Integrated Circuits

The AS571D is Alfa’s version of the NE571 or SA571 in an SOIC package. AS571 is a versatile low cost dual gain control circuit in which either channel may be used as a dynamic range compressor or expandor. Each channel has a full-wave rectifier to detect the average value of the signal, a linearized temperature-compensated variable gain cell, and an operational amplifier. AS571 is well suited for use in VCA blocks, noise reduction systems, compandors/expanders ,etc. Features

• Complete compressor and expandor
• Temperature compensated
• Channel separation >86 dB
• Greater than 110 dB dynamic range
• Levels adjustable with external components
• Distortion may be trimmed out

Applications

• VCA
• High level limiter
• Low level expandor − noise gate
• Dynamic filters
• Dynamic noise reduction systems

The AS3109 is Alfa’s version of the Roland IR3109 VCF in an SOIC package. The AS3109 is a high performance voltage controlled four-pole filter. The four independent sections may be interconnected to provide a wide variety of filter responses, such as low pass, high pass, band pass and all pass. A single input exponentially controls the frequency over a range greater than 15 octaves with little control voltage feedthrough. AS3109 features high input impedance buffers. Features

• Voltage controllable range – 15 octaves
• Accurate exponential frequency scale
• High input impedance buffers
• Wide transconductance range
• Low input offset voltage
• Low control voltage feedthrough - 45 dB typical

Applications

• For electronic music