Help me compare two circuits and decide which is better

[mouzid]

Hello,
Please see the figure below.
Are these two circuits equivalents?
Which one is better ? Why ?

 

[AdvaRes]

Equivalence

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

 

[needforspeed]

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.

 

[Paramjyothi]

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]

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.

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.