The LT1793 achieves a new standard of excellence in noise performance for a JFET op amp. For the first time low voltage noise (6nV/Hz) is simultaneously offered with extremely low current noise (0.8fA/Hz), providing the lowest total noise for high impedance transducer applications. Unlike most JFET op amps, the very low input bias current (3pA typ) is maintained over the entire common mode range which results in an extremely high input resistance (1013). When combined with a very low input capacitance (1.5pF) an extremely high input impedance results, making the LT1793 the first choice for amplifying low level signals from high impedance transducers. The low input capacitance also assures high gain linearity when buffering AC signals from high impedance transducers.