Analog Devices Inc. AD7658BSTZ

Overview

AD7658BSTZ from Analog Devices is a 12-bit, 6-channel, simultaneous-sampling SAR ADC with true bipolar ±4×VREF (±10 V) and ±2×VREF (±5 V) input ranges, 250 kSPS throughput, and integrated 2.5 V reference. It delivers 73 dB SINAD at 50 kHz and operates across −40°C to +85°C in a 64-lead LQFP package for power line monitoring and multi-axis control systems.

For engineers reviewing the AD7658BSTZ datasheet, AD7658BSTZ pinout, AD7658BSTZ application, or AD7658BSTZ equivalent, this page provides verified specifications, validated pin functions, confirmed interface modes (parallel/serial/daisy-chain), real-world use cases, and two technically documented alternative parts for 12-bit simultaneous-sampling ADC selection.

Technical Context

The AD7658BSTZ implements six independent 12-bit successive approximation register (SAR) ADCs on a single iCMOS die, enabling true simultaneous sampling of all six channels via three dedicated CONVST pins (A/B/C). Its track-and-hold amplifiers support 12 MHz full-power bandwidth and achieve 4 ns aperture delay matching between channels.

It integrates an on-chip 2.5 V reference with 6 ppm/°C temperature coefficient and supports flexible digital interfacing: high-speed parallel bus (with RD/WR/CS), SPI-/QSPI-/MICROWIRE-/DSP-compatible serial mode, and daisy-chain capability for multi-ADC systems without additional logic.

Key Specifications

Pinout & Package

AD7658BSTZ is housed in a 64-lead LQFP (10 mm × 10 mm, 0.5 mm pitch) with exposed thermal pad. The package supports standard reflow soldering (Pb-free: 260°C peak).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit simultaneous-sampling ADC applications.

Compared with AD7657ASTZ, the AD7658BSTZ trades 2 bits of resolution and ~8 dB SINAD for lower cost and reduced processing overhead; versus ADS8588HIPM, it offers 2.5× higher throughput and parallel interface flexibility at the expense of absolute precision and package size.

Availability

AD7658BSTZ is available at Aetrix Electronics and suitable for power line monitoring, multi-axis positioning systems, and industrial PLC analog input modules requiring stable component supply, long-lifecycle assurance, and traceable sourcing.

Supply support for AD7658BSTZ 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 AD765x family-including AD7658BSTZ-is designed for industrial data acquisition where simultaneous sampling, bipolar input handling, and integrated reference reduce system complexity in power quality, motion control, and test equipment.

FAQ

What is the maximum analog input voltage range supported by the AD7658BSTZ?

The AD7658BSTZ supports two hardware-selectable bipolar input ranges: ±4 × VREF (±10 V when using the internal 2.5 V reference) and ±2 × VREF (±5 V). These ranges are configured via the RANGE pin or software control bits RNGA–RNGC. Input voltage must remain within VSS − 0.3 V to VDD + 0.3 V per Absolute Maximum Ratings, with VDD/VSS supplies set accordingly (e.g., ±15 V for ±10 V full-scale operation). The AD7658BSTZ does not support unipolar or offset-binary coding modes.

Does the AD7658BSTZ require an external reference, or can it operate with its internal reference?

The AD7658BSTZ can operate autonomously using its integrated 2.5 V reference, which is enabled by default and buffered at the REFIN/REFOUT pin. External reference is optional and only needed when higher initial accuracy (<±0.1%) or lower temperature drift (<6 ppm/°C) is required. When using the internal reference, decoupling capacitors (10 µF + 100 nF) must be connected to REFCAPA/B/C pins per the AD7658BSTZ datasheet Layout Guidelines.

How does the AD7658BSTZ achieve simultaneous sampling across all six channels?

The AD7658BSTZ achieves true simultaneous sampling using three independent CONVST inputs (CONVST A, B, C), each controlling a pair of ADCs: CONVST A triggers V1/V2, CONVST B triggers V3/V4, and CONVST C triggers V5/V6. All six track-and-hold circuits switch from track to hold within 4 ns of each other, ensuring sub-degree phase alignment at 50 Hz. This architecture avoids time-skew errors inherent in multiplexed converters and is validated in the AD7658BSTZ Timing Specifications table (t_ACQ, aperture delay matching).

What digital interface options does the AD7658BSTZ support, and are they mutually exclusive?

The AD7658BSTZ supports parallel, serial, and daisy-chain interface modes selected via the SER/PAR pin. Parallel mode uses DB0–DB15, RD, WR, CS, and BUSY for maximum throughput (250 kSPS). Serial mode uses SCLK, CS, and SDATA (DOUT A/B/C multiplexed) and is SPI-/QSPI-/MICROWIRE-/DSP-compatible. Daisy-chain mode allows cascading multiple AD7658BSTZ devices on one serial bus. These modes are mutually exclusive-only one may be active per configuration-but SER/PAR can be changed dynamically in software.

What is the power consumption of the AD7658BSTZ in normal operational mode, and how is it distributed across supplies?

In normal operational mode at 250 kSPS, the AD7658BSTZ draws ≤26 mA total supply current: ≤0.25 mA from VSS, ≤0.25 mA from VDD, ≤26 mA from AVCC/DVCC/VDRIVE (all at 5.25 V). Total power dissipation is 140 mW, comprising ~75 mW in analog circuitry (AVCC/VDD/VSS), ~55 mW in digital core (DVCC), and ~10 mW in interface drivers (VDRIVE). Full power-down (STBY high) reduces current to ≤80 µA, consuming just 100 µW.