SSM-2120

a FEATURES 0.01% THD at +10 dBV In/Out 100 dB VCA Dynamic Range Low VCA Control Feedthrough 100 dB Level Detection Range Log/Antilog Control Paths Low External Component Count APPLICATIONS Compressors Expanders Limiters AGC Circuits Voltage-Controlled Filters Noise Reduction Systems Stereo Noise Gates Dynamic Range Processors/Dual VCA SSM2120/SSM2122 FUNCTIONAL BLOCK DIAGRAM V+ 36kΩ SIGNAL OUT CURRENT MIRRORS –VC +VC V+ V+ SIGNAL INPUT V+ 36kΩ IREF GENERAL DESCRIPTION V– The SSM2120 is a monolithic integrated circuit designed for the purpose of processing dynamic signals in various analog systems including audio. This “dynamic range processor” consists of two VCAs and two level detectors (the SSM2122 consists of two VCAs only). These circuit blocks allow the user to logarithmically control the gain or attenuation of the signals presented to the level detectors depending on their magnitudes. This allows the compression, expansion or limiting of ac signals, some of the primary applications for the SSM2120. PIN CONNECTIONS 22-Pin Plastic DIP (P Suffix) 16-Pin Plastic DIP (P Suffix) THRESH 1 1 LOG AV 1 2 CONOUT 1 3 SIGOUT 1 4 +VC1 5 CFT 1 6 22 GND 21 V+ 20 SIGOUT 2 19 +VC2 GND 1 SIGOUT 1 2 +VC1 3 CFT 1 4 16 GND 15 V+ 14 SIGOUT 2 SSM2120 18 CFT 2 13 +VC2 TOP VIEW –VC1 5 (Not to Scale) 12 CFT 2 11 –VC2 10 SIGIN 2 9 GND SSM2122 TOP VIEW 17 –VC2 –VC1 7 (Not to Scale) 16 SIGIN 2 15 RECIN 2 14 CONOUT 2 13 LOG AV 2 12 THRESH 2 SIGIN 1 6 IREF 7 V– 8 SIGIN 1 8 RECIN 1 9...