TECHNICAL DATA
IW4541B
Programmable Timer
High-Performance Silicon-Gate CMOS
The IW4541 programmable timer consists of a 16-stage binary
counter, an oscillator that is controlled by external R-C components (2
resistors and a capacitor), an automatic power-on reset circuit, and
output control logic. The counter increments on positive-edge clock
transitons and can also be reset via the MASTER RESET input.
The output from this timer is the Q or not Q output from the 8th,
10th, 13th, or 16th counter stage. The desired stage is chosen using
time-select inputs A and B. The output is available in either of two
modes selectable via the MODE input, pin 10. When this MODE input
is a logic 鈥?鈥?the output will be a continuous square wave having a
ORDERING INFORMATION
frequency equal to the oscillator frequency divided by 2
N
. With the
IW4541BN Plastic
MODE input set to logic 鈥?鈥?and after a MASTER RESET is initiated,
IW4541BD SOIC
the output (assuming Q output has been selected) changes from a low
N-1
to a high state after 2 counts and remains in that state until another
T
A
= -55掳 to 125掳 C for all packages
MASTER RESET pulse is applied or the MODE input is set to a logic
鈥?鈥?
Timing is initialized by setting the AUTO RESET input (pin 5) to logic 鈥?鈥漚nd turning power on. If pin 5 is
set to logic 鈥?鈥? the AUTO RESET circuit is disabled and counting will not start untill after a positive MASTER
RESET pulse is applied and returns to a low level. The AUTO RESET consumes an appreciable amount of
power and should not be used if low-power operation is desired. For reliable automatic power-on reset, V
CC
should be greater than 5V.
鈥?/div>
Operating Voltage Range: 3.0 to 18 V
鈥?/div>
Maximum input current of 1
碌A
at 18 V over full package-temperature range; 100 nA at 18 V and 25掳C
鈥?/div>
Noise margin (over full package temperature range):
1.0 V min @ 5.0 V supply
2.0 V min @ 10.0 V supply
2.5 V min @ 15.0 V supply
LOGIC DIAGRAM
PIN ASSIGNMENT
NC = NO CONNECTION
PIN 14 =V
CC
PIN 7 = GND
PINS 4,11 = NO CONNECTION
173
1
2
3
4
5
