DESCRIPTION

The circuit provides DC loop termination for analog trunk lines.

The V-I characteristics is equivalent to a fixed voltage drop (zener like characteristic) in series with an external resistance that determines the slope of the DC characteristic.

An external low voltage electrolytic capacitor causes the circuit to exhibit a very high impedance to all AC signal above a minimum frequency that is determined by the capacitor itself and by a 20 K nominal resistor integrated on the chip.

■ ON CHIP POLARITY GUARD

■ MEETS DC LINE CHARACTERISTICS OF EITHER CCITT AND EIA RS 464 SPECS

■ PULSE FUNCTION

■ HIGH AC IMPEDANCE

■ OFF HOOK-STATUS DETECTION OUTPUT

■ LOW EXTERNAL COMPONENT COUNT