Analog Devices Inc. AD7865BSZ-3

Overview

AD7865BSZ-3 from Analog Devices is a four-channel, simultaneous-sampling, 14-bit analog-to-digital converter (ADC) with ±2.5 V input range, 2.4 µs conversion time per channel, 0.35 µs track/hold acquisition time, and 77 dB SNR at 100 kHz input. It operates from a single 5 V supply and delivers 100 kSPS maximum throughput across all four channels for phase-critical motor control and power monitoring applications.

For engineers reviewing the AD7865BSZ-3 datasheet, AD7865BSZ-3 pinout, AD7865BSZ-3 application, or AD7865BSZ-3 equivalent, key selection criteria include simultaneous sampling integrity, aperture delay matching (≤4 ns), bipolar zero error match (≤6 LSB), internal 2.5 V reference accuracy (±20 mV), and compatibility with 3 V or 5 V digital interfaces via VDRIVE.

Technical Context

The AD7865BSZ-3 integrates four matched track/hold amplifiers and a successive approximation ADC core, enabling true simultaneous sampling to preserve inter-channel phase relationships in multi-signal acquisition. Its internal clock oscillator eliminates external timing components, while hardware/software channel selection (via SLx pins or DB0–DB3 register) supports flexible sequencing of subsets of the four inputs.

Conversion control uses CONVST to initiate hold and sequence start, BUSY to signal end-of-sequence, and EOC for per-channel completion. The 14-bit parallel interface supports both reading between conversions and post-sequence burst reads, with timing validated for 3 V and 5 V logic levels via dedicated VDRIVE supply.

Key Specifications

Pinout & Package

The AD7865BSZ-3 is housed in a 44-lead Plastic Quad Flatpack (PQFP) with 0.8 mm lead pitch and 10 mm × 10 mm body size. Pin 1 is marked by a corner notch; all AGND pins (12, 17, 23, 26) must be connected to system analog ground plane at a single point.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7865BSZ-3, AD7656ASTZ offers higher resolution and more channels but lacks native ±2.5 V support, while ADS8588SIPM provides configurable ranges and greater channel density but replaces the parallel interface with SPI - making AD7865BSZ-3 optimal for legacy 14-bit parallel bus designs requiring exact ±2.5 V full-scale compatibility.

Availability

AD7865BSZ-3 is available at Aetrix Electronics and suitable for AC motor control, uninterruptible power supplies, industrial power metering, and data acquisition systems requiring stable component supply and long-term production continuity.

Supply support for AD7865BSZ-3 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, founded in 1965 and headquartered in Wilmington, MA.

The AD7865 product line delivers precision simultaneous-sampling ADCs for real-time control and measurement systems where inter-channel timing integrity and DC accuracy are critical - especially in power electronics and industrial automation.

FAQ

What input voltage range does the AD7865BSZ-3 support?

The AD7865BSZ-3 supports a fixed ±2.5 V bipolar input range, optimized for signal processing applications. This differs from the AD7865-1 (±5 V/±10 V) and AD7865-2 (0 V to 2.5 V/0 V to 5 V) variants. Input overvoltage tolerance is –4 V to +18 V, protecting against transient excursions without affecting other channels' conversion integrity.

How does the AD7865BSZ-3 achieve simultaneous sampling across four channels?

The AD7865BSZ-3 achieves true simultaneous sampling using four independent, matched track/hold amplifiers - one per analog input pair (VIN1A/VIN1B through VIN4A/VIN4B). A single CONVST rising edge freezes all four inputs at identical instants, preserving phase relationships. Aperture delay matching is guaranteed ≤4 ns, ensuring sub-degree alignment at 100 kHz.

Can the AD7865BSZ-3 interface with 3 V microcontrollers?

Yes, the AD7865BSZ-3 supports 3 V digital interfacing via its dedicated VDRIVE pin, which powers the DB0–DB13 data bus, BUSY, EOC, and FRSTDATA outputs. When VDRIVE = 3 V ±10%, the outputs meet 3 V TTL logic thresholds (VOH ≥ 2.4 V, VOL ≤ 0.4 V), enabling direct connection to 3 V processors without level shifters.

What is the role of the H/S SEL pin on the AD7865BSZ-3?

The H/S SEL pin determines channel selection method: Logic 0 configures SL1–SL4 pins for hardware-based channel enable/disable (latched on CONVST rise); Logic 1 enables software control via DB0–DB3 register writes using CS/WR. This dual-mode flexibility allows fixed-sequence operation in resource-constrained systems or dynamic reconfiguration in programmable DAQ platforms.

Does the AD7865BSZ-3 include an internal voltage reference?

Yes, the AD7865BSZ-3 integrates a laser-trimmed 2.5 V reference with ±20 mV accuracy over temperature (–40°C to +85°C) and 25 ppm/°C temperature coefficient. The VREF pin provides access to this reference and accepts external 2.5 V ±5% sources for enhanced stability in metrology-grade applications.