LMF40CIWM-100

Overview

The LMF40CIWM-100 is a dual high-performance switched capacitor filter manufactured by National Semiconductor. It integrates two independent universal filters within a single monolithic integrated circuit, designed for precision analog signal processing applications. The device utilizes switched capacitor technology to implement various filter functions without requiring external passive components such as resistors or capacitors. This integration reduces board space and improves reliability compared to discrete solutions.

Feature Summary

• Dual independent filter sections on a single chip
• Universal architecture supporting multiple filter responses
• Switched capacitor operation eliminates external passive components
• High performance with low distortion characteristics

Applications

• Telecommunications channel filtering
• Instrumentation signal conditioning
• Audio processing circuits
• Data acquisition systems

Procurement Notes

Verify the exact manufacturer origin as National Semiconductor was acquired by Texas Instruments. Confirm that the -100 suffix denotes specific factory testing or binning criteria rather than a functional deviation from the standard LMF40CIWM specification. Ensure compatibility with existing PCB footprints when sourcing replacements.

Selection Notes

Select this component when dual-channel filtering is required in a compact form factor. The switched capacitor design allows frequency tuning via an external clock, offering flexibility over fixed RC filters. Evaluate the clock feedthrough and harmonic rejection specifications against system noise requirements before finalizing the design.

Part Context

This part belongs to the LMF100/LMF40 family of universal switched capacitor filters. These devices were widely used in analog front-end designs prior to the dominance of digital signal processing. The LMF40 variant specifically offers two filter sections, providing cost and space advantages over using two separate single-filter ICs.

Replacement Considerations

• LMF40CIWM/NOPB
• LMF100CIWM