AD7899ARZ-3

Overview

The AD7899ARZ-3 is a 14-bit successive-approximation analog-to-digital converter (ADC) operating from a single 5 V supply. It delivers a maximum throughput rate of 400 kSPS with a conversion time of 2.2 µs and a track/hold acquisition time of 0.3 µs. The device features an internal 2.5 V reference, on-chip clock oscillator, and signal conditioning circuitry. It accepts bipolar input ranges of ±2.5 V and utilizes a high-speed parallel interface compatible with 3 V or 5 V processors. Typical power consumption is 80 mW in normal mode, reducing to 20 µW in standby.

Feature Summary

• Integrated overvoltage protection on analog inputs allows operation without damage when input voltages exceed specified ranges.
• Flexible clocking architecture supports both an internally trimmed laser-trimmed oscillator and external clock inputs for precise timing control.
• Dual-mode digital interface accommodates both 3 V and 5 V logic levels via the VDRIVE pin, facilitating direct connection to various microprocessors.

Applications

• Industrial process control systems requiring high-resolution data acquisition
• Portable instrumentation powered by single-supply batteries
• Data acquisition modules interfacing with 3 V or 5 V digital signal processors

Procurement Notes

Verify the specific suffix '-3' corresponds to the ±2.5 V input range variant before integration. Confirm that the SOIC-28 package thermal characteristics meet the system's dissipation requirements. Ensure the design accounts for the 0.1 µF decoupling capacitor required on the VREF pin to maintain reference stability during operation.

Selection Notes

Select this component when a single-channel, 14-bit resolution is required with a ±2.5 V input span. The AD7899ARZ-3 is suitable for applications needing fast conversion speeds up to 400 kSPS while maintaining low power consumption. Consider the parallel interface complexity versus serial alternatives if board space or pin count is constrained.

Part Context

The AD7899 series includes variants with different input ranges: AD7899-1 for ±10 V/±5 V, AD7899-2 for 0 V to 5 V/2.5 V, and AD7899-3 for ±2.5 V. All share the same 14-bit SAR architecture and 400 kSPS throughput capability. The ARZ designation indicates a lead-free, RoHS-compliant SOIC-28 package version within the Analog Devices portfolio.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.

FAQ

How is the conversion clock selected between internal and external sources?

The clock source is determined by the state of the CLKIN pin at the rising edge of CONVST. If CLKIN is high, an external clock is used; if low, the internal oscillator is engaged.

What is the function of the BUSY/EOC pin?

The BUSY/EOC pin signals the status of the conversion. It goes high when CONVST rises and remains high until the conversion completes, indicating either busy status or end-of-conversion depending on the CONVST state.

Can the internal reference be used externally?

Yes, the VREF pin provides access to the internal 2.5 V reference. However, it has a nominal output impedance of 6 kΩ, so buffering is recommended if driving external loads.