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 improve P1dB of LNA?

Status
Not open for further replies.
S

steven_l

Member level 1
Joined
Jan 26, 2010
Messages
32
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,615
Friends, I am designing a GaAs LNA. Tech is WIN (Wireless Information Networking) 0.5um INGaAs pHEMT Enhancement/Depletion-Mode Device.

The LNA requires variable gain from 0dB~18dB, P1dBin >-10dBm@18dB, 0dBm@0dB. And working frequency between 400MHz---900MHz.
I tried many kinds of circuit, such as cascade with feedback (single stage), common source with feedback + common source with feedback., common source with source degeneration + common source with feedback.
But every circuit has -20dBm P1dBin.When I decrease the gain, P1dBout does not change
Usually the current is about 4mA for every stage, VG is about 0.3-0.4V, VD is about 2.5V for 3.3V VDD. The size is about 50*8 or 75*8

Who knows how to increase P1dBin of GaAs LNA?
 

Your LNA has a large bandwidth. Have you checked that the input and output matching (S11 and S22) are 50 ohms all over the band? In other words, your -20dBm P1dBin is always the same for all the bandwidth? Good matching mus be done with inductors and capacitors, and the gain can be increased with a higher output resistor (from +Vcc to drain-pin). Which value of resistor have you put?
Regards.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top