AD7224LR-18

Overview

The AD7224LR-18 is an 8-bit voltage-output digital-to-analog converter (DAC) with integrated output amplifiers, fabricated in Analog Devices' LC2MOS process. It features a double-buffered interface for simultaneous updates in multi-DAC systems and operates with single or dual supplies. The device guarantees a total unadjusted error of ±1 LSB maximum over the –40°C to +85°C temperature range. Key electrical parameters include a reference input voltage range of +2 V to +12.5 V, a typical power consumption of 35 mW with a single supply, and a settling time of 5 μs to ±1/2 LSB for positive full-scale changes. The output amplifier can drive loads down to 2 kΩ.

Feature Summary

• Integrated 8-bit DAC and unity-gain output amplifier on a monolithic CMOS chip
• Double-buffered interface logic allows simultaneous update of multiple devices
• Low total unadjusted error of ±1 LSB max over the industrial temperature range
• Compatible with TTL and 5 V CMOS logic levels

Applications

• Microprocessor-based control systems requiring simultaneous multi-channel updates
• Battery-powered instrumentation utilizing single-supply operation
• System calibration cycles using the zero override function via the RESET line

Procurement Notes

Verify the specific suffix LR-18 corresponds to the R-18 package option (18-Lead SOIC) and the K/L version temperature range (–40°C to +85°C). Confirm that the required total unadjusted error specification aligns with the ±1 LSB maximum rating provided for this variant. Ensure ESD precautions are observed during handling as the device is electrostatic sensitive.

Selection Notes

Select the AD7224LR-18 when a low-power, high-reliability 8-bit DAC with built-in buffering is required. The double-buffered architecture is essential for applications needing synchronized output updates across multiple channels. Verify that the system's microprocessor interface timing meets the minimum pulse width requirements of 90 ns for CS/WR signals. Consider the single-supply capability if negative rails are unavailable, noting potential impacts on sink current near ground.

Part Context

The AD7224 series utilizes Linear Compatible CMOS (LC2MOS) technology to integrate precision analog circuits with high-speed digital logic. This fabrication method enables low power consumption and improved reliability compared to multi-chip solutions. The LR-18 designation identifies the specific package and temperature grade within the broader AD7224 family, which includes variants with different accuracy grades and package options such as DIP and PLCC.

Replacement Considerations

Direct pin-compatible replacements within the same accuracy grade and package require checking the ordering guide for other suffixes like AD7224LP or AD7224KR-18. Note that while these share the same footprint, verify if the alternative part number offers the same ±1 LSB total unadjusted error specification.