Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Ludwig, T: AUTHOR [+2]
This article describes a latching receiver which stores the last active input value of a tristate net.
describes a latching receiver which stores
the last active input value of a tristate net.
This value is
fed back to the net and the receiver output.
receiver also serves as a high-impedance driver, and no DC current is
required for holding the input value at a CMOS tristate net. An
external change current is required to compensate for the latch
holding current before the complement logic state is stored. If the
net is in a tristate mode, the latching receiver avoids a net drift
into another logic state depending upon environmental conditions. The
receiver has a high noise immunity in both logic states and allows
testing a net which is not accessible by pads. The described circuit
replaces chip external terminators, thus reducing the cost of the
shows the latching receiver circuit comprising a
connection of the gate of transistor 3 to the gate of transistor 2.
It is also possible to connect the gate of transistor 3 to the gate
of transistor 1. Transistor 2 serves as an electrostatic discharge
protection means if the potential at D10 is higher than VH and
transistors 1 and 3 are used for test purposes only. The preload
input PRL, connected to the gate of transistor 1, is negatively
active during the testing of a tristate mode net.
operation, transistors 5 and 6 or 4 and 7 latch the
state of receiver input RA0. This avoids an undefined internal logic