FEATURES
u Line/speech circuit, loudhearing, handsfree and dc/dc converter on one 28 pin CMOS chip u Operating range from 13 to 100 mA (down to 5 mA with reduced performance) u Soft clipping control eliminating harsh distortion u Volume control of receive signal with squelch and automatic loop gain compensation u Line loss compensation pin selectable u Low noise (max. - 72 dBmp) u Real or complex impedance adjustable u NET 4 compatible u Dynamically controlled voice switching u Same monitor amplifier for loudhearing, handsfree and tone ringer u Very few external components u Power derived from ring signal by switching converter during ringing GENERAL DESCRIPTION
A switching converter is also provided for converting the ring signal. The AS2520 series incorporate volume control for the earpiece and the loudspeaker (AS2520 digital with +/keys and AS2521 analogue with potentiometer). The volume control circuit automatically compensates the loop gain to ensure acoustic stability. Typical Application La Package Available in 28 pin SOP and DIP.