about pull up resistance issue

[wucaifeng]

To our Smart Card ic product, when set pull up resistance to 100KΩ, it will reset, can not work. what cause this iusse?

 

[kelvin_bao]

please tell us the problem more detailly.

 

[cnspy]

How do you know this problem is caused by pull up resistance?

 

[wucaifeng]

This issue is found when I test Vcc range.

Vcc=2.7v, pull up resistance=100KΩ, product will stop work; But when change pull up resistance into 20KΩ,product start to work again. change pull up resistance into 100KΩ, product stop work again.

 

[xworld2008]

Does the power is enough? When you pull up , may need more power,you can test the power consum. Or you layout have error , review you layout of the pull up resistance. The product you mean "sm card" or "sm card read"?

Added after 2 minutes:

if the product is "sm card",you can add power by outside to test it, and thought this you can find where is you error.

 

[wucaifeng]

whether it is caused by too little current or not?

 

[cnspy]

How about the load of this pin?

 

[xworld2008]

I think this is about you power and current, sm card get power and current from sm card read, so when you pull up resistant change to 100k, current change to small , at this time sm card can't get more current and power , so it will reset.