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TIDA-00913: Filter for INA240

Part Number: TIDA-00913
Other Parts Discussed in Thread: INA240, TMS320F28069M

Hello,

In the TIDA-00913 reference design, there is a RF filter in the output of INA240 and there is no input filter before the INA240.

1-)When should we use that RF(output filter)? can we remove that?

1-)Is that RF filter in the output of INA240 enough for noise filtering? When do we need input filter for INA240?

Regards,

Mohammad.

,

  • Dear Mohammad,

    Thank you for your interest in INA240 and the TIDA-00913 TI design. Please find my feedback below.

    Output filter: We used a small RC filter of 20 Ohm and 2.2 nF to drive the TMS320F28069M integrated ADC's switch capacitor input. The typical S/H capacity of TMS320F28069M ADC is around 1.6pF, and the 2.2 nF ensure we charge to around 0.1%.

    Input filter: The INA240 data sheet notes: "Input filters are not required for accurate measurements using the INA240, and use of filters in this location is not recommended. If filter components are used on the input of the amplifier, follow the guidelines in this section to minimize the effects on performance". Please refer to the data sheet section 9.1.1. for more details.

    Regards,
    Martin Staebler