Analog Devices Inc. AD7655ACPZ

Overview

AD7655ACPZ from Analog Devices is a low-cost, 4-channel, 16-bit, simultaneous-sampling SAR analog-to-digital converter with dual track-and-hold amplifiers, 500 kSPS throughput in normal mode, 0 V to 5 V unipolar input range, and parallel/serial (SPI/QSPI/MICROWIRE/DSP-compatible) interface - used in multichannel industrial data acquisition and 3-phase power control systems.

For engineers reviewing the AD7655ACPZ datasheet, AD7655ACPZ pinout, AD7655ACPZ application, or AD7655ACPZ equivalent, key selection criteria include simultaneous dual-channel sampling capability, impulse-mode power scaling (2.6 mW at 10 kSPS), 48-lead LQFP/LFCSP package compatibility, and true 16-bit resolution without pipeline delay.

Technical Context

The AD7655ACPZ implements a charge redistribution SAR architecture with two independent track-and-hold circuits enabling true simultaneous sampling across four analog inputs via internal multiplexing (INA1/INB1 or INA2/INB2 selected by A0). It integrates internal error correction, a conversion clock, and supports both parallel and 2-wire serial interfaces compatible with 3 V or 5 V logic levels.

Its functional block includes dual analog front-ends with channel-to-channel isolation of −92 dB at 100 kHz, aperture delay matching of 30 ps, and a −3 dB input bandwidth of 10 MHz. Operation is specified over −40°C to +85°C using single 5 V AVDD/DVDD and OVDD from 2.7 V to 5.25 V.

Key Specifications

Pinout & Package

AD7655ACPZ is available in a 48-lead LQFP (Lead Quad Flat Package) and 48-lead LFCSP (Lead Frame Chip Scale Package); both share identical pin numbering and function mapping per Analog Devices Rev. E datasheet. The exposed pad (EPAD) is internally connected to ground but not required for specified performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel, simultaneous-sampling ADC applications.

Compared with AD7654ACPZ, AD7655ACPZ adds integrated 4-channel multiplexing and A0-selectable dual-pair sampling without layout change; versus AD7656ASTZ, it trades channel count for higher throughput and smaller package - making AD7655ACPZ optimal for space-constrained 4-channel, high-speed industrial control.

Availability

AD7655ACPZ is available at Aetrix Electronics and suitable for AC motor control, 3-phase power monitoring, and industrial data acquisition requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD7655ACPZ 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.

The AD7655ACPZ belongs to the PulSAR® family of precision SAR ADCs designed specifically for industrial automation, energy metering, and motor control applications demanding simultaneous sampling, low power, and robust serial/parallel interfacing.

FAQ

What is the maximum sampling rate of the AD7655ACPZ in normal mode?

The AD7655ACPZ achieves a maximum throughput rate of 500 kSPS in normal mode, corresponding to a complete dual-channel conversion cycle every 2 µs. This specification is guaranteed over the full operating temperature range (−40°C to +85°C) with AVDD = DVDD = 5 V and VREF = 2.5 V, as confirmed in Table 2 of the Rev. E datasheet.

Does the AD7655ACPZ support true differential input configurations?

The AD7655ACPZ does not implement fully differential input stages; it accepts pseudo-differential inputs via INx/INxN pairs (e.g., INA1/INAN), where INxN serves as a dedicated ground sense. Its analog input structure is optimized for unipolar 0 V to 5 V operation with common-mode rejection of 55 dB at 100 kHz, as specified in the "Analog Input CMRR" parameter.

How does impulse mode affect power consumption in the AD7655ACPZ?

In impulse mode (IMPULSE = HIGH), the AD7655ACPZ scales power dissipation proportionally with throughput: 114–125 mW at 444 kSPS, 120 mW at 500 kSPS, and just 2.6 mW at 10 kSPS. This dynamic scaling is implemented via internal clock gating and reduced bias current, enabling ultra-low-power operation without sacrificing 16-bit resolution or linearity.

Can the AD7655ACPZ be used with a 3 V digital interface?

Yes - the AD7655ACPZ supports 3 V logic levels via its OVDD supply pin (2.7 V to 5.25 V), which independently powers the digital I/O interface. When OVDD = 3 V, all digital outputs (D[0:15], BUSY, EOC, etc.) swing between 0 V and 3 V, and inputs (RD, CS, A0, etc.) recognize 0.8 V VIH threshold, ensuring reliable interoperability with 3 V microcontrollers and FPGAs.

What is the purpose of the A0 pin on the AD7655ACPZ?

The A0 pin on the AD7655ACPZ selects which pair of analog inputs is simultaneously sampled: when A0 = LOW, INA1/INB1 are acquired; when A0 = HIGH, INA2/INB2 are acquired. This multiplexer control enables flexible channel grouping without external switching components, and is essential for applications like dual 3-phase monitoring or redundant sensor sampling in safety-critical systems.