AD7112CR

Overview

The AD7112CR is a dual 17-bit R-2R CMOS multiplying digital-to-analog converter (DAC) housed in a 20-pin SOIC package. It provides two independent current outputs with a resolution of 0.375 dB per step, supporting an attenuation range up to 88.5 dB. The device operates on a single +5 V supply and accepts 8-bit parallel data via standard logic inputs. Key specifications include a maximum gain error of ±0.15 dB and output leakage currents of ±400 nA max across the industrial temperature range of –40 °C to +85 °C.

Feature Summary

• Dual 17-bit R-2R CMOS architecture for high-resolution signal attenuation
• 0.375 dB resolution with monotonic operation over specified ranges
• Multiplying capability allowing variable gain control based on reference input
• Integrated internal feedback resistors (9.3 kΩ/15.7 kΩ) simplifying circuit design

Applications

• Automatic Gain Control (AGC) systems requiring precise attenuation adjustment
• Programmable state variable filters for controlling resonant frequency and Q factor
• Audio processing circuits utilizing digital volume control or equalization

Procurement Notes

Verify that the component is sourced from authorized distributors to ensure authenticity. Confirm the package type matches the required 20-pin SOIC (R-20) form factor. Check for ESD sensitivity during handling and storage, as the device contains electrostatic discharge sensitive circuitry. Ensure the operating voltage remains within the specified 4.75 V to 5.25 V range for guaranteed performance.

Selection Notes

Select the C version when an accuracy of ≤ ±0.35 dB for 0.75 dB steps is sufficient, covering up to 42 dB of attenuation. Choose the B version if tighter accuracy (≤ ±0.17 dB for 0.375 dB steps) is required. Ensure the external operational amplifier has low input bias current (<10 nA) and low offset voltage (<50 µV) to minimize DC errors at the output. Consider adding a compensation capacitor (5–15 pF) in the feedback path when using high-speed amplifiers to prevent phase lag issues.

Part Context

The AD7112CR belongs to the AD7112 family of dual multiplying DACs produced by Analog Devices Inc. It is designed for applications requiring precise digital control of analog signal levels. The 'CR' suffix indicates the C grade accuracy level and the SOIC-20 plastic surface-mount package. This component serves as a core element in programmable attenuators and variable gain amplifiers where digital interfaces are preferred over mechanical potentiometers.

Replacement Considerations

Public confirmed substitute part numbers: None.