CD22204M

Overview

The CD22204M is a monolithic integrated circuit designed as a low-power subscriber Dual Tone Multiple Frequency (DTMF) receiver. Fabricated using complementary symmetry CMOS processing, it detects selectable groups of 12 or 16 standard DTMF digits without requiring front-end pre-filtering. The device operates on a single low-tolerance 5V supply and utilizes switched-capacitor filter technology to provide approximately 40 poles of filtering alongside digital circuitry on the same chip. It features three-state outputs for direct interfacing with standard CMOS circuitry and microprocessor-based systems.

Feature Summary

• Integrated switched-capacitor filter technology providing high-density analog and digital processing
• Eliminates need for external front-end band splitting filters
• Three-state outputs facilitate bus-oriented architectures
• Supports Alternate Time Base output to drive up to 10 additional receivers

Applications

• Telecom DTMF signaling circuits
• Subscriber line interface units
• Microprocessor-based telephone systems

Procurement Notes

Verify component authenticity through manufacturer documentation or authorized distributors. Confirm package type matches requirements, typically PDIP14. Check RoHS compliance status as original Harris/Intersil versions may not meet current environmental standards. Ensure voltage supply specifications align with system design constraints.

Selection Notes

Select this component when designing DTMF receivers requiring minimal external passive components. It is suitable for applications needing high system density and direct CMOS interfacing. Consider the requirement for an external 3.579545MHz crystal for frequency reference. Evaluate power consumption benefits against available alternatives in low-power telecom environments.

Part Context

The CD22204 series belongs to Intersil's (formerly Harris) telecommunications IC portfolio. It represents a specialized solution for DTMF detection in subscriber equipment. The 'M' suffix typically denotes a plastic dual in-line package variant, distinguishing it from ceramic packages like the CDIP version.

Replacement Considerations

Direct pin-to-pin replacements are limited due to specific switched-capacitor architecture. Verify compatibility with existing 3.579545MHz crystal references. Check if alternative DTMF receivers support similar three-state output configurations and ATB driving capabilities.