Sir,

The followings are spec. of 10073D Passive Probe

Bandwidth: 500 MHz

System risetime (calculated): <700 ps

Attenuation Ratio: 10:1

Input resistance: 2.2 MΩ (when terminated into 1 MOhm)

How can I calculate Probe Bandwidth ?

f3db not equal to 1/RC ?

R means input resistance, 2.2 Mohm,

C means input capacitance, 12 pF.

1/RC is about to 6 kHz that is far from 500 MHz,

What's relation between "bandwidth" and RC corner ?

The followings are spec. of 10073D Passive Probe

Bandwidth: 500 MHz

System risetime (calculated): <700 ps

Attenuation Ratio: 10:1

Input resistance: 2.2 MΩ (when terminated into 1 MOhm)

How can I calculate Probe Bandwidth ?

f3db not equal to 1/RC ?

R means input resistance, 2.2 Mohm,

C means input capacitance, 12 pF.

1/RC is about to 6 kHz that is far from 500 MHz,

What's relation between "bandwidth" and RC corner ?

At its core, the passive probe is a capacitively compensated resistor divider as shown in the attached schematic.This circuit has an input R of 2.2meg, input C of 12pf and a divider ratio of 10. When driven from a low impedance source, its frequency response is flat and the bandwidth has no limit.

However, in the practical world, there is some limit to its bandwidth. That limit is caused by parasitic components not shown in the schematic. The parastics can be altered with careful selection of components, the circuit layout and creative ways of adding components to cancel or minimize parasitics. Thus, one implementation of the circuit could have a higher bandwidth than another depending on the lengths the designer is willing to go to maximize bandwidth.

An added complication that occurs in passive probes, is that the connection between R2/C2 and R1/C1 is made using a coax cable. At the bandwidths of modern probes, the cable must be treated as a transmission line and techniques must be employed to handle the reflections that occur on the line.

It is these internal factors that determine the bandwidth of the final probe design. And they are not directly reflected in the input R and C characteristics of the probe.