Analog Devices Inc. AD7656A-1BSTZ-RL

Overview

AD7656A-1BSTZ-RL from Analog Devices is a 6-channel, simultaneous-sampling, 16-bit SAR ADC with true bipolar ±10 V/±5 V input ranges, 250 kSPS throughput, on-chip 2.5 V reference, and iCMOS process technology - deployed in power line monitoring, multiaxis positioning, and industrial instrumentation systems.

For engineers reviewing the AD7656A-1BSTZ-RL datasheet, AD7656A-1BSTZ-RL pinout, AD7656A-1BSTZ-RL application, or AD7656A-1BSTZ-RL equivalent, key selection considerations include simultaneous 6-channel sampling capability, ±4×VREF/±2×VREF hardware- or software-selectable input range, daisy-chain serial interface support, and built-in power supply sequencing robustness for high-voltage analog front-ends.

Technical Context

The AD7656A-1BSTZ-RL integrates six independent 16-bit successive approximation register (SAR) ADCs with track-and-hold amplifiers (4.5 MHz full-power bandwidth), controlled by three dedicated CONVST pins (A/B/C) enabling independent simultaneous sampling of three ADC pairs (V1/V2, V3/V4, V5/V6). It uses an internal oscillator and supports both parallel and high-speed serial interfaces (SPI/QSPI/MICROWIRE/DSP-compatible) with daisy-chain mode enabled via DCEN pin.

Its iCMOS process enables ±16.5 V analog supply operation (VDD/VSS) while maintaining 5 V digital logic compatibility (AVCC/DVCC/VDRIVE), and incorporates on-chip reference buffers with REFCAPA/B/C decoupling pins, REFEN/DIS control for internal/external reference selection, and hardware/software mode selection (H/S SEL) for flexible system integration.

Key Specifications

Pinout & Package

64-lead LQFP (10 mm × 10 mm, 0.5 mm pitch), RoHS-compliant, with separate AGND/DGND planes, dual analog supplies (VDD/VSS), and multifunction pins supporting parallel byte/word and serial daisy-chain modes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7656BSTZ-REEL, AD7656A-1BSTZ-RL delivers identical performance with lower component count and improved supply sequencing tolerance; versus LTC2358-18IUKG#PBF, it trades resolution and channel count for true bipolar input, faster throughput, and direct high-voltage analog interface - making it optimal for industrial power measurement where phase coherence and ruggedness are paramount.

Availability

AD7656A-1BSTZ-RL is available at Aetrix Electronics and suitable for power line monitoring, multiaxis positioning, and industrial instrumentation requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for AD7656A-1BSTZ-RL 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 AD7656A-1BSTZ-RL belongs to the iCMOS-based precision ADC product line, engineered specifically for high-voltage industrial data acquisition where simultaneous sampling, bipolar input integrity, and supply sequencing resilience are mandatory.

FAQ

What is the maximum analog input voltage range supported by the AD7656A-1BSTZ-RL?

The AD7656A-1BSTZ-RL supports two pin- or software-selectable input ranges: ±4 × VREF (±10 V with internal 2.5 V reference) and ±2 × VREF (±5 V). With VREF = 2.5 V, this corresponds to ±10 V or ±5 V full-scale ranges. The absolute input voltage must remain within VSS + 1 V to VDD − 1 V, where VDD/VSS can be set from ±6 V to ±16.5 V depending on selected range - ensuring compatibility with high-voltage industrial transducers.

Does the AD7656A-1BSTZ-RL require external decoupling capacitors on its reference pins?

Yes, the AD7656A-1BSTZ-RL requires external decoupling: a minimum 1 µF capacitor must be placed between REFIN/REFOUT and AGND, and individual 1 µF capacitors must connect REFCAPA, REFCAPB, and REFCAPC to AGND. These capacitors stabilize the on-chip reference buffers for each ADC pair and are essential to achieve specified SNR (88 dB) and reference drift (25 ppm/°C). Omitting them degrades noise performance and full-scale accuracy.

Can the AD7656A-1BSTZ-RL perform simultaneous sampling across all six channels?

Yes, the AD7656A-1BSTZ-RL supports true simultaneous sampling across all six channels using three dedicated CONVST inputs: CONVST A triggers V1/V2, CONVST B triggers V3/V4, and CONVST C triggers V5/V6. All six conversions begin at the exact same instant, with aperture delay matching of ≤4 ns - enabling coherent phase measurements in 3-phase power systems without post-processing interpolation.

What interface modes does the AD7656A-1BSTZ-RL support, and how is mode selection implemented?

The AD7656A-1BSTZ-RL supports high-speed parallel (16-bit word or 8-bit byte), serial SPI/QSPI/MICROWIRE, and daisy-chain modes. Mode selection is controlled by the SER/PAR SEL pin: logic low enables parallel interface; logic high enables serial interface. In serial mode, DB8–DB10 become DOUT A–DOUT C, and DCEN (pin 10) enables daisy-chain configuration - allowing up to 16 devices on a single SPI bus with minimal MCU resource usage.

Is the internal reference of the AD7656A-1BSTZ-RL factory-trimmed, and what is its long-term stability?

Yes, the AD7656A-1BSTZ-RL's internal 2.5 V reference is factory-trimmed to 2.49–2.51 V (±0.4%) with a temperature coefficient of 25 ppm/°C (max) and long-term stability of 150 ppm over 1000 hours. This specification is guaranteed across the full operating temperature range (−40°C to +85°C) and eliminates the need for external calibration in most industrial applications - reducing system cost and improving time-to-market for metering and control designs.