The AS Alfa 3340 VCO chip is Alfa’s modern version of the famous CEM3340 voltage-controlled oscillator. Now updated to the 3340a. The IC provides Ramp, Pulse/Square, and Triangle outputs, has inputs for hard and soft sync, is temperature compensated and stable, and provides excellent 1V/Oct tracking. It’s everything you need from an analog oscillator, on a chip. There's a reason this design is at the pulsing heart of legendary synthesizers from Moog, Roland, Sequential Circuits, Oberheim, and many many more. History of the Alfa 3340 The Alfa AS3340 is a voltage-controlled oscillator (VCO) integrated circuit (IC) that was first produced by Alfa Micro in the early 1980s. It is a direct replacement for the CEM3340, which was used in many classic analog synthesizers from the 1970s and 1980s. The AS3340 features a number of improvements over the CEM3340, including temperature compensation, improved 1V/Oct tracking, and a wider tuning range. It is also available in a smaller package, making it easier to use in modern synthesizer designs. The AS3340 has four output waveforms: triangle, sawtooth, square, and pulse. The triangle and sawtooth waveforms are buffered, while the square and pulse waveforms are unbuffered. The AS3340 also has two control inputs: a linear control input and an exponential control input. The linear control input can be used to vary the frequency of the oscillator in a linear fashion, while the exponential control input can be used to vary the frequency in an exponential fashion. The AS3340 is a versatile and powerful VCO that can be used to create a wide variety of sounds. It is a popular choice for synthesizer builders and musicians alike. Here are some of the features of the Alfa AS3340: Temperature compensated for stability Excellent 1V/Oct tracking Wide tuning range Small package Four output waveforms: triangle, sawtooth, square, and pulse Two control inputs: linear and exponential The Alfa AS3340 is a great choice for synthesizer builders and musicians who are looking for a high-quality VCO. It is a versatile and powerful IC that can be used to create a wide variety of sounds. Please note that Alfa recommends a 51K resistor on the pulse output in place of the 10K resistor that the original CEM 3340 VCO used. While the Alfa AS3340 VCO is an excellent choice for a new circuit, it should not be used to replace a vintage Curtis 3340, as there are differences between the way pulse width is handled. When replacing vintage Curtis Chips, I suggest purchasing reissued ICs from the Curtis Family. The datasheet is here: AS3340
