Analog Devices Inc. AD7657BSTZ-REEL

Overview

AD7657BSTZ-REEL from Analog Devices is a 14-bit, 6-channel simultaneous-sampling SAR ADC with true bipolar ±10 V/±5 V input ranges, 250 kSPS throughput, 82.5 dB SNR at 50 kHz, and integrated 2.5 V reference - designed for high-accuracy power line monitoring and multi-axis industrial control systems.

For engineers reviewing the AD7657BSTZ-REEL datasheet, AD7657BSTZ-REEL pinout, AD7657BSTZ-REEL application, or AD7657BSTZ-REEL equivalent, key selection criteria include simultaneous sampling capability across six independent channels, iCMOS-based ±16.5 V analog supply tolerance, parallel/serial/daisy-chain interface flexibility, and 4 ns aperture delay matching for phase-coherent acquisition.

Technical Context

The AD7657BSTZ-REEL implements six independent 14-bit successive approximation register (SAR) ADCs on a single iCMOS die, enabling true simultaneous sampling via three dedicated CONVST pins (A/B/C) that trigger paired channels (V1/V2, V3/V4, V5/V6). Its track-and-hold supports up to 12 MHz input bandwidth with 35 ps typical aperture jitter.

It integrates on-chip reference buffers and a 2.5 V reference (±0.02% initial accuracy, 6 ppm/°C drift), supports pin- or software-selectable ±4×VREF (±10 V) and ±2×VREF (±5 V) input ranges, and operates with AVCC/DVCC = 4.75–5.25 V, VDD = 5–16.5 V, VSS = −5 to −16.5 V, and VDRIVE = 2.7–5.25 V.

Key Specifications

Pinout & Package

AD7657BSTZ-REEL is housed in a 64-lead LQFP (10 mm × 10 mm, 0.5 mm pitch) with separate analog/digital ground planes and dedicated decoupling pins for reference stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7657BSTZ-REEL, the AD7656BSTZ-REEL delivers 2.5-bit higher resolution for precision metrology, while the AD7658BSTZ-REEL reduces system cost and data handling complexity at the expense of 12 dB SNR - making the AD7657BSTZ-REEL the optimal balance for industrial control requiring verified 14-bit performance.

Availability

AD7657BSTZ-REEL is available at Aetrix Electronics and suitable for power line monitoring, industrial motor control, and multi-axis positioning systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for AD7657BSTZ-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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The AD7657BSTZ-REEL belongs to the AD7656/AD7657/AD7658 family - engineered specifically for high-channel-count, phase-coherent data acquisition in harsh industrial environments with wide supply tolerance and integrated reference stability.

FAQ

What is the maximum analog input frequency supported by the AD7657BSTZ-REEL?

The AD7657BSTZ-REEL supports a full-power bandwidth of 12 MHz (−3 dB) and 2 MHz (−0.1 dB), enabling accurate digitization of signals up to 100 kHz with minimal amplitude error. Its 35 ps typical aperture jitter ensures phase coherence for multi-channel FFT-based analysis, and the 12 MHz bandwidth accommodates anti-aliasing filter design with adequate roll-off margin before the Nyquist limit at 250 kSPS.

Does the AD7657BSTZ-REEL require an external reference voltage?

No, the AD7657BSTZ-REEL includes an internal 2.5 V reference with ±0.02% initial accuracy and 6 ppm/°C temperature coefficient, fully characterized across −40°C to +85°C. It can also accept an external reference (2.5 V or 3.0 V) via the REFIN/REFOUT pin, but doing so disables the internal reference. The integrated solution reduces component count and improves long-term stability versus discrete reference ICs.

How does the AD7657BSTZ-REEL achieve simultaneous sampling across six channels?

The AD7657BSTZ-REEL uses three dedicated CONVST inputs (A, B, C) to independently trigger conversion on three ADC pairs: CONVST A starts V1/V2, CONVST B starts V3/V4, and CONVST C starts V5/V6. Each pair shares a common track-and-hold amplifier, ensuring sub-nanosecond inter-channel skew. Aperture delay matching is specified at 4 ns max, guaranteeing phase alignment critical for vector measurements in power systems.

What are the power supply requirements for the AD7657BSTZ-REEL?

The AD7657BSTZ-REEL requires four independent supplies: AVCC and DVCC (4.75–5.25 V), VDRIVE (2.7–5.25 V), and analog bipolar rails VDD (+5 to +16.5 V) and VSS (−5 to −16.5 V). At 250 kSPS, total supply current is 26 mA (normal operational mode), dissipating 140 mW. The STBY pin enables full power-down to 80 µA, and partial power-down reduces consumption to 7 mA while retaining register state.

Can the AD7657BSTZ-REEL interface with a 3.3 V microcontroller?

Yes - the VDRIVE pin sets the logic interface voltage (2.7–5.25 V), allowing direct connection to 3.3 V or 5 V hosts. Digital inputs (CS, RD, WR, SCLK, CONVST) accept 0.3×VDRIVE to 0.7×VDRIVE thresholds, and outputs (DB0–DB15, BUSY, DOUT A/B/C) drive to VDRIVE − 0.2 V high and 0.2 V low. No level-shifting circuitry is needed when VDRIVE = 3.3 V, simplifying integration with modern low-voltage MCUs.