AD7111KNZ

Overview

The AD7111KNZ is a monolithic logarithmic multiplying digital-to-analog converter (DAC) from Analog Devices, part of the LOGDAC family. It provides an attenuation range of 0 dB to 88.5 dB with a nominal resolution of 0.375 dB per step. The device utilizes an onboard 8-bit buffer and decode logic to drive a 17-bit R-2R ladder. Operating on a single +5 V supply, it features unbuffered current output and accepts standard parallel digital inputs. 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

• Provides 88.5 dB dynamic range with 0.375 dB resolution steps
• Integrates 17-bit R-2R DAC with 8-bit input decode logic
• Operates on a single +5 V power supply
• Features transparent latch operation for AD7111A variants

Applications

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

Procurement Notes

Verify the specific grade suffix against the ordering guide. The 'K' designation indicates a commercial temperature range (0°C to +70°C). Confirm that the 'N' suffix corresponds to the 16-pin Plastic DIP package. Ensure the datasheet revision matches the design requirements, as specifications may vary between AD7111 and AD7111A grades.

Selection Notes

Select this component when high-resolution logarithmic attenuation is required. The AD7111 uses edge-triggered write signals, whereas the pin-compatible AD7111A supports level-triggered transparent latching. Designers must account for the varying equivalent output impedance of the DAC and select an output amplifier with low bias current and offset voltage to maintain accuracy across the full attenuation range.

Part Context

The AD7111KNZ belongs to the LOGDAC series, which combines precision bipolar circuits with CMOS logic using LC2MOS technology. This family allows for wide dynamic range attenuation in compact packages. The K-grade variant is specified for commercial applications, offering guaranteed monotonicity and accuracy within defined attenuation ranges compared to industrial or military grades.

Replacement Considerations

The AD7111A is pin-compatible with the industry-standard AD7524, allowing for upgrades to existing designs requiring wider dynamic range.