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Browse Prior Art Database

CMOS Feedthru Driver

IP.com Disclosure Number: IPCOM000116504D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Cao, TA: AUTHOR [+6]

Abstract

Aggressive use of CMOS technology and in particular the use of large chip sizes dramatically emphasizes the problem of wire RC delay. Advanced CMOS calls for narrower line widths than was previously used leading to larger per unit length resistance. In addition the use of larger chip sizes has allowed if not encouraged the use of longer wire lengths, at least in the I/O area where signals enter and leave the chip.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

CMOS Feedthru Driver

      Aggressive use of CMOS technology and in particular the use of
large chip sizes dramatically emphasizes the problem of wire RC
delay.  Advanced CMOS calls for narrower line widths than was
previously used leading to larger per unit length resistance.  In
addition the use of larger chip sizes has allowed if not encouraged
the use of longer wire lengths, at least in the I/O area where
signals enter and leave the chip.

      The combined affect is a dramatic increase in the delay time
constant of the metal wire on the chip, know as the "RC delay".  This
was shown to be particularly pronounced in the I/O area as a result
of the constraint that the OCD placement is driven by the
availability of a C4 I/O pad.  More specifically, the delay was
encountered on the wire between the output latch and the OCD.

      This disclosure eliminates the latch to OCD RC delay line
problem by inserting the latch function into the off-chip-driver
circuit.  However, there is an important enhancement in this
disclosure.  The improvement here is that the latching function is
inserted into the off chip driver in such a way that there is
essentially no delay penalty within the off chip driver by the
addition of the latching function.  This is where the name "CMOS
FEEDTHRU DRIVER" was derived.

      The circuit takes Self-Resetting (SR) dynamic logic signals
(pulses) and converts them to DC stable signals at the driver output.
There are two sources o...