AD7862ARSZ-2REEL

Overview

The AD7862ARSZ-2REEL is a dual 12-bit successive approximation analog-to-digital converter (ADC) from Analog Devices, designed for simultaneous sampling applications. It operates on a single +5 V supply and features two independent ADC cores with four analog input channels grouped into two selectable channels via the A0 pin. The device supports an input voltage range of 0 V to +2.5 V, includes an internal +2.5 V reference, and provides overvoltage protection up to +7 V. Key electrical parameters include a maximum conversion time of 3.6 μs, a throughput rate of 250 kSPS, and a typical power dissipation of 60 mW in normal mode. It utilizes a high-speed parallel interface for data output.

Feature Summary

• Simultaneous sampling and conversion of two channels preserves relative phase information between signals.
• Integrated track/hold amplifiers ensure accurate acquisition of full-scale sine waves at maximum throughput rates.
• Automatic power-down mode reduces power consumption significantly after each conversion cycle completes.
• High-speed parallel interface allows direct connection to microprocessors and digital signal processors.

Applications

• AC motor control systems requiring precise phase tracking
• Uninterrupted power supplies (UPS) monitoring
• Data acquisition systems needing multi-channel synchronization

Procurement Notes

Verify that the specific suffix 'REEL' indicates tape-and-reel packaging rather than tube packaging when reviewing distributor listings. Confirm the '-2' designation corresponds to the 0 V to +2.5 V unipolar input range variant. Ensure the component meets the required industrial or extended temperature specifications based on the base model code.

Selection Notes

Select this variant specifically for applications requiring a unipolar 0 V to +2.5 V input range. Choose the AD7862-10 or AD7862-3 versions if bipolar ±10 V or ±2.5 V inputs are necessary. Consider the AD7863 if a 14-bit resolution upgrade is needed while maintaining pin compatibility. Evaluate the need for external references if tighter tolerance than the internal 2.5 V source is required.

Part Context

This component belongs to the AD7862 family of dual 12-bit ADCs manufactured by Analog Devices. It shares architectural similarities with the AD7863 but offers lower resolution. The device is fabricated using Linear Compatible CMOS (LC2MOS) process technology, combining precision bipolar circuits with low-power CMOS logic for optimal performance in mixed-signal environments.

Replacement Considerations

The AD7863 serves as a 14-bit pin-compatible upgrade option within the same family. Other variants such as AD7862AR-10 or AD7862BR-3 may be considered if different input ranges or package types are acceptable for the design.

FAQ

How does the A0 pin affect data reading?

The A0 pin selects the multiplexer channel. When A0 is low, reads access Channel A inputs (VA1, VA2); when A0 is high, reads access Channel B inputs (VB1, VB2).

What is the purpose of the BUSY signal?

The BUSY signal goes high upon the falling edge of CONVST and remains high until the conversion is complete, indicating when the data outputs are valid for reading.

Can the internal reference be used externally?

Yes, the internal +2.5 V reference can be accessed via the VREF pin, but it should be buffered externally because the output impedance is nominally 2 kΩ due to an internal FET switch.