Datasheet

TLC556, TLC556Y
DUAL LinCMOS TIMERS
SLFS047B – FEBRUARY 1984 – REVISED SEPTEMBER 1997
11
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
The preceding equations and those given earlier are similar in that a time constant is multiplied by the logarithm
of a number or function. The limit values of the logarithmic terms must be between In 2 at low frequencies and
In 3 at extremely high frequencies. For a duty cycle close to 50%, an appropriate constant for the logarithmic
terms can be substituted with good results. Duty cycles less than 50%
t
H
t
H
t
L
will require that
t
H
t
L
<1 and
possibly R
A
≤ r
on
. These conditions can be difficult to obtain.
In monostable applications, the trip point of the trigger input can be set by a voltage applied to CONT. An input
voltage between 10% and 80% of the supply voltage from a resistor divider with at least 500-µA bias provides
good results.