Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

How to protect my LNA (5mA) in ISM band

Status
Not open for further replies.
H

HS

Junior Member level 1
Junior Member level 1
Joined
Jul 26, 2006
Messages
19
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
USA / Arizona
Activity points
1,468
My LNA (2.4GHz) has just 5mA Ic current, but the jungle of ISM band can hurt it a lot. How can I protect it?
I assume a PIN diode in front of the LNA will do the job, but how to implement it?
Can I find somewhere an application note regarding how to protect the LNA?
Thank you in advance to all people.
HS
 

Unless you are walking around on a military airfield with radars ablasting, you will not have a problem with the LNA being blown out by RF power at the antenna. The signals are too small by the time they reach your antenna. However, you might have a problem with static damage, so you might want a small inductor to ground somewhere between your antenna and LNA.
 

Springf2000 and biff44,
Thank you very much for your inputs of that nice PIN limiter and the reminder of the ESD.
I cannot believe I forgot to insert that RF choke to GND close to the antenna.
I am getting older for sure... :D
Regarding ESD, do you think that a 200 ohms transmission line shunt to GND tuned for the 2.4 GHz / 10mm long, might be a better ESD protection rather than a limitted in current inductor?

HS
 

that is good but it is not easy to tune
 

Do you have a series cap in between LNA and antenna ? The purpose is for dc blocking. It may also help. General speaking an transistor LNA won't so easy to be damaged by e.g ESD or picking up rf power through antenna. In fact, if the antenna ( e.g piece of metal wire ) short to gnd then it burns the LNA due to excess dc current



Rogerynt
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top