Analog Devices Inc. AD677JD

Overview

AD677JD from Analog Devices is a 16-bit, 100 kSPS autocalibrating successive-approximation ADC with on-chip sample-hold, serial output, and ±10 V input range. It uses a switched-capacitor/charge-redistribution architecture across dual monolithic chips (analog BiMOS II + digital DSP CMOS), operates from ±12 V and +5 V supplies, and delivers 92 dB S/(N+D) and ±1 LSB INL (typ) for precision measurement and signal processing applications.

For engineers reviewing the AD677JD datasheet, AD677JD pinout, AD677JD application, or AD677JD equivalent, key selection considerations include its ceramic DIP-16 package, 0°C to +70°C commercial temperature grade, 89 dB min S/(N+D), ±1 LSB typical INL, and requirement for external 5–10 V reference voltage and precise timing control via SAMPLE/CLK signals.

Technical Context

The AD677JD implements a capacitor-array SAR architecture-not resistor-ladder-eliminating temperature-induced linearity drift. Its dual-die construction separates analog signal path (BiMOS II) from digital control logic (DSP CMOS), with dedicated AGND/DGND pins and AGND SENSE for remote ground referencing.

Autocalibration is performed in hardware using an on-chip microcontroller, calibration DAC, and RAM storage of correction coefficients for capacitor mismatch across the top nine bits. Calibration requires 85,532 clock cycles and is triggered asynchronously by the CAL pin, with BUSY indicating active calibration or conversion.

Key Specifications

Pinout & Package

AD677JD is housed in a 16-pin narrow side-brazed ceramic DIP (D-16 package), rated for 0°C to +70°C operation, with hermetic sealing suitable for high-reliability industrial environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD677KN and AD676JD, the AD677JD uniquely combines ceramic DIP reliability, serial interface simplicity, and typ ±1 LSB INL - making it optimal for space-constrained, high-stability measurement systems where serial data reduction and hermetic integrity are prioritized.

Availability

AD677JD is available at Aetrix Electronics and suitable for precision data acquisition, industrial process monitoring, and communications signal analysis requiring stable component supply, long-term obsolescence management, and traceable sourcing from authorized channels.

Supply support for AD677JD 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 AD677JD belongs to Analog Devices' precision SAR ADC product line, engineered for applications demanding high dc accuracy, low distortion, and integrated calibration - especially in test & measurement, industrial automation, and medical instrumentation.

FAQ

What is the operating temperature range for the AD677JD?

The AD677JD is specified for commercial operation from 0°C to +70°C. This grade is validated per the AD677 ordering guide and applies to the ceramic DIP-16 (D-16) package variant. It does not support extended industrial (–40°C to +85°C) operation - for that range, the AD677AD or AD677BD should be selected. All timing, INL, and dynamic specifications in the datasheet for AD677JD are guaranteed within this 0°C to +70°C window.

Does the AD677JD require an external voltage reference?

Yes, the AD677JD requires an external precision voltage reference applied to the VREF pin. It accepts 5 V to 10 V inputs, defining the ±VREF full-scale range. The device does not include an internal reference; reference stability and noise directly impact gain error and SNR. For best performance, a low-drift, low-noise reference such as the AD589 or ADR03 is recommended, with proper decoupling per Figure 4 in the AD677 datasheet.

How is calibration performed on the AD677JD?

Calibration on the AD677JD is initiated by driving the CAL pin HIGH (asynchronous reset), then LOW. This triggers an 85,532-clock-cycle autocalibration sequence that measures and corrects capacitor mismatch errors in the top nine bits. During calibration, BUSY goes HIGH and remains asserted until completion. No external intervention is needed - coefficients are stored in on-chip RAM and automatically applied to subsequent conversions. Calibration is typically done once at power-up after supplies stabilize.

What are the critical timing requirements for initiating a conversion on the AD677JD?

To initiate a valid conversion on the AD677JD, SAMPLE must be held HIGH for ≥2 µs (sampling time), then brought LOW. After a 50 ns delay (tFCD), exactly 17 CLK pulses must be applied. The total conversion period must not exceed 1000 µs from SAMPLE HIGH to end of 17th CLK pulse. Violating tFCD or exceeding tC degrades INL and dynamic performance. BUSY indicates active conversion and must be monitored for handshaking in continuous mode.

Can the AD677JD interface directly with a microcontroller's SPI port?

The AD677JD does not support standard SPI protocol - it outputs serial data (SDATA) and a derived clock (SCLK), but SCLK is not freely programmable and is synchronized to the master CLK input. Microcontrollers must bit-bang the interface using GPIOs to control SAMPLE, CLK, and read SDATA on SCLK edges. No native SPI mode or frame synchronization is provided; timing must strictly follow Figures 1 and 2 in the AD677 datasheet to avoid data corruption.