Marco Maria Monti

Low-noise tape preamplifier with new self-biasing architecture

Consumer electronics, like car radio applications, must work in single supply operations. In the meanwhile higher an higher performances are also required. This paper describes a low noise preamplifier, mainly intended for tape decks, with an unconventional self bias architecture that shows noise performances comparable with preamplifiers operating in double supply. This preamplifier is fabricated in a standard BiCMOS technology where offset free analog switches can be easily implemented guaranteeing pop free commutation in forward/reverse application. Measured value of input referred signal to noise ratio in the standard 20Hz 20KHz audio range is 300nV (A weighted) and THD is about 0.004% for maximum output voltage swing. The area of the whole stereo preamp is 2300 mils 2.