AD7225KNZ

Overview

The AD7225KNZ is a monolithic CMOS quad 8-bit digital-to-analog converter (DAC) featuring integrated output buffer amplifiers. It operates with supply voltages of VDD from 11.4 V to 16.5 V and VSS at -5 V, or as a single 15 V supply. The device provides four independent channels with separate reference inputs for each DAC, allowing flexible unipolar or bipolar output configurations. Key electrical specifications include a settling time of 4 µs maximum, differential nonlinearity of ±1 LSB, and integral nonlinearity of ±1 LSB. The component utilizes a double-buffered parallel interface compatible with TTL and CMOS logic levels.

Feature Summary

• Quad 8-bit voltage output DACs with integrated unity-gain buffer amplifiers
• Separate reference input terminals for each channel (VREFA through VREFD)
• Double-buffered parallel interface enabling simultaneous update of all four outputs via LDAC
• Operates with dual supplies (VDD: 11.4–16.5 V, VSS: -5 V) or single 15 V supply

Applications

• Programmable transversal filters requiring multiple synchronized analog taps
• Digital word multiplication systems utilizing simultaneous multi-channel updates
• Microprocessor-controlled data acquisition systems requiring isolated reference inputs

Procurement Notes

Verify the specific suffix 'KNZ' corresponds to the skinny 24-lead PDIP package variant when sourcing replacements. Confirm that the required operating temperature range aligns with the K version specification (-40°C to +85°C). Ensure that the system design accommodates the external reference voltage requirements, as the device does not contain internal references. Check pin compatibility if substituting with other packages in the AD7225 family.

Selection Notes

Select this component when four independent 8-bit DACs with simultaneous update capability are required on a single chip. The separate reference inputs allow for different voltage ranges per channel, unlike devices sharing a common reference. Choose the PDIP package for through-hole mounting applications. Ensure the application can provide the necessary VDD and VSS supply rails or a single 15 V rail with appropriate grounding strategies for optimal performance.

Part Context

The AD7225 belongs to the Analog Devices LC2MOS family of high-speed linear-compatible CMOS data converters. This technology integrates precision analog circuitry with high-speed digital logic on a single die. The AD7225 specifically addresses applications needing multiple low-resolution DACs with independent control, distinguishing it from higher-resolution single-channel devices or multiplexed DAC arrays.

Replacement Considerations

The AD7226 is a functional substitute offering 12-bit resolution in a 20-pin DIP package. Note that the pinout and resolution differ significantly from the AD7225. Other variants such as the AD7225LPZ offer the same functionality in a 28-lead PLCC surface-mount package. Verify interface timing and power supply requirements when cross-referencing these alternatives.