HCF4541 STMicroelectronics, HCF4541 Datasheet - Page 2

• Manufacturer Part Number: HCF4541
• Description: PROGRAMMABLE TIMER
• Manufacturer: STMicroelectronics

RC Oscillator Circuit.
FUNCTIONAL DIAGRAM
HCC/HCF4541B
a logic ” 1 ”, when it is a logic ” 0 ” and after a MAS-
TER RESET is started, and Q output has been se-
lected, the output goes up to a high state after 2
counts. It remains in that state till another MASTER
RESET pulse is apply or the mode input is a logic ”
1 ”. The process starts by setting the AUTO RESET
input (pin 5) to logic ” 0 ” and switching power on. If
pin 5 is set to logic ” 1 ”, the AUTO RESET circuit is
not enabled and counting cannot start till a positive
MASTER RESET pulse is applied, returning to a low
level. The AUTO RESET consumes a remarkable
2/11
N-1
amount of power and should not be used if low-
power operation is wanted.
The frequency of the oscillator depends on the RC
network. It can be calculated using the following for-
mula:
where f is between 1 kHz and 100 kHz
and RS 10 k and
f
2.3 R
2 R
1
TC
TC
C
TC