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

2.5 Gbps PRBS Generator Schematics?

Status
Not open for further replies.

rfmw

Advanced Member level 2
Joined
May 10, 2001
Messages
545
Helped
93
Reputation
190
Reaction score
50
Trophy points
1,308
Activity points
3,978
prbs generator

have anybody been involved in designing a PRBS generator above 500 Mbps for test and measurement equipment for optical communications?

i want to design a 2.5 Gbps PRBS (2^7-1), but none experience in this field yet...

any schematics, links or tips about this welcome!

regards,
rfmw
 

Avii13

Newbie level 3
Joined
May 1, 2013
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Delhi
Activity points
1,304
Re: prbs generator

have anybody been involved in designing a PRBS generator above 500 Mbps for test and measurement equipment for optical communications?

i want to design a 2.5 Gbps PRBS (2^7-1), but none experience in this field yet...

any schematics, links or tips about this welcome!

regards,
rfmw


Hi,

I am facing the same problem and have to design a PCB for PRBS Generator. If you have solved your problem please help me. Any schematic or tips ??

Regards
Avii13
 

rfmw

Advanced Member level 2
Joined
May 10, 2001
Messages
545
Helped
93
Reputation
190
Reaction score
50
Trophy points
1,308
Activity points
3,978
How do you plan to design a PRBS core, in an IC or using discrete logic chips?
 

FvM

Super Moderator
Staff member
Joined
Jan 22, 2008
Messages
47,209
Helped
13,984
Reputation
28,217
Reaction score
12,626
Trophy points
1,393
Location
Bochum, Germany
Activity points
274,941
Discrete LFSR upto about 3 GHz should work with Onsemi MC100EP logic series. XOR propagation delay 250 ps, FF setup 50 ps.
 
  • Like
Reactions: Avii13

    Avii13

    points: 2
    Helpful Answer Positive Rating

Avii13

Newbie level 3
Joined
May 1, 2013
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Delhi
Activity points
1,304
Discrete LFSR upto about 3 GHz should work with Onsemi MC100EP logic series. XOR propagation delay 250 ps, FF setup 50 ps.
Yes, I'm using discrete IC's and the same series. In my project I have to provide clock to two 2^7-1 PRBS with single clock source. As a clock driver I'm using insemi's NB100LVEP221. the output of two PRBS are fed to MUX to get a 1.25 Gbps output rate.

For clock I"m using onsemi's NBXSBA024 crystal Oscillator.

Actually I'm new to PCB designing so not able to decide how to proceed.

Pins of IC which are not of use should be left open or should be connected to ground??
I need help to complete the project on time..
 

rfmw

Advanced Member level 2
Joined
May 10, 2001
Messages
545
Helped
93
Reputation
190
Reaction score
50
Trophy points
1,308
Activity points
3,978
NC pins can be left open. FR-4 laminate is sufficient for 2.5Gbps. Use as much differential transmission lines as possible. Make a careful (on paper) design of all setup and hold times, and delays for the clock distribution circuit.

Your plan is to mux two 1.25Gbps PRBS' into one 2.5Gbps. Why not using ONSemi's 10Gbps logic and go straight to the full-clock topology (clock=2.5GHz)?

In addition, try to use devices that have termination resistors in the chips. Making termination with 0805/0603 resistors is quite unfortunate, but necessary. Probably 4-layer PCB will be a must.

FvM: what about the FF's prop delay?
 
Last edited:
  • Like
Reactions: FvM

    FvM

    points: 2
    Helpful Answer Positive Rating

FvM

Super Moderator
Staff member
Joined
Jan 22, 2008
Messages
47,209
Helped
13,984
Reputation
28,217
Reaction score
12,626
Trophy points
1,393
Location
Bochum, Germany
Activity points
274,941
what about the FF's prop delay?
Good point. You see, that I didn't actually implement a design. Propagation delay seems to enforce usage of 10 GHz NB7xx logic series.
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top