0
\$\begingroup\$

I have chosen 2 datasheets of MMIC Power Amplifier:

  1. HMC311ST89 MMIC AMPLIFIER – DC-6GHZ -16db Gain
  2. HMC637ALP5E – DC-6GHZ – 13db Gain

My intention is to use the 1st one as Power Amplifier. I was wondering whether I am going right because the 1st one description is GAIN-BLOCK whereas, the 2nd one is mentioned as Power Amplifier as per the respective datasheet.

\$\endgroup\$
  • 2
    \$\begingroup\$ Please link to the datasheets in your question. \$\endgroup\$ – pericynthion Jun 27 '17 at 17:24
  • \$\begingroup\$ You need to look at the 1dB compression point (or, alternatively, to third order intercept point) spec in the datasheets in order to make a decision. \$\endgroup\$ – Enric Blanco Jun 28 '17 at 9:58
3
\$\begingroup\$

Whether something is usable as a power amplifier depends on how much output power it can provide, and how much you need in your application.

Look at the P1dB metric in the datasheet for each amplifier. This tells you how much output power it can provide while just beginning to enter compression. (You can squeeze another dB or two out of it by driving it harder, but it will have less gain and more distortion, so the P1dB point is a good reference).

The HMC637ALP5E has a considerably higher P1dB than the HMC311ST89, so comparatively the former would be considered more suitable as a power amplifier. However, if you only need e.g. 15 dBm output power, it would be fine to use the HMC311ST89 as your final stage power amp.

\$\endgroup\$
0
\$\begingroup\$

"Power amplifier" is a relative term. if the device will output enough power for your application, into the intended load, and not violate any conditions in the data sheet, the it's a "power amplifier" for you.

Someone might consider 30dBm output a "power amplifier" and someone else might consider 0dBm a "power amplifier".

The gain term, 16dB or whatever is relative to the input signal, and subject to the condition that the output may not exceed a certain level in dBm. Ex: If we have a block with 16dB gain, and max output of 10dBm then we can't reasonably expect to feed it more than -6dBm. Feeding it 5dBm would still only result in 10dBm output, and may cause other problems.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.