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

digital bit through 0ohm???

Status
Not open for further replies.

ljy4468

Full Member level 4
Joined
Jul 20, 2005
Messages
232
Helped
13
Reputation
26
Reaction score
1
Trophy points
1,298
Location
South Korea
Activity points
3,023
Hi everyone?

I've seen TI ADS5500 Evaluation board.(pipeline ADC 14bit 125MS/s)
and all digital output, clk output pass 0-ohm resistor.

why digital signal pass 0-ohm resistor?
what's the effect?

please tell me why.
thanks in advance.
 

philba

Full Member level 2
Joined
Jan 26, 2006
Messages
132
Helped
13
Reputation
26
Reaction score
1
Trophy points
1,298
Activity points
3,102
there is no such thing as 0 ohms. all material has resistance except at superconductor temperatures.

Typically, "0 ohm" resistors are used for several purposes. One is just a jumper to allow creation of a single sided board (or perhaps a fewer layer board). Thompson TV sets are notroious for this. Another use is in a place where a resistor might be used in certain circuit configurations but others the resistor is not needed (and thus 0 ohms is used). It allows a manufacturer to create a single PCB to be used in multiple configurations/products.
 

Uky

Member level 5
Joined
Sep 3, 2004
Messages
83
Helped
18
Reputation
36
Reaction score
4
Trophy points
1,288
Location
Swedish West Coast
Activity points
1,205
Very typical during initial layout spins in order to be certain that different configurations can be tried.

If there are high-speed signals involved, the zero Ohm resistors can be replaced with "real" values in order to evaluate different driver impedances in order to minimize signal integrity problems.
 

ljy4468

Full Member level 4
Joined
Jul 20, 2005
Messages
232
Helped
13
Reputation
26
Reaction score
1
Trophy points
1,298
Location
South Korea
Activity points
3,023
Oh thanks!
But I've a question more.
In Analog device's evaluation board(ADC)
there are 22 ohm resistor instead of 0 ohm.....
I want to know more.

thanks
 

philba

Full Member level 2
Joined
Jan 26, 2006
Messages
132
Helped
13
Reputation
26
Reaction score
1
Trophy points
1,298
Activity points
3,102
hard to say exactly but I bet its a current limiter
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top