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Design >> Analog Design >> Maneatis partial-swing delay cell.
https://designers-guide.org/forum/YaBB.pl?num=1310973882

Message started by raja.cedt on Jul 18^th, 2011, 12:24am

Title: Maneatis partial-swing delay cell.
Post by raja.cedt on Jul 18^th, 2011, 12:24am

hello,
i have doubt regarding this delay cell. I know that one transistor in this pmos load has to be in triode region, because then only it will linear V-I characteristics. But if you see the replica bias i think because of the bias both both transistors in saturation region. Can any one please clarify this?

Thanks.

Title: Re: Maneatis partial-swing delay cell.
Post by loose-electron on Jul 18^th, 2011, 2:29pm

I have used the Maneatis delay cell in ring oscillators many times, but I did a redesign of the bias system

Title: Re: Maneatis partial-swing delay cell.
Post by neoflash on Sep 6^th, 2011, 5:37pm

loose-electron wrote on Jul 18^th, 2011, 2:29pm:

I have used the Maneatis delay cell in ring oscillators many times, but I did a redesign of the bias system

one thing I noticed is that anything I touched in its design will trigger a chain effect. The only exception is the charge pump.

Title: Re: Maneatis partial-swing delay cell.
Post by rajkumar palwai on Sep 29^th, 2011, 10:18am

Hi Raja,
You can understand maneatis cell in terms of current. Please see the attached figure. The figure plots the different current components of a maneatis cell w.r.to voltage across it.

The currnet through the current source transistor is shown in red color. The current thru diode connected is shown in blue curve. The average current (Itotal*0.5) is shown in black color. I have shown Itotal*0.5 current rather than Itotal, since it shows nicely how averaging is happening in the cell. Current will become some kind of linear across the voltage range and hence the cell acts as a linear resistor.

Title: Re: Maneatis partial-swing delay cell.
Post by rajkumar palwai on Sep 29^th, 2011, 10:20am

Forgot to add the figure

Title: Re: Maneatis partial-swing delay cell.
Post by rajkumar palwai on Sep 29^th, 2011, 10:23am

Hence the cell acts as a linear resistor only till the voltage where the cross over happens between two currents.