On Friday, January 11, 2019 at 1:33:33 PM UTC-5, Winfield Hill wrote:> dagmargoodboat@yahoo.com wrote... > > > > This EPC GaN is the FET of my dreams, but it only > > exists in everyone else's dreams, too. > > Nightmare, 2x2mm passivated die with solder bumps. > > > -- > Thanks, > - WinSince I'm wrestling wire-bond parasitics trying to get my FETs /moving/, passivated die with solder bumps sounds fantastic. I just wish they'd start delivering them! Cheers, James Arthur
Linear power FETs
Started by ●January 10, 2019
Reply by ●January 11, 20192019-01-11
Reply by ●January 11, 20192019-01-11
On Friday, January 11, 2019 at 2:23:15 PM UTC-5, Gerhard Hoffmann wrote:> Am 11.01.19 um 02:58 schrieb dagmargoodboat@yahoo.com: > > > > > This little guy has Rth(jc) = .25K/W--pretty impressive. > > http://ixapps.ixys.com/DataSheet/de275_501n16a.pdf > > That's probably what has become of Directed Energy. > They bought die from APT IIRC and put them into their > freshly developed stripline case. > > They were the bee's knees some 15 years ago in ham radio > amplifiers but seem to have faded away, or I did not follow it > since my interest shifted to VHF+. > > cheers, GerhardCool. An internet search for "vhf fet PA power amplifier" brings up some interesting designs. Here's one: n=77% @ 2 meters, 500W https://www.researchgate.net/publication/309046370_ACKA_500_watt_power_amplifier_for_a_144_MHZ_channel_based_on_a_VHF_push-pull_power_mos_transistor As expected, RF guys just resonate out bond wire inductances, something I can't do when making fast pulses. Cheers, James Arthur Cheers, James Arthur
Reply by ●January 11, 20192019-01-11
On Friday, January 11, 2019 at 2:01:56 PM UTC-5, Winfield Hill wrote:> dagmargoodboat@yahoo.com wrote... > > > > This 650V part puts an enhancement-mode GaN FET in cascode with a > > depletion-mode GaN JFET. It's real, and it's kind of interesting too: > > https://www.transphormusa.com/en/document/650v-cascode-gan-fet-tph3206psb/ > > LMG3410R070, 600V 40A GaN, 100V/ns, integrated driver and protection. > > > -- > Thanks, > - WinThat's very interesting for power conversion and solid-state drives. Sweet. I have to make accurate fast rectangular pulses with flat tops and high edge timing accuracy, so for now I'm wary of having that much complexity between my trigger and the output signal. Thanks for the heads-up on a nice part. (I posted the linear-mode FETs partly with you in mind--ISTR you were interested Once Upon a Time.) Cheers, James Arthur
Reply by ●January 11, 20192019-01-11
<dagmargoodboat@yahoo.com> wrote in message news:7d99192c-fcde-4176-95d4-819c25ad0b6e@googlegroups.com...> Since I'm wrestling wire-bond parasitics trying to get my > FETs /moving/, passivated die with solder bumps sounds fantastic. > I just wish they'd start delivering them!??? EPC eGaN FETs have been around Digikey for half a decade IIRC! Tim -- Seven Transistor Labs, LLC Electrical Engineering Consultation and Design Website: https://www.seventransistorlabs.com/
Reply by ●January 11, 20192019-01-11
On Fri, 11 Jan 2019 13:40:22 -0800 (PST), dagmargoodboat@yahoo.com wrote:>On Friday, January 11, 2019 at 2:23:15 PM UTC-5, Gerhard Hoffmann wrote: >> Am 11.01.19 um 02:58 schrieb dagmargoodboat@yahoo.com: >> >> > >> > This little guy has Rth(jc) = .25K/W--pretty impressive. >> > http://ixapps.ixys.com/DataSheet/de275_501n16a.pdf >> >> That's probably what has become of Directed Energy. >> They bought die from APT IIRC and put them into their >> freshly developed stripline case. >> >> They were the bee's knees some 15 years ago in ham radio >> amplifiers but seem to have faded away, or I did not follow it >> since my interest shifted to VHF+. >> >> cheers, Gerhard > >Cool. An internet search for "vhf fet PA power amplifier" >brings up some interesting designs. > >Here's one: n=77% @ 2 meters, 500W > https://www.researchgate.net/publication/309046370_ACKA_500_watt_power_amplifier_for_a_144_MHZ_channel_based_on_a_VHF_push-pull_power_mos_transistor > >As expected, RF guys just resonate out bond wire inductances, something >I can't do when making fast pulses. > >Cheers, >James Arthur > >Cheers, >James ArthurRight. That's why RF dmos fets aren't good for pulses. Some are optimized for a specific RF band. 2 GHz is easy. DC to 2 GHz isn't as easy. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●January 11, 20192019-01-11
On Friday, January 11, 2019 at 3:05:14 PM UTC-5, dagmarg...@yahoo.com wrote:> On Friday, January 11, 2019 at 12:44:48 AM UTC-5, Phil Hobbs wrote: > > On 1/10/19 11:46 PM, dagmargoodboat@yahoo.com wrote: > > > RF MOSFETs. They're built for linear operation. At a glance, they seem > > > > Welcome back! You've been a bit scarce since last spring, iirc. > > > > Cheers > > > > Phil Hobbs > > Hi Phil! > > I've been doing some pretty fun things, but hobby-level > electronics, nothing I thought would be very interesting > for sed. I do still peek in to see what's happening.James!, As a tadpole here on SED I'd love to hear/see any of your hobby level 'fun' stuff. The fare has been a little thin here. I'm doing this high side switch driving a heater to ground. Looking at the circuit I got to work, I've got low pass filters everywhere, with little understanding... which happens sometimes when you're just trying to get something working. I think my circuit was missing some resistance on the inverting input. (I tried to do some asci art, but too much of a Friday night buzz. :^) High side GS resistor (on pfet) that is turned off by level sift 'grounded' base npn, with emitter resistor driven by opamp. A resistor divider senses drain/load voltage-compares that to error (in opamp) which drives emitter R. George H.> > Cheers! > James
Reply by ●January 12, 20192019-01-12
On 12/1/19 8:40 am, dagmargoodboat@yahoo.com wrote:> On Friday, January 11, 2019 at 2:23:15 PM UTC-5, Gerhard Hoffmann wrote: >> Am 11.01.19 um 02:58 schrieb dagmargoodboat@yahoo.com: >> >>> >>> This little guy has Rth(jc) = .25K/W--pretty impressive. >>> http://ixapps.ixys.com/DataSheet/de275_501n16a.pdf >> >> That's probably what has become of Directed Energy. >> They bought die from APT IIRC and put them into their >> freshly developed stripline case. >> >> They were the bee's knees some 15 years ago in ham radio >> amplifiers but seem to have faded away, or I did not follow it >> since my interest shifted to VHF+. >> >> cheers, Gerhard > > Cool. An internet search for "vhf fet PA power amplifier" > brings up some interesting designs. > > Here's one: n=77% @ 2 meters, 500W > https://www.researchgate.net/publication/309046370_ACKA_500_watt_power_amplifier_for_a_144_MHZ_channel_based_on_a_VHF_push-pull_power_mos_transistor > > As expected, RF guys just resonate out bond wire inductances, something > I can't do when making fast pulses.That paper, while only 5 years old, is using an LDMOS FET that's more than 20 years old. The analog TV transmitters it was made for have been retired locally after decades of service. Just sayin', our Indonesian fraternity might not be up with the very latest... and they don't show their circuits either. NXP publish a lot of good app notes and reference designs. Some of the RF power amps span well over a decade of bandwidth, limited mainly by the bandwidth of the baluns they use to transform between 50 ohms and 6 ohms (input) and 2-3 ohms output impedances. That's not really consistent with your claim that the lead inductances are just resonated out. If you look closely at the geometry of these transistors and at the reference designs themselves, in many cases the inductance starts to dominate over the capacitance only at some hundreds of MHz. So I don't think your complaint about RF FETs is entirely fair. Google for "site:nxp.com RF power" to get all the good info. The parasitics of a package that can produce 1800W CW over 1.8-400MHz must surely be rather small? <https://www.nxp.com/products/rf/rf-power/rf-ism-and-broadcast/1-600-mhz-broadcast-and-ism/1800-w-cw-over-1.8-400-mhz-65-v-wideband-rf-power-ldmos-transistor:MRFX1K80H> Clifford Heath.
Reply by ●January 12, 20192019-01-12
On Friday, January 11, 2019 at 5:37:21 PM UTC-5, Tim Williams wrote:> <dagmargoodboat@yahoo.com> wrote in message > news:7d99192c-fcde-4176-95d4-819c25ad0b6e@googlegroups.com... > > Since I'm wrestling wire-bond parasitics trying to get my > > FETs /moving/, passivated die with solder bumps sounds fantastic. > > I just wish they'd start delivering them! > > ??? EPC eGaN FETs have been around Digikey for half a decade IIRC! > > Tim > > -- > Seven Transistor Labs, LLC > Electrical Engineering Consultation and Design > Website: https://www.seventransistorlabs.com/You didn't read the OP, did you? That's okay, we all put our foot in it sometimes. :-) Cheers, James Arthur
Reply by ●January 12, 20192019-01-12
On Friday, January 11, 2019 at 6:58:36 PM UTC-5, John Larkin wrote:> On Fri, 11 Jan 2019 13:40:22 -0800 (PST), dagmargoodboat@yahoo.com > wrote: > > >On Friday, January 11, 2019 at 2:23:15 PM UTC-5, Gerhard Hoffmann wrote: > >> Am 11.01.19 um 02:58 schrieb dagmargoodboat@yahoo.com: > >> > >> > > >> > This little guy has Rth(jc) = .25K/W--pretty impressive. > >> > http://ixapps.ixys.com/DataSheet/de275_501n16a.pdf > >> > >> That's probably what has become of Directed Energy. > >> They bought die from APT IIRC and put them into their > >> freshly developed stripline case. > >> > >> They were the bee's knees some 15 years ago in ham radio > >> amplifiers but seem to have faded away, or I did not follow it > >> since my interest shifted to VHF+. > >> > >> cheers, Gerhard > > > >Cool. An internet search for "vhf fet PA power amplifier" > >brings up some interesting designs. > > > >Here's one: n=77% @ 2 meters, 500W > > https://www.researchgate.net/publication/309046370_ACKA_500_watt_power_amplifier_for_a_144_MHZ_channel_based_on_a_VHF_push-pull_power_mos_transistor > > > >As expected, RF guys just resonate out bond wire inductances, something > >I can't do when making fast pulses. > > > >Cheers, > >James Arthur > > Right. That's why RF dmos fets aren't good for pulses. Some are > optimized for a specific RF band. > > 2 GHz is easy. DC to 2 GHz isn't as easy.But I called out one, above, that's spec'd to tr=3nS @ 400V. That looked promising.> "N-channel enhancement mode linear RF power MOSFET > Ideal for class AB and C industrial, scientific, medical, and > commercial applications. > VDSS = 500 V ID25= 10 A" > https://media.digikey.com/pdf/Data%20Sheets/IXYS%20PDFs/IXZH10N50L2(A,B).pdfCheers, James
Reply by ●January 12, 20192019-01-12
On Friday, January 11, 2019 at 11:55:01 PM UTC-5, Clifford Heath wrote:> The parasitics of a package that can produce 1800W CW over 1.8-400MHz > must surely be rather small? > > <https://www.nxp.com/products/rf/rf-power/rf-ism-and-broadcast/1-600-mhz-broadcast-and-ism/1800-w-cw-over-1.8-400-mhz-65-v-wideband-rf-power-ldmos-transistor:MRFX1K80H> > > Clifford Heath.Excellent point. Yes, you'd think their parasitics would have to be small. "Unmatched" seems a promising magic keyword for pulse applications. I skimmed through the listings, but I didn't notice any that switch hundreds of volts, not even the RF Cooking transistors. I need that, at the moment. (I've made some of my own R.F. 'cooking transistors,' including my first and only +23dBm 920MHz p.a.)(Of which about 2e6 were ultimately produced.) One of my problems, currently, is that most of the high-voltage fancy FETs are monstrous compared to my needs, so even though their figures- of-merit Ron vs. Qg are worlds better than the older tech stuff, the fact that they're 20x over-sized for my application makes them slower than an appropriately-sized MOSFET. Even the most nimble GaN garbage truck FET still isn't as gamely as a silicon itty bitty unicycle FET. Cheers, James Arthur
