Philips Semiconductors
Inverting Schmitt-triggers
Product specification
74HC1G14; 74HCT1G14
APPLICATION INFORMATION
The slow input rise and fall times cause additional power
dissipation, this can be calculated using the following
formula:
Pad = fi × (tr × ICCa + tf × ICCa) × VCC
Where:
Pad = additional power dissipation (µW)
fi = input frequency (MHz)
tr = input rise time (ns); 10% to 90%
tf = input fall time (ns); 90% to 10%
ICCa = average additional supply current (µA).
Average ICCa differs with positive or negative input
transitions, as shown in Fig.14 and Fig.15.
HC1G/HCT1G14 used in relaxation oscillator circuit,
see Fig.14 and Fig.16.
Note to the application information:
1. All values given are typical unless otherwise specified.
handboo2k,0h0alfpage
ICC(AV)
(µA)
150
100
MNA036
positive-going
edge
50
negative-going
edge
0
0
2.0
4.0
6.0
VCC (V)
Fig.14 Average ICC for HC1G Schmitt-trigger
devices; linear change of VI between
0.1VCC to 0.9VCC.
handboo2k,0h0alfpage
ICC(AV)
(µA)
150
100
50
0
0
2
MNA058
positive-going
edge
negative-going
edge
4 VCC (V) 6
Fig.15 Average ICC for HCT1G Schmitt-trigger
devices; linear change of VI between
0.1VCC to 0.9VCC.
2002 May 15
handbook, halfpage
R
C
MNA035
For HC1G: f = T-1-- ≈ 0----.-8-----×-1----R-----C---
For HCT1G: f = T-1-- ≈ 0----.-6----7---1--×----R-----C---
Fig.16 Relaxation oscillator using the
HC1G/HCT1G14.
11