DRV2510Q1EVM: DRV2510EVM resistor function check

Marc Liu

Part Number: DRV2510Q1EVM

Hi Team,

For page 10 of https://www.ti.com/lit/ug/slou449/slou449.pdf, there are two resistors R6/R11 after two stages RC filters.

What's the use of these two resistors and how to choose the value. Thank you!

Marc

over 4 years ago

0 Luis Fernando Rodriguez S. over 4 years ago

TI__Guru* 84915 points

Hi, Marc,

I don't have much details on this, but it seems that the resistors R6 and R11 are used as part of the input filter to reduce the input level. I think it is used as a device protection for the PWM external level.

Please take a look at the captures below for details on the input filter frequency response with and without the resistor.

Input filter with resistor:

Input filter without resistor:

I also attached the TINA simulation in case it is required.

Input_filter.TSC

Best regards,
Luis Fernando Rodríguez S.

0 Marc Liu over 4 years ago in reply to Luis Fernando Rodriguez S.

TI__Intellectual 2850 points

Hi Luis,

Thanks for the reply!

I agree it can work as protection to reduce the input level with two stage filters. But from page 4 of http://www.ti.com/lit/ug/slou449/slou449.pdf, Figure 4 shows when J6/J9 is shorted, only 3.3k ohm res is on the wire.

Customer wonders if this is must if they don't need the RC filters. Thank you!

Marc

0 Luis Fernando Rodriguez S. over 3 years ago in reply to Marc Liu

TI__Guru* 84915 points

Hi, Marc,

The low pass filters are required for PWM input only. The idea of this filter is to reduce/eliminate all the high frequency content, which is not necessary in the device application.

Best regards,
Luis Fernando Rodríguez S.

0 Marc Liu over 3 years ago in reply to Luis Fernando Rodriguez S.

TI__Intellectual 2850 points

Hi Luis,

Sorry, I didn't say it clearly. What I mean is when no RC filter, is the 3.3k ohm pull down resistor still needed?

Thank you!

Marc

0 Luis Fernando Rodriguez S. over 3 years ago in reply to Marc Liu

TI__Guru* 84915 points

Hi, Marc,

Understood. The pull down resistor is not needed in this case. This is just a security connection for our EVM in order to avoid damage due to external voltage level. You may omit this resistor but just ensure that the absolute maximum ratings are not reached.

Best regards,
Luis Fernando Rodríguez S.

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DRV2510Q1EVM: DRV2510EVM resistor function check