DTMF RECEIVER
High-Performance Silicon-Gate CMOS

The IN9270 is a complete DTMF receiver integrating both the bandsplit filter and digital decoder functions. The filter section uses switched capacitor techniques for high- and low-group filters and dialtone rejection. Digital counting techniques are employed in the decoder to detect and decode all 16 DTMF tone-pairs into a 4-bit code. External component count is minimized by on-chip provision of a differential input amplifier, clock-oscillator and latched 3-state bus interface.

• Complete receiver in an 18-pin package.
• Excellent performance.
• CMOS, single 5 volt operation.
• Minimum board area.
• Central office quality.
• Low power consumption.