Analog Devices Inc. AD677-EB

Overview

AD677-EB from Analog Devices is a 16-bit, 100 kSPS autocalibrating successive-approximation analog-to-digital converter (ADC) with integrated sample-and-hold, serial output, and dual-chip BiMOS II/CMOS architecture. It delivers ±1 LSB INL (typ), –99 dB THD, 92 dB S/(N+D), 1 MHz full-power bandwidth, and operates from ±12 V analog and +5 V digital supplies. It is used in precision instrumentation, data acquisition systems, and industrial measurement where dc accuracy and dynamic performance are co-required.

For engineers reviewing the AD677-EB datasheet, AD677-EB pinout, AD677-EB application, or AD677-EB equivalent, this page provides verified technical context, real-world timing constraints (e.g., 10 µs conversion time, 85,532-clock calibration cycle), package-specific pin mapping (16-pin DIP), and validated alternative options for signal chain design continuity.

Technical Context

The AD677-EB implements a switched-capacitor charge-redistribution SAR architecture with on-chip microcoded controller and separate analog (BiMOS II) and digital (CMOS) die. Calibration uses an internal DAC and RAM-stored correction coefficients to null capacitor mismatch and offset errors across temperature.

It requires 17 master clock (CLK) pulses per conversion, outputs twos-complement serial data via SDATA synchronized to SCLK, and uses dedicated AGND/AGND SENSE and DGND pins to isolate analog and digital return paths-critical for maintaining 16-bit linearity in mixed-signal PCB layouts.

Key Specifications

Pinout & Package

AD677-EB is supplied in a 16-pin 0.3" narrow-body plastic DIP (N-16 package). Pin functions are electrically identical to AD677JN/KN but configured for evaluation board interface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7606-4 and ADS8860, the AD677-EB provides unique autocalibration stability and true bipolar input capability at 100 kSPS-making it irreplaceable in legacy or calibration-critical measurement systems where long-term dc accuracy cannot rely on external firmware compensation.

Availability

AD677-EB is available at Aetrix Electronics and suitable for precision instrumentation, industrial process monitoring, and audio test equipment requiring stable component supply across extended product lifecycles.

Supply support for AD677-EB 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 AD677 product line was designed specifically for high-accuracy, medium-speed data acquisition in environments where both dc precision (±1 LSB INL) and ac fidelity (–99 dB THD) must coexist without user calibration intervention.

FAQ

What is the function of the AGND SENSE pin on the AD677-EB?

The AGND SENSE pin on the AD677-EB provides a dedicated connection point to remotely sense the analog ground potential at the signal source. This allows the AD677-EB to compensate for voltage drops across PCB traces or cables between the signal origin and the ADC, reducing common-mode error. It is especially valuable in systems with long analog interconnects, such as industrial sensor networks, and must be tied directly to the local AGND at the signal source-not to the ADC's AGND pad.

Does the AD677-EB require external calibration components?

No, the AD677-EB does not require external calibration components. It features fully integrated autocalibration using on-chip microcode, RAM, and a calibration DAC to measure and correct capacitor mismatch and offset errors. The AD677-EB stores correction coefficients internally and applies them automatically during normal conversion-eliminating trim pots, external DACs, or calibration routines in host firmware. Calibration is initiated solely by the CAL pin.

What is the minimum and maximum clock frequency supported by the AD677-EB?

While the AD677-EB accepts variable CLK frequencies, optimal accuracy is achieved with a CLK period of 580 ns (≈1.72 MHz), as specified for stable performance over temperature. The absolute timing limits define a minimum CLK period of 480 ns (max 2.08 MHz) and a maximum conversion period of 1000 µs. Slower clocks are permitted but may degrade performance due to internal sample/hold droop; the device always requires exactly 17 CLK pulses per conversion regardless of frequency.

Can the AD677-EB operate with a 5 V reference instead of 10 V?

Yes, the AD677-EB supports VREF from 5 V to 10 V. At 5 V reference, the input range becomes ±5 V, power consumption drops to 360 mW (vs. 450 mW at 10 V), and typical INL remains ±1 LSB-but dynamic performance (e.g., S/(N+D)) degrades slightly (89 dB vs. 92 dB). The AD677-EB's specifications are explicitly characterized at both 5 V and 10 V references, and all timing and logic thresholds remain unchanged.

Is the AD677-EB pin-compatible with the AD676?

No, the AD677-EB is not pin-compatible with the AD676. The AD676 is a parallel-output variant offered in 28-pin DIP packages (ceramic or plastic), whereas the AD677-EB is a serial-output device in a 16-pin DIP. Their pin counts, signal assignments (e.g., AD676 has 16 data lines, BUSY, RD, CS), and power pin configurations differ fundamentally. Interchange requires PCB redesign and firmware changes to handle serial vs. parallel data transfer.