ESD Protection in mini PCIe card

[ctzof]

I am building a half mini PCIe card that has a microcontroller which can be connected to PC and communicate with it with USB connection. On the same time many other pins of the microcontroller are connected to the pins of the card because I want to use this card as a standalone board. The question is do I have to use esd diodes to all pins of the card? Cause is nearly impossible because I don't have any space, or its not so crucial.

 

[malli_1729]

"all the pins of the cards" is it mean pins on PCIe edge connector.........This connector during operation is not exposed outside for ESD. there is no specific requirement of ESD on these pins.......

 

[ctzof]

"all the pins of the cards" is it mean pins on PCIe edge connector.........This connector during operation is not exposed outside for ESD. there is no specific requirement of ESD on these pins.......

Exactly means the pins on the edge connector. So it doesn't need any protection during plugging and unplugging the card like regular USB stick for example?

 

[malli_1729]

Yes.....They don't require any ESD protection........

 

[ctzof]

Last question....The reason I am concern is that large spikes can be created during plugging and unplugging of the card so the ESD protector diodes should be there to protect the board from these spikes, isn't that true?

 

[malli_1729]

The PCI system is designed for handling this.
in PCI system, the all add-in cards will have pins with different lengths. there are PRSNT pins which are of less length compared to other pins. Because of this during connecting, these pins will mate last after that only Host detects card and enables power, so, they are as per intended operation. During un-plugging, these pins are first to un-mate. So, immediately Host will remove the power.
in addition to it, Hosts will have lot of intelligence in power.

 

[malli_1729]

Still if u have doubt in this.....It's better to read electrical specfications of PCI system.......... I have seen in few systes they will use ESD components mostly MOV's/ESD suppressors on only rails (12V and 3.3V on PCIe edge, if u use them to power your system). Fuses on 12V and 3.3V also helpful for reducing damage(during short circuits in boards)