Hello,
we use a CMD309-P4 LNA in our design.
The datasheet indicates a maximum permitted power of +20dBm without specifying whether it is CW or pulsed.
Does a peak power of +25dBm lasting 400ns with a duty cycle of 0.2% max risk destroying our LNA?
Hi @Ludovic ,
You don’t need to worry about our chip’s 20 dBm max input power limitation because the OP1dB spec of CMD909P4 is 13 dBm. So LNA would be compressed until it reaches 20 dBm power level.
I suggest adding a Pi or T attenuator (with three resistors) between UWB IC and LNA. So, you can control the gain of the LNA by tuning the attenuation value if the gain of the LNA is excessive.
Kind regards,
Emre
Hi, We cannot add attenuation because we do not want to degrade the noise figure of the receive chain.
The elements which are in front of the LNA are a circulator to direct the Tx towards the antenna and an Rx filter to reject the Tx frequency.
The signal emitted is a pulse which lasts 1µs at +58dBm. On infinite ROS, all power returns to the LNA. The filter rejects the fundamental frequency of the Tx at -25dBm but the spectral content which is in the reception band is not rejected. We measured +25dBm peak at the time of the rising and falling edges of the pulse.
This makes 0dBm average with the duty cycle hence my question.
Hi @Ludovic ,
I thought your question was about DWM1001 but it looks like it doesn’t.
So I would suggest you send and e-mail to customer.support@qorvo.com about your enquiry.
Regards,
Emre