INA3221: input capacitance

Bruce li

Part Number: INA3221

Dear TI Experts,

Could you kinldy provide the input capacitance of VIN+1/VIN-1；VIN+2/VIN-2；VIN+3/VIN-3 Pins? We can find it from datasheet, thanks.

over 6 years ago

0 Peter Iliya over 6 years ago

TI__Mastermind 32395 points

Hey Bruce,

I am working on this now and will be back with an soon.

Sincerely,

Peter

0 Peter Iliya over 6 years ago in reply to Peter Iliya

TI__Mastermind 32395 points

Hey Bruce,

May I ask why this parameter is important for your design? Usually input capacitance is important when loading the inputs with resistors and this creating time constants for either the VBUS or VSHUNT signals; however, we don't recommend input resistors anyway as this will affect accuracy (section 8.4.3 of datasheet). I would not expect input capacitance to be greater than several pF, but I am still working on confirming this.

Best,

Peter

0 Bruce li over 6 years ago in reply to Peter Iliya

Genius 5580 points

Hi Peter,

Thanks a lot for your help, customer is designing a high speed(100MHZ) digital circuit which will connect with INA3221. So they need to know the detail about this parameter.

0 Peter Iliya over 6 years ago in reply to Bruce li

TI__Mastermind 32395 points

Hey Bruce,

Well if they are trying to measure 100MHz current, then they will want to pay attention to section 8.4.3 of datasheet. Current transients at harmonics of 500kHz can give the internal ADC problems. If they would want to measure average current they could use a RCR differential input filter to average the shunt voltage signal.

Best,

Peter

0 Bruce li over 6 years ago in reply to Peter Iliya

Genius 5580 points

Hi Peter,

Thanks for your suggestion, I'll discuss with customer further

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INA3221: input capacitance