Continue to Site

# Maximum input drive power(in dBm) for CGH40010F transistor

#### rd_dinesh

##### Junior Member level 3
The maximum input drive power for this power transistor from Cree is not explicitly mentioned in the data sheet.
How to calculate this?

Maximum input power for a GaN transistor is meningful only to not damage the transistor, and not for other paramaters as P1dB, which is an important parameter in LDMOS, BJTs, CMOS, or JFETs.
In GaN, if you look to the plots of gain vs output/input power, will see that GaN devices starts to compress at very low power levels, when other types compress right before saturation.

#### Attachments

• GaN.jpg
71.7 KB · Views: 16

Maximum input power for a GaN transistor is meningful only to not damage the transistor, and not for other paramaters as P1dB, which is an important parameter in LDMOS, BJTs, CMOS, or JFETs.
In GaN, if you look to the plots of gain vs output/input power, will see that GaN devices starts to compress at very low power levels, when other types compress right before saturation.
Okay, you say that we can operate it well beyond P1dB, but what is the maximum input power(in dBm) for safe operation.
I found a research paper using ~31dBm (which I calculated by subtracting gain from the output power, they reported)
So I decided to move with 30dBm
Any suggestions

The plots shown are 42 dBm - 18db = 24 dBm input max. So 30 dBm (1mW) is a bit high but possibly safe for an input without considering output temp rise.
--- Updated ---

Considering this is a FET, there is not much power dissipated in Rg at 1mW input, which is primarily absorbed by the external 47 or 50 R resistor, so this irrelevant to consider a limit for safety of the resistor in an FET spec.

Last edited:

what is the maximum input power(in dBm) for safe operation.
I found a research paper using ~31dBm (which I calculated by subtracting gain from the output power, they reported)
So I decided to move with 30dBm
Any suggestions

There is no information in the datasheet about safe maximum input power for this transistor.
Only the manufacturer can give you this information.

There is no information in the datasheet about safe maximum input power for this transistor.
Only the manufacturer can give you this information.
I think you missed my point/ The gate won't absorb much power since it is high impedance. There is only a V limit.

Points: 2