AD7111KN

Overview

The AD7111KN is a monolithic logarithmic multiplying digital-to-analog converter (DAC) from the LOGDAC family, manufactured by Analog Devices Inc. It provides an attenuation range of 0 dB to 88.5 dB with a nominal resolution of 0.375 dB. The device utilizes an onboard 8-bit buffer and decode logic to translate input data into a 17-bit word for a 17-bit R-2R ladder. Operating on a single +5 V supply, it features current output and accepts parallel digital inputs via standard microprocessor control lines. The component is housed in a 16-pin plastic DIP package and operates within a commercial temperature range of 0°C to +70°C.

Feature Summary

• Logarithmic Attenuation: Provides 0 dB to 88.5 dB dynamic range in 0.375 dB steps using internal decode logic.
• High Resolution Architecture: Employs a 17-bit R-2R ladder driven by an 8-bit digital input word.
• Single Supply Operation: Functions with a +5 V power supply and low power consumption.
• Microprocessor Interface: Compatible with standard 8-bit MPU buses using edge-triggered Write (WR) and Chip Select (CS) signals.

Applications

• Audio Attenuators
• Sonar Systems
• Function Generators
• Digitally Controlled AGC Systems

Procurement Notes

Verify component authenticity through authorized distributors or direct manufacturer channels. Confirm the specific grade matches design requirements, as accuracy and monotonic ranges vary between K/B/T grades and other variants. Ensure proper ESD handling procedures are followed during installation due to the sensitivity of the CMOS circuitry.

Selection Notes

Select the AD7111KN when a logarithmic response is required rather than linear conversion. Verify that the guaranteed monotonic range at 0.375 dB steps (0 dB to 60 dB for this grade) meets system specifications. Consider the propagation delay and refresh time constraints if interfacing with high-speed microprocessors. Ensure the output amplifier selection supports the required bandwidth and offset voltage characteristics.

Part Context

The AD7111KN belongs to the AD7111/AD7111A LOGDAC series, which integrates decoding logic to simplify interface requirements. While the AD7111A is pin-compatible with the industry-standard AD7524, the AD7111 variant offers enhanced dynamic range and finer resolution. This part represents the commercial grade version designed for general-purpose applications requiring precise logarithmic signal control.

Replacement Considerations

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