Analog Devices Inc. AD7986BCPZ

Overview

AD7986BCPZ from Analog Devices is an 18-bit, 2 MSPS successive approximation ADC with true differential input range of ±VREF, 95.5 dB SNR (internal reference), 15 mW power dissipation at 2 MSPS, and no pipeline delay - used in high-precision seismic data acquisition and medical instrumentation where low latency and high dynamic range are critical.

For engineers reviewing the AD7986BCPZ datasheet, AD7986BCPZ pinout, AD7986BCPZ application, or AD7986BCPZ equivalent, this page delivers verified specifications, validated daisy-chain interface behavior, confirmed LFCSP-20 package mapping, and real-world trade-offs between internal vs. external reference configurations.

Technical Context

The AD7986BCPZ implements a charge redistribution SAR architecture with dual 18-bit binary-weighted capacitor arrays, enabling zero-latency conversion and precise differential sampling on IN+ and IN−. It supports two operational modes: Turbo (2 MSPS, continuous conversion) and Normal (1.5 MSPS, inter-conversion power-down).

Its serial interface operates in CS mode (3-/4-wire SPI-compatible) or Chain mode (daisy-chainable with busy indicator), all compatible with 1.8 V/2.5 V/2.7 V logic via dedicated VIO supply. The internal 4.096 V reference exhibits ±10 ppm/°C drift and requires 10 µF decoupling at REF.

Key Specifications

Pinout & Package

AD7986BCPZ is housed in a 20-lead 4 mm × 4 mm LFCSP (Lead Frame Chip Scale Package) with exposed thermal pad (EPAD) recommended to be soldered to system ground plane for reliability and thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-resolution SAR ADC applications.

Compared with AD7985BCPZ, AD7986BCPZ delivers 2 additional bits of resolution and integrated reference flexibility at higher power; compared with AD7691BRMZ, it offers 8× higher throughput and LFCSP packaging but requires more careful power and layout design.

Availability

AD7986BCPZ is available at Aetrix Electronics and suitable for seismic data acquisition, portable medical instrumentation, high-accuracy data acquisition systems, and battery-powered test equipment requiring stable component supply, long-term lifecycle support, and guaranteed authenticity.

Supply support for AD7986BCPZ 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 Norwood, MA, with R&D and manufacturing facilities worldwide.

The AD7986BCPZ belongs to the PulSAR® family of precision SAR ADCs designed for applications demanding high resolution, low power, and zero-latency conversion - particularly in instrumentation, medical, and industrial sensing.

FAQ

What is the maximum sample rate of the AD7986BCPZ and how is it configured?

The AD7986BCPZ achieves a maximum sample rate of 2 MSPS in Turbo mode, enabled by driving the TURBO pin high. In Normal mode (TURBO = low), the throughput reduces to 1.5 MSPS to lower power consumption. Both modes are fully supported in the AD7986BCPZ datasheet Rev. D, with timing parameters explicitly defined for each configuration including tCONV (400 ns Turbo / 500 ns Normal) and tCYC (500 ns Turbo / 660 ns Normal).

Does the AD7986BCPZ require an external reference, or does it include an internal one?

The AD7986BCPZ includes a factory-trimmed 4.096 V internal reference with ±10 ppm/°C drift, activated by setting PDREF = low. When PDREF = high, the internal reference is disabled and an external reference (2.4 V to 5.1 V) must be applied to the REF pin. The AD7986BCPZ datasheet specifies distinct SNR (95.5 dB vs. 97.0 dB) and power (15 mW vs. 26 mW at 2 MSPS) for each configuration.

Can multiple AD7986BCPZ devices be connected on a single serial bus?

Yes, the AD7986BCPZ supports daisy-chain operation in Chain mode, selected by asserting SDI low at the CNV rising edge. In this mode, up to N devices share one SCK and SDO line, with each contributing its 18-bit result sequentially - the first device outputs its MSB after 18 SCK cycles, followed by the next, and so on. The AD7986BCPZ datasheet details timing constraints and busy indicator usage for reliable multi-device synchronization.

What package type and thermal considerations apply to the AD7986BCPZ?

The AD7986BCPZ uses a 20-lead 4 mm × 4 mm LFCSP with an exposed thermal pad (EPAD). Although unconnected internally, Analog Devices recommends soldering the EPAD to the PCB ground plane to improve thermal resistance (θJA = 30.4°C/W) and mechanical reliability. Layout guidelines in the AD7986BCPZ datasheet emphasize separate AGND/DGND/REFGND planes and localized decoupling for AVDD, DVDD, BVDD, and VIO.

How does the AD7986BCPZ handle analog input common-mode voltage?

The AD7986BCPZ specifies a common-mode input range of VREF × 0.475 to VREF × 0.525 - meaning for a 4.096 V reference, the common-mode voltage must be maintained between 1.946 V and 2.150 V. This tight window ensures optimal linearity and 100 dB CMRR at 500 kHz. The AD7986BCPZ datasheet Table 2 and Analog Inputs section confirm this range is fixed relative to VREF and not adjustable via external biasing.