Problems with pcb design

Hi,
I am new to pcb design. I am working at 220v. I have chosen track width as 86mil and clearance as 100mil. But the problem is the distance between two pins of an ic is around 100mil and these two pins has to be connected to 220v supply which did not satisfy clearance limit. Please help me with this problem.

Regards,
Suraj.

you can place copper pore to these to pines, but for that you should connect these pins by placing net-list connection.

Welcome suraj18,

suraj18 said:

I am working at 220v. I have chosen track width as 86mil and clearance as 100mil. But the problem is the distance between two pins of an ic is around 100mil and these two pins has to be connected to 220v supply which did not satisfy clearance limit.

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To be honest I don't understand this problem:

1. If the IC should be able to withstand 220V supply (=higher peak voltages btw) across two pins, then it will have enough clearance between those pins, right? No? Manufacturer slipped up in that IC's design? :?:
2. If the IC does NOT have enough clearance to have 220V supply across two of its pins, are you sure that's safe / proper thing to do? Is IC rated/specified for your intended application?
3. If those IC pins are just connected to 220V supply, but not have such voltage(s) across its pins, there's no problem. Clearance between conductors deals with voltages that can exist between those conductors (in normal operation / safety-wise), not voltages with respect to surrounding environment.
4. I hope you're not using that 100mil (2.54mm) as electrical safety distance between 220V mains & parts that users of the circuit can touch. If so (and it's a commercial product), please let us know model/type so that we know what to avoid.

Could you please post a schematic of the circuit you want to make a layout for? That would make it clearer to us why/where/what clearances are needed, or not.

Hi,

This is the schematic


Lsp3 and lsp4 are connected to 220v supply and T1(Triac) is the ic i am talking about.

Regards,
Suraj

i want see your layout where you facing problem...............??

Praveen Bhat

LSP1/LSP2 is touch-safe low voltage I assume? What's D5 for? And where's Vcc coming from?

Other than that I don't see much of a problem... Optocoupler should have plenty isolation between pin 1 & 2 on one side, and pins 4,5,6 on other side. And in usual pinout you have 2x pin-pin clearance (between pin 4 & 5, and again between 5 & 6), should be enough for 220V application. For the rest it's just:



Yellow line is safety clearance (I'd use 6 mm. clearance minimum).
Inside yellow line you might have 220V (AC? So some 300V peak) between tracks, anything >1 mm. clearance should be okay, more is better (not safety-critical). If T1 is rated for the voltage you're switching, don't worry about pin-pin clearance on T1. Just make clearances not smaller than between the pins on T1's housing.
Outside yellow line is touch-safe low voltage then (if LSP1/LSP2 are touch-safe, that is).

**broken link removed**

You have primary to primary clearence, and most importantly primary to secondary, there are internation guidlines for these clearences. The link above is a good source of info.
You also have to categorise your product due to pollution levels etc before you can determine the creepage and clearance distances.
Just remember when laying out high voltage and safety stuff, that YOU are responsible for enshuring the saftey of downstreem users of any products you have helped design.
Is it some sort of dimmer switch?