IPP530 alternative?

[SA2CLC]

Hello.
My 11n90 class E 4-FET tx failed again, most likely due to a transient on the drains, anyway, was tired of that and I am looking into building something new and a H-bridge for160-80-40 seems promising. 

Looking at mouser and other vendors lists the IPP530 as obsolete. What are you guys recommending?

[vk3alk]

Hi Tommy...

Obsolete what a shame...
Personnally I thought at some stage this would happen and just before Covid purchased 50 of them at $1.10 each...
To me they were a gift from God really....
Even pushed them well beyond 150 volts and they just worked  

There is another FET IRFB4019PBF from Infineon....
They seem to be used in Class D audio Amplifiers whether or not thats good not sure...
Their specs are not quite as good but they will work as a replacement but probably not as a multi band 160 / 80 /40 transmitter ....
160 and 80M yes but 40M would probably have to be single banded....

They are not as robust in current rating either but 250Watts out of a single module should be OK...

If you do get some ( appox $3.00 each ) and they are successful would start to push them above 150 volts just to see where you stand with them...
Thats what I did with the IPPs .... applied modulation and slowly increased the Drain voltage but you do need overload protection otherwise everything goes....

250 watts out of a single module might not seem much but there are ways around this....

Have uploaded a photo of a module which has the PWM and TX on the one board...
The other photo shows 2 of them bolted together and then into say a 2 way power combiner will give you double the power...
It never stops really 4 into a 4 way combiner is a 1KW...
Each module loafs along as it has its own modulator and runs happly at 250 watts....  

You could even multiphase / interphase and get sampling rates in excess of 1Mhz  

I must say that with my current setups due to my Power Supplies each module runs at appox 125 Watts giving 250Watts output...
Are slowly building modules at the moment ( not in a great hurry ) and will Multiphase them...
This is not a Amateur Radio project but more as a Electronic project just to prove to myself that I can do it...


Wayne

[SA2CLC]

Wayne, that looks like a deal. Love the all-on-one board mod/tx.
Great work and nice layout.

Yeah, shame on the IPP530's. I see them on ebay from chinese vendors, but have got on the fake transistor train before so I'm very hesitant. Paypal refund is working good thou.

Looking at specs, I'm assuming rise and fall times are what to look at? Going surface gAn sure reveals some fast ones, with quite impressing voltage/current ratings, like the GS66508T, but that quickly turns expensive and more involved to mount and cool.
Maybe I'll order a couple 4019PBF's and try.

Couldn't you please do a writeup on your transmitter build?
// Tommy, SA2CLC

[vk3alk]

Wooww those GS66508T have impressive specs....
They are not all that expensive either but maybe I will stick with what I understand...
There is always something new appearing round the corner...

Will post something regarding the TX modules...
Just looking around at my test modules so I don't have to build from scratch...

Wayne

[SA2CLC]

Wayne, have a look at IRF200B211.
Pretty decent fall and rise times, fairly low output capacitance.
Cheap at about 1.5$

[vk3alk]

Yes they would be worth a try  

The price is good too....
I like Infineon they seem to provide all the specs  
Its current handling is about half the IPP...

What are your power levels in Sweden ?

[SA2CLC]

Yeah, I think I'll give it a try and order 4019PBF's and those 200B211's. Yeah, current rating is a bit low compared to IPP's, with higher RDSon. In my previous class E experiments, I still dont think that high current has been the cause of death of FETs. More likely due to high voltage spikes..
We're allowed 1kw pep, so two modules running at 250w carrier should hopefully share the current nicely. Have a 50v 15A supply, think I'll get another and series it with this giving 100v at 15A.
//Tommy

[vk3alk]

Hi Tommy

How lucky are you with those Power Levels ......
Your probably right about voltage spikes taking out your Class E ....
A 50 volt power supply... hmmm I'm curious about what modulation method you are using ......
I'm feeling a little nervous now ....
Could you tell me more about your system...


Wayne

[SA2CLC]

My old class E used this 50v psu (switcher) together with a pwm modulator (like the PUWMA).
100w carrier at 24v and around 5A if memory recalls correctly.

This time I'll series another psu with this to get higher voltage.
Modulator wise, we'll see what I'll use. For testing purposes and one H-bridge, my current pwm modulator might do, but I really like the idea of having it all on one board like you have shown
//Tommy

[SA2CLC]

Ok, so the more I look into datasheets, the more possible fets I find.

What determines the suitablility of a fet in a circuit like this?

Rise and fall times/delays.
Output capacitance?
Gate charge?


Looking at IPA50R280CE, which has nice ratings, (550v, 18A) but more turn off delay time than others (40 ns)
The output capacitance is low at 49pf,

What's your experience about this?

[vk3alk]

Probably all the things you mentioned....

Gate resistance ...
All the Gate charge characteristics
Drain to Source resistance
Gate capacitance
Thermal resistance

The IPA you mentioned I probably wouldn't order because its total gate charge and on resistance are higher... but who knows really unless you give them a go...
If everything is low than will purchase and test .... otherwise you will end up with so many FETs in your junk box...

[w9jsw]

I have been trying to look at other FETs than the IPP530 so I built a simple spreadsheet. Am I looking at the correct parameters? What are the most important ones? I assume input capacitance, current, dissipation... what would you prioritize.

I included a SI device that works well on 160 and 80 just for example - 16n50... The C3M0120 device looks best to me for a 40M tryout.

Any GaN devices I should include?

John

Updated to add Gate charge and thermal

[M0VRF]

Have a look at the GaNs from Transphorm.

They do a nice TO247 one now too along with the TO220 they've had for a while.

J.

[w9jsw]

JB,

I see that the TO247 has an included ferrite on the gate? Do you use a ferrite on the gate for the TO220 version?

Also, do you use RCdcl and RCsn circuits on your designs?

Looks like the TP65H070G4PS is the best choice for the circuit as it only needs a RCdcl and a Rg/FB on the gate, with a reasonable ~$8 cost.

Very comparable to the IPP530N15N with respect to gate capacitance. Better dissipation, voltage and max current. Cool.

John

[SA2CLC]

What strikes me is how (relative) slow they are (on-off delay, rise and fall times) compared to the IPP530. But, perhaps that has little impact. 100ns period equals to 10Mhz.

[steve_qix]

Hello.
My 11n90 class E 4-FET tx failed again, most likely due to a transient on the drains, anyway, was tired of that and I am looking into building something new and a H-bridge for160-80-40 seems promising. 

Looking at mouser and other vendors lists the IPP530 as obsolete. What are you guys recommending?

How are you driving your 4 FET transmitter?  Do you have TransZorbs across the drain bus to the source bus?  What is the total power supply voltage?

In almost every case (assuming a proper RF amplifier design, shunt capacitors, etc.), failures of this type are caused by parasitic oscillations.  These are usually a result of the physical layout.

Lesser causes are arcing in the antenna system or antenna coupler, or shunt capacitor failures.

Also, if using analog drive without TransZorbs on the gates, driver transients will cause failures.

Let us know.

[steve_qix]

The BSC520N15NS3 G would be a drop-in replacement, but unfortunately it is in a surface mount package.  Otherwise, looks almost identical to the IPP part.

[vk3alk]

Wooww very nice find Steve...
Have you looked at the part number .... very similar to the IPP and who knows could be the replacement  

I'm sure there is a reliable way to mount these things....
Don't like the thought of soldering the device to a heatsink pad of some kind but there are 4 bits for the Drain and 3 for the Source...
Maybe a little bit of copper bridging them and connectiong to the PCB perhaps...
Also have uploaded a photo showing a piece of Alumumin going across these FETs ... maybe something like that to attached to a Heatsink....
Can get them direct from an Australia source where I have an account so no problems there...

[w9jsw]

PC board application notes

[vk3alk]

Was a bit optimistic about those surface mount things ....

May as well buy proper RF transistors.... instead