Driving NXP MRF-101 only with 15dBm

[Robin Ivetic]

Hello,

I like to know how much power in watts or dBm, I can get if I can supply only 15dBm at RF input, and I don't want to attach pre-drive before, it's beginners question but maybe Jim you made tests in laboratory environment before.

And another question, can I run fet MRF101AN 24/7 without heating issue.

You where at help before, maybe you would know the answer.

Robin

 

[jcve...@gmail.com]

Hi Robin,

The MRF101 amp is a linear amplifier with 18-20 dB gain depending on the frequency, bais and other factors. So if you supply 15 dBm you would expect to see 18-20 dB higher output or 33-35 dBm (2-4 watts). The driver amp all by it's self will provide the same output without a MRF101 since it has the same gain and it's max output is 5-6W

Whether or not you can operate 24/7 with the amp depends entirely on the heatsink you attach to the amp. For safe/reliable operation, you need to keep the MOSFET flange temp below 50C°. If your ambient temp is 25C°, that's a 25C° rise. At 100W output the MRF101 dissipates as much as 75W so you need a heatsink with a thermal resistance of < 0.33°C/W which is achievable with a fairly large convection heatsink or a modestly sized forced air heatsink.

73,

Jim WA2EUJ

[jcve...@gmail.com]

Hi Robin,

The AFT09MS015 running in the driver is a different situation. The max junction temp is 150 °C and it has a 1°C/W thermal resistance that means that a case temp of 70 or 80°C isn't damaging. It's also running at 1/3 of it's rated power.

73,

Jim WA2EUJ