MC34014

The MC34014 is a kind of telephone speech network integrated circuit which includes adjustable transmit, receive, and sidetone functions, a dc loop interface circuit, tone dialer interface, and a regulated output voltage for a pulse/tone dialer. It also includes an equalization circuit which compensates gains for line length variations. MC34014 is available in a standard 18-pin plastic DIP and a 20-pin SOIC package.

There are some features of MC34014 as follows: (1)transmit, receive, and sidetone gains set by external resistors; (2)loop length equalization for transmit, receive, and sidetone functions; (3)operates down to 1.5 V (V+) in speech mode; (4)provides regulated voltage for CMOS dialer; (5)speech amplifiers muted during pulse and tone dialing; (6)DTMF output level adjustable with a single resistor; (7)compatible with 2-terminal electret microphones; (8)compatible with receiver impedance of 150 and higher.

What comes next is about the absolute maximum ratings of MC34014 (voltages referred to V-, Ta=25): (1)V+ voltage: -1.0 to +18 Vdc; (2)VDD (externally applied, V+=0): -1.0 to +18 Vdc; (3)VLR: -1.0 to V+ - 3.0 Vdc; (4)MT, MS inputs: -1.0 to VDD+1.0 V; (5)storage temperature: -65 to +150.