Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic 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

Pulse Generator Source Impedance

Status
Not open for further replies.

infinite_gbps

Member level 3
Joined
May 11, 2009
Messages
59
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,804
I plan to use an Agilent 81111A Pulse Generator (with complementary outputs) to provide the control to my drive circuit for my SPDT switch. The SPDT switch can be found here:
http://www.triquint.com/prodserv/mor...rod_id=TGS2306

Pulse Generator here: http://www.metrictest.com/catalog/pd...s/hp_81100.pdf

Does my source impedance have to be 50Ohm for my drive circuit to control the switch? The setting on the source impedance can be 50Ohm or 1kOhm. I know it's an RF switch and the RF ins and outs are 50Ohm. Not sure about the control.

Thanks
 

biff44

Advanced Member level 5
Joined
Dec 24, 2004
Messages
4,836
Helped
1,354
Reputation
2,704
Reaction score
1,031
Trophy points
1,393
Location
New England, USA
Activity points
36,519
The unit has a display that shows output voltage. That display is ONLY accurate if you put either a 50 ohm or 1K ohm load on it, and select the appropriate command. If you do not have that correct load impedance...the actual voltage delivered to the load will have an error on it. That is not really a problem...you just have to set the unit to a different output voltage. The key here is to not have a voltage on the control pin higher than the switch can handle, or you might blow it up. Like if you told the unit to expect a 50 ohm load, but had a high impedance load instead.

If you plan on high speed switching, I would put a 50 ohm resistor to ground right at the switch, connect the switch to the pulser with a coax cable, and select 50 ohm load impedance. You will have accurate voltages, and less of a pulse reflection.
 

infinite_gbps

Member level 3
Joined
May 11, 2009
Messages
59
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,804
Attached is a jpg of my control circuit that goes to the switch. It will do 0 & -5V output differential from2.5 ns rise and fall 0-5V or 0-2.5V from pulse generator.

What do you think? 50Ohm setting or 1kOhm setting?

Thanks for the reply.
 

Attachments


Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top