74HC3G14 Datasheet, PDF (16/20 Pages) NXP Semiconductors – Inverting Schmitt-triggers

Philips Semiconductors
Inverting Schmitt-triggers
Product specification
74HC3G14; 74HCT3G14
APPLICATION INFORMATION
Power dissipation
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_CC(AV) + t_f × I_CC(AV)) × V_CC
Where:
P_ad = additional power dissipation (µW)
f_i = input frequency (MHz)
t_r = input rise time between 10% and 90% (ns);
t_f = input fall time between 90% and 10% (ns);
I_CC(AV) = average additional supply current (µA).
Average I_CC(AV) differs with positive or negative input
transitions, as shown in Fig.14 and Fig.15.
Relaxation oscillator
A relaxation oscillator circuit using the HC3G14/HCT3G14
is shown in Fig.16.
Remark to the application information
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)
Linear change of V_I between 0.1V_CC to 0.9V_CC.
Fig.14 Average I_CC for HC Schmitt-trigger devices.
handboo²k,⁰h⁰alfpage
ICC(AV)
(µA)
150
100
MNA058
positive-going
edge
50
negative-going
edge
0
0
2
4 _{VCC (V)} 6
Linear change of V_I between 0.1V_CC to 0.9V_CC.
Fig.15 Average I_CC for HCT Schmitt-trigger
devices.
2003 Nov 04
handbook, halfpage
R
C
MNA035
For HC3G: f = _T-1-- ≈ _{0----.-8-----×}-1----R-----C---
For HCT3G: f = _T-1-- ≈ _{0----.-6----7---1--×}----R-----C---
Fig.16 Relaxation oscillator using the
HC3G/HCT3G14.
16