Analog Devices Inc. AD677JRZ-REEL

Overview

AD677JRZ-REEL from Analog Devices is a 16-bit, 100 kSPS autocalibrating successive-approximation ADC with on-chip sample-hold, serial output, and ±VREF input range (±5 V to ±10 V). It employs switched-capacitor charge redistribution architecture, delivers 92 dB S/(N+D), –99 dB THD, and 1 MHz full-power bandwidth, and is used in precision instrumentation and data acquisition systems requiring high dc accuracy and dynamic performance.

For engineers reviewing the AD677JRZ-REEL datasheet, AD677JRZ-REEL pinout, AD677JRZ-REEL application, or AD677JRZ-REEL equivalent, key selection considerations include its 16-pin SOIC package, dual ±12 V / +5 V supply requirement, autocalibration timing (85,532 clock cycles), bipolar zero error (±2 LSB), and serial two's complement output synchronized to SCLK.

Technical Context

The AD677JRZ-REEL integrates two monolithic chips-an analog BiMOS II ADC die and a digital DSP CMOS controller-within a single SOIC package. Its SAR architecture uses binary-weighted capacitor arrays instead of resistor ladders, eliminating temperature-induced linearity drift and enabling inherent sample-hold functionality without external components.

Autocalibration is performed via an on-chip microcoded controller that measures capacitor mismatch errors using a calibration DAC, stores correction values in RAM, and applies them during conversion. The device requires 17 CLK pulses per conversion, outputs MSB-first two's complement data on SDATA synchronized to SCLK, and supports continuous conversion mode with precise timing control via SAMPLE and BUSY signals.

Key Specifications

Pinout & Package

AD677JRZ-REEL is housed in a 28-lead plastic SOIC (R-28) package with gull-wing leads, 1.27 mm pitch, and JEDEC MS-012AC compliant footprint. Pin 1 is marked by a beveled corner or dot; thermal pad is not present.

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 AD677JRZ-REEL provides superior dc accuracy (±1.5 LSB INL vs ±2.5 LSB) and lower THD (–99 dB vs –92 dB), but requires three supplies and discrete reference management-making it optimal for static-accuracy-critical, single-channel industrial measurement rather than multi-channel or portable use.

Availability

AD677JRZ-REEL is available at Aetrix Electronics and suitable for high-precision instrumentation, industrial process monitoring, and test & measurement equipment requiring stable component supply, long-term lifecycle support, and guaranteed parametric compliance over 0°C to +70°C.

Supply support for AD677JRZ-REEL 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, with design centers worldwide and ISO 9001-certified manufacturing.

The AD677JRZ-REEL belongs to Analog Devices' legacy precision SAR ADC product line, engineered specifically for applications demanding uncompromised dc accuracy, low distortion, and self-calibrating operation in laboratory, industrial, and medical instrumentation.

FAQ

What is the maximum recommended conversion rate for the AD677JRZ-REEL?

The AD677JRZ-REEL is specified for a maximum conversion rate of 100 kSPS, corresponding to a minimum conversion period of 10 µs. This rate is achieved using exactly 17 CLK pulses per conversion. Exceeding this rate degrades performance due to internal sample-hold droop and timing margin violations, as confirmed in the Timing Specifications table (tC = 10 µs min).

Does the AD677JRZ-REEL require an external voltage reference?

Yes, the AD677JRZ-REEL requires an external precision voltage reference applied to the VREF pin. It accepts 5 V to 10 V inputs, and its full-scale range is ±VREF. No internal reference is provided; reference stability and noise directly impact INL, THD, and S/(N+D) performance per Figure 11 and the DC/AC specifications tables.

How does autocalibration work in the AD677JRZ-REEL, and how often must it be performed?

Autocalibration in the AD677JRZ-REEL uses an on-chip microcontroller and calibration DAC to measure and correct capacitor mismatch and offset errors, storing correction values in RAM. It is typically performed once at power-up after supplies and VREF stabilize. If skipped, performance may degrade to ~10-bit level. Calibration takes 85,532 CLK cycles (~86 ms at 1 MHz CLK) and is triggered by pulsing CAL HIGH then LOW.

What are the critical PCB layout requirements for the AD677JRZ-REEL?

Critical layout requirements for the AD677JRZ-REEL include: (1) separate AGND and DGND planes tied at a single point near the IC, (2) 0.1 µF ceramic decoupling capacitors placed <2 mm from each supply pin (VCC, VEE, VDD), (3) AGND SENSE routed as a dedicated low-impedance trace to the signal source ground, and (4) VIN and VREF traces shielded from digital switching noise per Figure 4 grounding recommendations.

Can the AD677JRZ-REEL operate with a single +5 V supply?

No, the AD677JRZ-REEL cannot operate with a single +5 V supply. It requires three independent supplies: +12 V (VCC), –12 V (VEE), and +5 V (VDD). Attempting operation with only +5 V will prevent proper analog circuit biasing, disable the comparator and DAC, and result in non-functional conversion-per Absolute Maximum Ratings and Power Supplies section.