3
SuperLite
SY55852U
Micrel, Inc.
M9999-060407
hbwhelp@micrel.com or (408) 955-1690
FUNCTIONAL DESCRIPTION
VCC
NC
X
/X
Figure 1. Hard Wiring a Logic “1” (1)
Note 1.
X is either D, CLK, R input. /X is either /D, /CLK, /R input.
NC
VCC > 3.0V
NC
X
/X
NC
VCC ≤ 3.0V
X
/X
VCC
Figure 2. Hard Wiring a Logic “0” (1)
Establishing Static Logic Inputs
The true pin of an input pair is internally biased to ground
through a 75k
resistor. The complement pin of an input
pair is internally biased halfway between V
CC and ground
by a voltage divider consisting of two 75k
resistors. To
keep an input at static logic zero at V
CC > 3.0V, leave both
inputs unconnected. For V
CC ≤ 3.0V, connect the
complement inputs to V
CC and leave the true inputs
unconnected. To make an input static logic one, connect
the true input to V
CC, leave the complement input
unconnected. These are the only safe ways to cause inputs
to be at a static value. In particular, no input pin should be
directly connected to ground.
All NC (no connect) pins
should be unconnected.