The Tektronix P6202 is a 500 MHz active 10× FET probe with 50 Ω output impedance, introduced in 1976.
|Bandwidth||DC to 500 MHz (16 Hz lower limit with additional AC coupling tip)|
|Rise time||< 0.7 ns|
|Attenuation||10 : 1 (100 : 1 with additional 10× attenuator tip)|
|Input impedance||10 MΩ // 2 pF with or without additional 10× attenuator tip, +2 pF for AC coupling tip|
|Input range||± 6 V (± 60 V with additional 10× attenuator tip)|
|DC Offset range||± 55 V (± 200 V with additional 10× attenuator tip)|
|Max input||± 200 V (nondestructive)|
|Signal cable length||2 m (6.5')|
An initial 8 MΩ : 2 MΩ divider drives a dual JFET (source follower + current source), a PNP emitter follower and finally an NPN emitter follower as a cable driver. These stages use SMD components located in the probe tip. The probe control box at the end of the coax only contains a ±7 V regulator, a switchable 50 Ω terminator, and the offset potentiometers that supply ±15 V to the bottom of the input divider. There is no input protection apart from the divider.
Rise time of a P6202 500 MHz FET probe measured on a 7S12 plugin in a 7844 mainframe (with 25 ps S-52 pulse generator head and 25 ps S-4 sampling head). Measured rise time ~440 ps observed on this specimen is equivalent to 795 MHz bandwidth.