TPS560430: upper limit for the maximum allowed value of the resistor

Obinna Ezeilo

Part Number: TPS560430

Hi Team,

my customer is using a small resistor in series to the bootstrap capacitor (EMI) of the TPS560430YDBVR. Is there a upper limit for the maximum allowed value of the resistor e.g., 100 Ohm?

In the datasheet it is mentioned that the capacitor type should be ceramic X7R with a value of 100 nF and > 16 V. Does also exists a range of the capacitance

in which the full functionality of the step down convert is guaranteed e.g., 47 nF .. 220 nF?

Thanks,

Obinna.

over 4 years ago

0 J Arrigo over 4 years ago

TI__Mastermind 28020 points

Hi Obinna,

I will need to check with the design team and get back to you.

Thanks, Jason

0 J Arrigo over 4 years ago in reply to J Arrigo

TI__Mastermind 28020 points

Hi Obinna,

For the series resistor, I would not recommend a value greater than 100Ω. If possible, start with a smaller value and increase if needed. The resistor will limit turn on speed, but will also reduce efficiency slightly.

The IC was validated using a 100nF, 16V capacitor for boot cap. This value is required for operation.

Regards, Jason

0 Obinna Ezeilo over 4 years ago in reply to J Arrigo

TI__Intellectual 2385 points

Hi Jason,

For the capacitor they will use a 100 nF / 16 V X7R type. Based on the tolerance, DC-bias, temperature dependency

etc. the range of this capacitor is between 47 nF and 150 nF. Could they use this capacitor to guarantee the full functionality

of the step down?

Or could you define a range of this bootstrap capacitor so that they could find a capacitor which will fit.

Thanks,

Obinna.

0 J Arrigo over 4 years ago in reply to Obinna Ezeilo

TI__Mastermind 28020 points

Hi Obinna,

Yes, the 100nF, 16V, X7R capacitor can be used for full functionality of this application.

Regards, Jason

0 Obinna Ezeilo over 4 years ago in reply to J Arrigo

TI__Intellectual 2385 points

Hi Jason,

Can you inform on lower and upper limit ranges for the capacitor selection?

Thanks, Obinna.

0 J Arrigo over 4 years ago in reply to Obinna Ezeilo

TI__Mastermind 28020 points

Hi Obinna,

A 100nF capacitor must be used. Even though the effective capacitance may be different due to tolerance, DC-bias, temperature dependency

etc., 100nF was the only value the device was validated over.

Regards, Jason

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TPS560430: upper limit for the maximum allowed value of the resistor