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Tri-State Driver With Integrated Hold Circuit

IP.com Disclosure Number: IPCOM000100228D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Haug, W: AUTHOR [+4]

Abstract

An on-module driver/receiver scheme is proposed in which the hold circuit of the "latched" receiver is removed and integrated with a tri- state driver (TSD), thus providing a high-speed receiver.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Tri-State Driver With Integrated Hold Circuit

       An on-module driver/receiver scheme is proposed in which
the hold circuit of the "latched" receiver is removed and integrated
with a tri- state driver (TSD), thus providing a high-speed receiver.

      In state of the art structures, chip-to-chip signals are
transmitted via TSDs and receivers.  The TSDs switch from on (up- or
down- level) to off (high impedance state/HZ).  If the output of the
TSD floats, leakage current may cause the receiver input to drift to
any voltage level. If the gate input of CMOS receivers remains near
1/2 VH (power supply voltage VH), the P- and N-FETs of the input
inverter draw current.  Power dissipation and noise become
intolerable with, e.g., 80 bus lines and more.

      A latched receiver is presently used.  This receiver holds its
input levels for HZ at an up- or down-level.  The latched receiver
has a high noise tolerance (hysteresis).

      An on-module driver/receiver has a higher speed (dedicated
design) than an off-module driver/receiver. Proposed is a
high-performance driver/receiver scheme.  The input hold latch is
removed.  The layout of the hold function, achieved by a latch in
Fig. 1 comprising FETs T1 to T4, is integrated in the TSD.  The
performance of the receiver is not reduced by the latch delay stage
(no hysteresis).  A lower noise tolerance is compensated for by
higher speed and is tolerable with chip-to-chip (chips on a common
module substrate...