LC73750

The LC73750 is designed as one kind of dialler LSI for both dual-tone multi-frequency (DTMF) and pulse telephone equipment. This single chip combines keyboard scanner circuitry, a dial signal generator, and a serial I/O interface. It provides dialling during power outages and featrues user-defined keys that are ideal for such applications as facsimile machines and cordless telephones with built-in answering machines.

Features of the LC73750 are:(1)uses CMOS technology capable of directly operating on the telephone line;(2)permits the use of a single-contact keyboard;(3)connects to the microcontroller via a serial I/O port (includes a built-in interrupt port);(4)includes a built-in oscillator circuit that can be used with a crystal oscillator or ceramic resonator;(5)includes a high-precision DTMF signal gnerator (+0.03%, -0.11%) that simplifiers the task of choosing a ceramic resonator;(6)generates 16 DTMF signals.

The absolute maximum ratings of the LC73750 can be summarized as:(1)maximum supplu voltage: -0.3 to +6.5 V;(2)maximum input voltage: -0.3 to VDD+0.3 V;(3)maximum output voltage: -0.3 to VDD+0.3 V;(4)power drain: 250 mW;(5)minimum load resistance: 1 k;(6)operating temperature: -30 to +70 ;(7)storage temperature: -40 to +125 . If you want to know more information such as the electrical characteristics about the LC73750, please download the datasheet in www.seekic.com or www.chinaicmart.com.