I want to measure a bidirectional current using a Shunt and Current-Shunt Amplifier in High Side topology.
The ADC will work at a lower sample rate (<10 kSpS) than would be required for the faster parts of the signal (up to 500 kHz). Therefore a low pass filter between Amplifier and ADC will be used to prevent aliasing.
- Would an Amplifier with a Bandwidth smaller than than the fast signal components but larger than the sampling rate suffice (without a noticeable impact on the measuring)?
The bandwidth of most Current-Shunt Amplifiers seem to be in the range of 100 kHz to 400 kHz.
- Or do I need a Current-Shunt Amplifier with a Bandwidth of >= 500 kHz for this?
- I am not sure here if the Amplifier behaviour can be regarded as a low pass filter like the frequency response suggests. See the Gain vs Frequency plot of the LTC6104 for example (Page 4).
One reason I am asking is, that so far I only found Current-Shunt Amplifiers with a Gain of >= 50 but low bandwidth available in stock. The LT1999 for example has a high bandwidth and is available with a Gain of 50 but needs to be sourced directly from LT or as non-stock from Digikey.