TCA8418E: TCA8418E column connection ( with 1kR between Colum & Key )

Cheung Wallace

Prodigy 10 points

Part Number: TCA8418E

Tool/software:

Hi all,

My question is any drawback or problem if i use the 1KR added between TCA8418E ( Key Scan IC ) and the Key.

Those 1KR was used the prevent the ESD.

Any drawback of it ? We just add 1KR column & the Key ( attached SCH photo for reference. )

13 hours ago

0 Clemens Ladisch 8 hours ago

Guru 256800 points

This forms a voltage divider together with the internal 55 kΩ pull-up. 1 kΩ probably is OK.

0 Tyler Townsend 1 hour ago

TI__Mastermind 26933 points

Hi Cheung,

The 1kohm resistors should be okay. Like Clemens stated, internal 55kohm pull-up resistors will form a resistive divider, but because 1k is a strong resistor, voltage divider will not be that big of an affect.

Regards,

Tyler

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TCA8418E: TCA8418E column connection ( with 1kR between Colum & Key )