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

About PIN diode attenuator

Status
Not open for further replies.
L

lucky112

Newbie level 4
Joined
Dec 6, 2015
Messages
6
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
48
Hi, I'm now trying to analyze a PI attenuator circuit.

pin.jpg

Above pic is an ordinary PI attenuator using PIN diodes.
Everytime I googled it, almost every configuration is like the above pic.

dad.jpg

However, on the board of interest, the direction of PIN diodes is opposite.
The board used 'BAR 61' which consists of three PIN diodes.
The above pic is from the datasheet of BAR 61.

Could anyone tell me the difference between two configurations?
 

The difference comes from the supply circuit.When the diodes are forward biased then connected the resistances, the circuit acts as an attenuator with these resistances.
So the real attenuator consists of those resistances, the diodes act simply as switch these resistances.
The first picture is simplified principal circuit, it's not a real circuit.
 
BigBoss said:
The difference comes from the supply circuit.When the diodes are forward biased then connected the resistances, the circuit acts as an attenuator with these resistances.
So the real attenuator consists of those resistances, the diodes act simply as switch these resistances.
The first picture is simplified principal circuit, it's not a real circuit.
Click to expand...

Thanks for your reply. I have another question.
To pass through the series diode in the second picture, the signal has to be kind of 'negative signal'?
Because the reverse resistance of the series diode would be really big.
 

lucky112 said:
Thanks for your reply. I have another question.
To pass through the series diode in the second picture, the signal has to be kind of 'negative signal'?
Because the reverse resistance of the series diode would be really big.
Click to expand...
No, when the PIN diodes are forward biased with a DC current, they act as bi-directional switch.Don't consider them as ordinary diodes.
 
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top