FR4 and What does Drip Electronics use?

Hey, I guess this is the right spot for this.

I'm using PCB artist and it's asking me what material I want to use for the board. It gives me an option such as FR4.

What are my options here?

What are the best and most insulated "RF proof" materials?

What software and materials does Drip Electronics use for their boards? 

FR4 (fire resistant) is pretty common, I am not aware of any RF proof PCB stock, but I guess you could engineer some extra shielding by using a multi-layer board and dedicating an internal layer as a shield.

I am not sure who Drip electronics is so I don't know what they use, maybe ask them.

JR

JohnRoberts said:

FR4 (fire resistant) is pretty common, I am not aware of any RF proof PCB stock, but I guess you could engineer some extra shielding by using a multi-layer board and dedicating an internal layer as a shield.

I am not sure who Drip electronics is so I don't know what they use, maybe ask them.

JR

Click to expand...

In my limited experience I used the ground plane on the same layer as my heater traces. I think what I'm mostly curious about is how to design the most optimized tube PCB's.

Thanks for the reply JR,

-JP

FR4 is probably the most commonly used PCB material in the world. It is basically glass fibre and is used for nearly all double sided and multi layer PCB. The other common material is SRBP (synthetic resin bonded paper) which tends to be used in low cost consumer single sided boards because it is less than half the price of FR4. There are other single sided materials that are now bwcoming more common.

For groupdiy type of devices, FR4 is all you need.

Cheers

Ian

Synthetic resin bonded paper - FR3 - to be preferred for cnc-routed (as opposed to etched) diy pcb's

Jakob E
(who just got a LPKF 101 Hi-P system)

Is there any difference to pay attention between both of them? I mean, any of them could bring any problems the other doesn't or at least in a lower proportion, resistance or capacitance? FR3 and FR4 are the most common, but I never seen a comparison between them, does FR3 add any parasitic component FR4 doesn't? Or is the difference just in mechanical behavior and the fire resistance?

I almost always used FR3 since FR4 is harder to get close, is there any problem with it in circuits that won't catch fire (low power divides)?

JS

joaquins said:

Is there any difference to pay attention between both of them? I mean, any of them could bring any problems the other doesn't or at least in a lower proportion, resistance or capacitance? FR3 and FR4 are the most common, but I never seen a comparison between them, does FR3 add any parasitic component FR4 doesn't? Or is the difference just in mechanical behavior and the fire resistance?

I almost always used FR3 since FR4 is harder to get close, is there any problem with it in circuits that won't catch fire (low power divides)?

JS

Click to expand...

Check any broadcast equipment of companies like Sony, JVC, Panasonic etc. Literally the 99% of all analogue circuitry  whether RF or Audio is built on FR3,  and "all digital" circuitry is on FR4. 

Also the portable/hand held radios since the early transistor.

So the lesson I take from this is that if we put the uber high frequency application aside, if the capacitance was a big factor then they would not have used FR3 for RF.  I think it is all about what you can get away with in terms of cost vs the design demands.

Join an EMC forum  ;D

Drip's info says that they use thick .093" FR4 pcb with 3oz copper plating.

I have a couple of them and they are heavy-duty stuff.

regards, Jack

sahib said:

Check any broadcast equipment of companies like Sony, JVC, Panasonic etc. Literally the 99% of all analogue circuitry  whether RF or Audio is built on FR3,  and "all digital" circuitry is on FR4. 

Also the portable/hand held radios since the early transistor.

So the lesson I take from this is that if we put the uber high frequency application aside, if the capacitance was a big factor then they would not have used FR3 for RF.  I think it is all about what you can get away with in terms of cost vs the design demands.

Click to expand...

Even then, I think the main reason is not electrical.  FR3 has less copper adherence than FR4, so FR3 doesn't lend itself for ultra-fine resolution that is usual in digital stuff.

So, FR4 is really preferred in the case of small traces or mechanical stress or high power/temperature applications to avoid fire, for other uses may not be a real difference and we are just as fine with FR3 than FR4...

Thanks
JS

joaquins said:

So, FR4 is really preferred in the case of small traces or mechanical stress or high power/temperature applications to avoid fire, for other uses may not be a real difference and we are just as fine with FR3 than FR4...

Thanks
JS

Click to expand...

That's probably about right. The only other point i would make is that, unless things have changed a lot since I was stopped working 14 years ago, most PCB fabs will only do FR3 (SRBP) single sided i.e. no through hole plating.

Cheers

Ian

AMZ-FX said:

Drip's info says that they use thick .093" FR4 pcb with 3oz copper plating.

I have a couple of them and they are heavy-duty stuff.

regards, Jack

Click to expand...

Holy moses! That is definitely heavy duty. Even the thickest stack-ups we build at work are under 70mil. Then again, we do lots of RF, filters, and digital stuff...not high voltage tube.

therecordingart said:

AMZ-FX said:

Drip's info says that they use thick .093" FR4 pcb with 3oz copper plating.

I have a couple of them and they are heavy-duty stuff.

regards, Jack

Click to expand...

Holy moses! That is definitely heavy duty. Even the thickest stack-ups we build at work are under 70mil. Then again, we do lots of RF, filters, and digital stuff...not high voltage tube.

Click to expand...

  Not very uncommon. I've often used 2.4 and 3.2 mm (93 and 126mil) as opposed to the standard 1.6mm (63mil), whenever mechanical considerations justified it.
Silent arts use one of these thick versions for the backplane of their 500/51X chassis.

abbey road d enfer said:

therecordingart said:

AMZ-FX said:

Drip's info says that they use thick .093" FR4 pcb with 3oz copper plating.

I have a couple of them and they are heavy-duty stuff.

regards, Jack

Click to expand...

Holy moses! That is definitely heavy duty. Even the thickest stack-ups we build at work are under 70mil. Then again, we do lots of RF, filters, and digital stuff...not high voltage tube.

Click to expand...

  Not very uncommon. I've often used 2.4 and 3.2 mm (93 and 126mil) as opposed to the standard 1.6mm (63mil), whenever mechanical considerations justified it.
Silent arts use one of these thick versions for the backplane of their 500/51X chassis.

Click to expand...

We (day job) use a 0.093" board for a power supply. The design has many heavy modules so the extra thickness keeps the board solid.

-a

Thanks everyone. I always appreciate reading your responses.

Now I'm working on a regulated DC heater board. The transformer I selected is a 3 amp 10v secondary and now I'm sorting out track spacing. Advanced Circuits PCB Artist offers up to 0.012 inch spacing between the tracks and the ground plane.  This track spacing between my traces and ground just does not rub me the right way in such a high current situation.  Does it sound unacceptable to you more experienced PCB designers or am I right in feeling like PCB artist may be too limited to do the designs I want. I'm currently communicating with Advanced Circuits to figure out how to increase this. I should mention that this spacing also makes it difficult for prototyping with a ferric chloride style etch because the FeCl3 does not always take off such perfect and fine little pieces of copper. Larger iso gaps between the tracks and ground plane will surely increase my success rate with etching with FeCl3 and make it easier to solder without making any mistakes.

buildafriend said:

Thanks everyone. I always appreciate reading your responses.

Now I'm working on a regulated DC heater board. The transformer I selected is a 3 amp 10v secondary and now I'm sorting out track spacing. Advanced Circuits PCB Artist offers up to 0.012 inch spacing between the tracks and the ground plane.  This track spacing between my traces and ground just does not rub me the right way in such a high current situation. 

Click to expand...

Current is not an issue, voltage is. I would hesitate before applying mains voltage on a PCB with such a small clearance. I generally use 150 mil. But in your case, 10 Vac, it's perfectly adequate. In fact with 12mil, the dielectric strength of air being 75000V/inch gives a breakdown voltage of about 900V. It's even more if the PCB has a resist. But there are also many factors that converge to motivate the use of a larger clearance, such as contamination, humidity, geometry, manufacturing tolerances.
BTW, can't you make an island in the copper pour? or create a polygon that does not cover the areas where you think you have a problem?