AD7865BSZ-2

Overview

The AD7865BSZ-2 is a four-channel, simultaneous sampling, 14-bit successive approximation analog-to-digital converter (ADC) manufactured by Analog Devices. It operates from a single +5 V supply and features four track/hold amplifiers with an acquisition time of 0.35 µs and a conversion time of 2.4 µs per channel. The device supports unipolar input ranges of 0 V to 2.5 V or 0 V to 5 V. It includes an internal 2.5 V reference, on-chip clock oscillator, signal conditioning circuitry, and overvoltage protection on analog inputs up to ±18 V. The maximum throughput is 350 kSPS for a single channel and 100 kSPS for all four channels.

Feature Summary

• Four simultaneously sampled inputs preserve relative phase information across channels.
• Hardware or software selectable channel sequence allows conversion of any subset of the four channels.
• High-speed parallel interface facilitates connection to microprocessors and DSPs.
• Analog inputs feature overvoltage protection without damaging the device.

Applications

• AC Motor Control
• Uninterruptible Power Supplies
• Industrial Power Meters/Monitors
• Data Acquisition Systems

Procurement Notes

Verify the specific suffix '2' indicates the unipolar input range configuration (0 V to 2.5 V or 0 V to 5 V). Confirm the package type matches the required PCB layout, typically PQFP-44. Ensure the operating temperature range meets system requirements, as commercial versions support -40°C to +85°C. Cross-reference the datasheet revision to confirm pinout and electrical specifications remain consistent with current design standards.

Selection Notes

Select this component when simultaneous multi-channel sampling is required to maintain phase coherence. The AD7865BSZ-2 is appropriate for applications requiring unipolar voltage inputs within the specified ranges. Consider the power consumption of approximately 100 mW in normal mode against system thermal constraints. Evaluate the parallel interface complexity against available processor resources before finalizing the selection.

Part Context

The AD7865 series comprises three variants differentiated by analog input ranges: the AD7865-1 for bipolar ±10 V/±5 V, the AD7865-2 for unipolar 0 V to 2.5 V/0 V to 5 V, and the AD7865-3 for bipolar ±2.5 V. All variants share identical architecture, speed, and packaging. The BSZ designation indicates the B grade accuracy and plastic leaded quad flatpack package.

Replacement Considerations

Direct functional replacements include other ADI 14-bit simultaneous sampling ADCs such as the AD7865BSZ-1 or AD7865BSZ-3, provided the input voltage range matches the application requirements. Verify that substitute parts maintain the same 44-pin PQFP footprint and parallel interface timing characteristics.

FAQ

What is the difference between the AD7865-1, AD7865-2, and AD7865-3?

The primary difference is the analog input voltage range. The AD7865-1 supports ±10 V and ±5 V, the AD7865-2 supports 0 V to 2.5 V and 0 V to 5 V, and the AD7865-3 supports ±2.5 V.

How is the channel conversion sequence selected?

The sequence can be selected via hardware using the SL1-SL4 pins or via software by programming the channel select register through the DB0-DB3 data lines.

What is the maximum throughput rate for all four channels?

The maximum throughput rate for all four channels is 100 kSPS. For a single channel, the maximum throughput is 350 kSPS.