[SI-LIST] Re: On resistance of the driver and the input capacitance of receiver
- From: Rajat Chauhan <rajat@xxxxxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Tue, 12 Aug 2003 12:15:19 +0530
Hi Haritha,
A simple way to get an idea of your input capacitance using HSPICE is:
apply a constant current source at the i/p of your Recv. and check the
rate of increase of voltage at the i/p. Use I=C.dv/dt to calculate
'Cin'.
For 'Ron' for the of driver, you need to calculate 'Ron-pullup' and
'Ron-pulldown' seperately. For 'Ron-pulldown' apply i/p to your driver
to ON pulldown path of your driver and OFF completely pullup path. Apply
output Low voltage 'Vol' at the output of your driver. Check your
current from 'Vol' and calculate 'Ron-pulldown' by simple R=V/I. Check
SSTL JEDEC std. which has spread sheets showing 'Ron' for SSTL drivers.
This works for low values of 'Vol'. To get more exact, plot V-I curve of
your pulldown path and check the slope at 'Vol'.
But one confusion i am having is, what should be my 'Vol'. We will get
different values of 'Ron' for different values of 'Vol', unless we have
an ohmic driver.
Take an example of 2.5V CMOS output buffer. For what 'Vol' should I
specify my 'Ron-pulldown':
1) At 'Volmax' specified 2.5V CMOS output buffer.
2) At 'VDD/2' where VDD is o/p buf. supply voltage.
3) Or should i just give the output V-I characteristics and let the user
to find his value of 'Ron' from it.
I would appriciate comments from experts.
Thanks
Rajat
>
> Hi
>
> If I have a minimum size inverter as both driver and receiver, then
> how should I proceed calculating the on resistance of the driver and
> the input capacitance of the receiver for 0.13um technology.
>
> Can you provide the detail documentation on this?
>
> Thanks
> Haritha
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
> or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
> Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
--
___________________________
RAJAT CHAUHAN
TI-Banglore
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
