Philips Semiconductors
Product specification
Quad 2-input NAND Schmitt trigger
Application information
74HC/HCT132
The slow input rise and fall times cause additional power dissipation, this can be calculated using the following formula:
P
ad
= f
i
×
(t
r
×
I
CCa
+
t
f
×
I
CCa
)
×
V
CC
.
Where:
P
ad
f
i
t
r
t
f
I
CCa
= additional power dissipation (µW)
= input frequency (MHz)
= input rise time (ns); 10%
−
90%
= input fall time (ns); 10%
−
90%
= average additional supply current (µA)
Average I
CCa
differs with positive or negative input transitions, as shown in Figs 14 and 15.
Fig.14 Average I
CC
for HC Schmitt trigger devices;
linear change of V
i
between 0.1 V
CC
to
0.9 V
CC
.
Fig.15 Average I
CC
for HCT Schmitt trigger
devices; linear change of V
i
between
0.1 V
CC
to 0.9 V
CC
.
HC/HCT132 used in a relaxation oscillator circuit, see Fig.16.
HC:
1
1
f
=
--
≈
-----------------
-
T 0.8RC
1
1
f
=
--
≈
---------------------
-
-
T 0.67 RC
HCT:
Fig.16 Relaxation oscillator using HC/HCT132.
Note to Application information
All values given are typical unless otherwise specified.
PACKAGE OUTLINES
See
“74HC/HCT/HCU/HCMOS Logic Package Outlines”.
September 1993
8
PHILIPS [ NXP SEMICONDUCTORS ]
