wide dynamic range (50dB) DTMF Receiver with early DTMF tone detection and power down mode (4.19MHz Xtal) wide dynamic range (50dB) DTMF Receiver with early DTMF tone detection (4.19MHz Xtal) wide dynamic range (50dB) DTMF Receiver with Delayed DTMF tone detection and power down mode (4.19MHz Xtal) wide dynamic range (50dB) DTMF Receiver with delayed DTMF tone detection (4.19MHz Xtal)