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.

Help me compare two circuits and decide which is better

Status
Not open for further replies.

mouzid

Full Member level 5
Joined
Jun 22, 2007
Messages
248
Helped
9
Reputation
18
Reaction score
0
Trophy points
1,296
Activity points
2,876
Hello,
Please see the figure below.
Are these two circuits equivalents?
Which one is better ? Why ?
 

Equivalence

Hi,
The second one coz its layout is smaller if compared to the second.
 

    mouzid

    Points: 2
    Helpful Answer Positive Rating
Equivalence

it's dependent on your application and layout. If you want good matching of DFFs, I think the second one is better. in the first scheme, two input of DFF may show some difference as the mismatching of the INVs.
 

    mouzid

    Points: 2
    Helpful Answer Positive Rating
Re: Equivalence

Your schematics are incomplete as to say which one is better. Whenever flipflops comes into picture clock comes into account. Clock routing or simulations are most critical regarding matching parasitics in layout designing or balancing the skew for PNR blocks.

If the output of the inverters/buffers are going to the CLK pin of the flipflop then 1st schematic should be considered as it serves the purpose for both layout designing & PNR block. But if the output is going to any pin then 2nd schematic is better as it saves area for layout designing and for PNR block it reduces additional net delays & net routings.
 

    mouzid

    Points: 2
    Helpful Answer Positive Rating
Re: Equivalence

Paramjyothi said:
Your schematics are incomplete as to say which one is better. Whenever flipflops comes into picture clock comes into account. Clock routing or simulations are most critical regarding matching parasitics in layout designing or balancing the skew for PNR blocks.

If the output of the inverters/buffers are going to the CLK pin of the flipflop then 1st schematic should be considered as it serves the purpose for both layout designing & PNR block. But if the output is going to any pin then 2nd schematic is better as it saves area for layout designing and for PNR block it reduces additional net delays & net routings.

I'm talking in general. I wanna know the difference between the 2 circuits in terms of area, delays, skew, input capacitances, layout etc when the output of inverter are going to DFF clock pins or when they goes to anoher pins.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top