input signal conditioning for DSO

[burningmosfet]

Dear all, I'm a little bit "rusty" with signal conditioning so, with the aim to review analog design, I would like to design a signal conditioning circuit for an oscilloscope input. I've not great expectations with bandwidth (<5Mhz) but I would like to input max 400V signals DC & AC with 1MOhm || 50pF employng opamp or bjt.

Is there any guidance or schematic for my applications ?

 

[schmitt trigger]

You want to design.............. a scope probe?
With that much voltage, it will be at least 10X, preferably a 100X one.

No need to have active devices. A resistor divider will do. And for those kind of voltages, it would be best if you go to 10Mohm.
Since the DSO's input has some capacitance, you'll have to factor a capacitor in parallel with the higher value resistor.

 

[burningmosfet]

Dear S.T., I don't need a probe, I would like to build the circuit between probe and the ADC of a DSO. Actually I use STM32F429 DISCO demo board with a modified fw for signal acquisition and visualization on two channel but the acquisition is (obviously) 5V limited.... I need something to vary voltage gain of input signal and at the same time have high impedance (1MHom)... presuming to use a 10x probe (9MOhm) between EUT and my circuit

 

[kisha9]

It was too lazy thank you