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Design >> Analog Design >> Delay element
https://designers-guide.org/forum/YaBB.pl?num=1189077463

Message started by dgsenthilkumar on Sep 6^th, 2007, 4:17am

Title: Delay element
Post by dgsenthilkumar on Sep 6^th, 2007, 4:17am

According to my knowledge there are only two types of delay cells are availabe, 1)inverter chain 2)current starved inverter. In this current starved inverter consumes less area but highly unstable across corners, and the other way for inverter chain. And because of this i gues mostly inverter-chain(or bit modification of that) is used. Is it correct?

Anybody knows about other types of delay cells? Because i could not get anything on this. Please give me reference if anyone finds.

Title: Re: Delay element
Post by packiaraj on Sep 6^th, 2007, 5:17am

Hello Senthil,
"Noise" is very important problem to be considered when Current Starved Inverter is to be used as delay cell in VCO/Frequency Synthesizer.
You might want to take a look at delay cell used in PLL which I guess is called as "Symmetrical PMOS Load delay cell". There are some ways to make it less sensitive to Process and Temperature variations.
Google " Low-Jitter Process-Independent DLL and PLL Based on Self-Biased Techniques" by John G. Maneatis.

Packiaraj.V.