EMRFD Message Archive 12968

Message Date From Subject
12968 2016-06-24 18:25:25 shaynal01 New RF transistor for QRP PA

DigiKey is now carrying the AFT05MS003N. See

 AFT05MS003NT1 Freescale Semiconductor - NXP

12969 2016-06-24 19:18:08 cx2am Re: New RF transistor for QRP PA
Good news MNY TNX 73 de CX2AM
12970 2016-06-24 19:41:06 Don AE5K Re: New RF transistor for QRP PA
DigiKey has zero stock, Mouser has plenty and less cost.

12971 2016-06-25 08:11:03 shaynal01 Re: New RF transistor for QRP PA
Digi-Key lists 23,000 as "Factory Stock." This is stock that is available at the supplier which may be available to Digi-Key upon receipt of order. It is good to know that Mouser has these too at a lower cost.



12972 2016-06-25 21:38:21 Ashhar Farhan Re: New RF transistor for QRP PA
one reason why we love the IRF510 is it is pronounce and remember. try remembering AFT05MS003NT1 in the next eyeball meet.

- f

12973 2016-06-25 21:58:29 justin.kelly_n2to... Re: New RF transistor for QRP PA
has this part been used yet to build a push pull amp?
12974 2016-06-26 09:54:22 cx2am Re: New RF transistor for QRP PA
JAAAJAA yes! Why that name? Better 3NT1.
12975 2016-06-26 16:57:34 kb1gmx Re: New RF transistor for QRP PA
Yes that will be fun to use...

Its problems....

21db of gain though 900mhz and  at low HF expect 23-26db.  Stability will be fun to obtain.

ITs 3W devices if the tab is soldered to a large heatsink (remember its SOT89).  Having just done a two sided board for that kind of part (a similar one) that means a large pand to solder to and a lot of plated though vias 
to get the heat to the back where it can be (though suitable insulator) conducted away.

Long leads will make it a fine UHF oscillator.   Its not a drop in for IRF510 (or any IRF part).

At 3W its on;y 11X less capable of IRF510 power (43W).  Also its a 30V device which means 13.8V 
will be about 2X too high for swr survival.  Its wants to run at 7.5V.    FYI the SWR survival test runs
at 9.0V, higher is not as survivable.

It would make a good wide band single ended or push pull driver with feedback.
I might use it where I used 2N5109 (that is a 28V part) at lower voltage.

There are higher voltage and more robust parts in that series.
LDMOS parts in general are good RF performers with lots of gain and some can be 
extremely robust if used suitably.   

FYI that part will run down to audio.  Spec'd to 1.8mhz means that spic and parametric 
data is available down to there.

12976 2016-06-26 20:40:32 Dana Myers Re: New RF transistor for QRP PA
12977 2016-06-26 22:37:47 Ashhar Farhan Re: New RF transistor for QRP PA
This device is more particular useful in CW work. I didn't see any distortion data. I would guess a pair of 2N7000s could do just as well, producing 3 watts in push pull.

- f

12978 2016-06-27 04:56:15 kb1gmx Re: New RF transistor for QRP PA
Primary use at VHF and up is FM.

Distortion will vary with bias, as will gain.

It would be ideal for transmitters running at less that 9V.  Most HTs these days
are at 7.4v nominal (lithium ion batteries).

Look at their board layouts in the datasheet for how they want to mount it
and feed it.

That series has parts in the 6-12W range that might be more suitable but 
most FETs have no FT so even the IRF510 has substantial gain at 6M 
and up.  The limits if any come from lead inductance and capacitances 
of the junctions.  Most of that impacts broad band impedance match.

12979 2016-06-27 10:02:42 Ashhar Farhan Re: New RF transistor for QRP PA

I have often wondered (and done very little subsequently) if the 2N7000 would work at 144 MHz upto 1 watt? It seems to have the right capacitances. I am not tooled up to measure this very well, but I suspect it might work well.

- Farhan

12980 2016-06-27 10:57:13 Dana Myers Re: New RF transistor for QRP PA
12981 2016-06-27 13:32:42 Riccardo Montagut... Re: New RF transistor for QRP PA

I’ve found this link where vk2zay test the 2n7000 up to 144mhz as a PA but he say that beyond 90 Mhz doesn’t produce useful power, instead is usable below 70 Mhz.


Il giorno 27/giu/2016, alle ore 19:57, Dana Myers k6jq@comcast.net [emrfd] <emrfd@yahoogroups.com> ha scritto:

12982 2016-06-27 15:11:05 Sandeep Lohia Re: New RF transistor for QRP PA
don't know how to measure active input capacitance, does it also vary
with variation in frequency? datasheet only states at 1MHz

both the 2N7000 and BS170 are rated max 60 V fet ( 60 ÷ 4 = 13.8 safe
operating voltage ), capable of switching 200 mA (2N7000) or approx
500 mA (BS170), with a maximum on-resistance of 5 Ω at 10 V Vgs.

had both in my junk for class A QRP finals on lower VHF band,
vestigial side band...
but paralled 2 X BS170 simply because of it's more wattage & amp rating...

at approx 3 watt of RF voltage peak to peak is 34.5V in 50 ohm dummy,
still safe for the device...

& it's buffer driver was was BJT 2N3904,
as soon as I applied 12V, one out of two BS burst into 2, & I could
see internal metal flenge followed by little smoke, & heat therefore

IRF510 more thermal conductive but had little less output as compared
to it's input RF :D

well that was done back before 5 years, I'll be looking for VQ1000
dual in line package equivalent to 2N7000, in local market ( also
FQP1N50, FRP7N10, if I can find with local vender) also just because
of better thermal, & some readily available heatsink meant for LM
audio IC can aso be fitted to VQ1000...

Guys any idea which type of white ceramic is used inside MFR or CFR
resistance? its heat conductive, seen same on cheap 2 dollar BGY78a RF
module it's PCB was ceramic with some surface mount components,
same ceramic might be on outer part of hair-straightener.

beryllium oxide is toxic & don't even want liquid mineral or motor
oil in my dummy, solid ceramic in powder form or epoxy glue that
solidifies will be excellent , thermally conductive but electrically &
di-electrical or semi insulating compound, zinc- oxide?

any MFR or CFR is 3 to 4 turn inductor,
on some kind of white portelin ceramic material, ( googling didn't
help ) that ceramic composition or formula I actually want to know !

(mailed from mob)

12983 2016-06-27 15:28:34 Sandeep Lohia Re: New RF transistor for QRP PA
* BGY88


Please encourage recycling, reuse or repairing of E-waste.
░7░3░ ░d░e░ ░V░U░3░S░X░T░
12984 2016-06-28 14:57:26 davidpnewkirk Re: New RF transistor for QRP PA
Sandeep wrote:

don't know how to measure active input capacitance, does it also vary
with variation in frequency? datasheet only states at 1MHz

One way to determine the capacitance of a device is to ac-couple it to the tuned circuit of an oscillator operating at a known frequency with reasonably known values of L and C, observe how much the oscillator frequency changes, and then calculate how much net C was added to the oscillator by the coupled-in device (and its connections, which should be kept short, and its environment [power supply (which, if used, should be decoupled) and so on]).

Device internal capacitances don't vary with frequency, but they _do_ vary somewhat as the device's operating conditions (read: "voltages and currents") vary. This is the basis for such effects as _AM-to-PM conversion_.

Best regards,

amateur radio W9BRD
12985 2016-06-28 16:35:16 kb1gmx Re: New RF transistor for QRP PA
Input capacitance is measured at 1mhz using common gear that uses standard frequencies.

For the 2N7000 is on the datasheet.  For the most part its not frequency sensitive and only 
somewhat voltage sensitive.  You use the datasheet number at 1 or 100mhz.

The input of a POWER MOSFET is a complex thing as there is negative feedback from gate
to drain and the input capacitance from gate to source.  Its why the input impedance goes down 
with frequency.  Its only an effective open circuit at DC ( a high impedance).

FYI the white ceramic can be BeO or Alumina Both are safe of you do not abrade them or 
abuse them to make dust.  The Alumina (aluminum oxide) is intrinsic safe.  Both offer very low
thermal resistance.

FYI to get most mos fets to stand their rated current they must be saturated.  That generally 
only applies as switches.

FYI the IRF510 properly matched will produce more than a dozen 2n7000 in parallel.
I generally get about 55W from two in a push pull linear amp at 28V on 40 and 20.
I copied the OZ1PIF 250W module at 6M (4x4 push pull at 36V).  Run as a class E 
amp I've seen 20W from one at 12V and lots more at 24V. 

However most designs do not attempt to match and load it well enough to develop power
and it like 24-28V (not surprised as its a 100V device).  The IRF510 with a better thermal 
package could deliver much more.


12986 2016-06-29 14:08:40 Sandeep Lohia Re: New RF transistor for QRP PA
there's also FDT86256 ( QRP HF usage, less then dollar$ 1/- )
low output resistance < 1 ohm at 1.2A, max 2 amp if pulsed.
more rugged than BS170 even more as compared with 2N7000 and capable
of dissipating up to 10 watts if properly heatsinked...
with input gate capacitance just 55pf (as data sheet states)

btw with both SMD version of AFT05MS003NT1
& FDT86256 a ceramic thermal conductive with good heat spreading
characteristics (Al2O3), Aluminum Nitride (AIN), or Beryllium Oxide
(BeO) or best Alumina base material PCB is preferd rather then bad
conductor glass epoxy or paper phionolic based PCB

this will eliminate the need for direct connection of this SMD fets to
heat sinks, nor there's an option, as do I personally think.

FQP1N50 if I can find will test at 100 volts.

( mailed from mob )

bad, my little harmonic is in hospital, Break !