed per the Timing Specifications table.

Can the AD677BD operate with a 5 V reference instead of 10 V?

Yes, the AD677BD supports VREF from 5 V to 10 V as specified in the DC Specifications table. At 5 V reference, the input range becomes ±5 V, power consumption drops to 360 mW (vs 450 mW at 10 V), and dynamic performance remains within spec - e.g., 89 dB S/(N+D) min and ±1.5 LSB INL still apply. However, Figure 11 shows S/(N+D) degrades slightly at lower references, so 10 V is preferred for maximum dynamic range.