ICM7242CBA INTERSIL [Intersil Corporation], ICM7242CBA Datasheet - Page 4

• Manufacturer Part Number: ICM7242CBA
• Description: Long Range Fixed Timer
• Manufacturer: INTERSIL [Intersil Corporation]

To use the 8-bit counter without the timebase, Terminal 7
(RC) should be connected to ground and the outputs taken
from Terminals 2 and 3.
The ICM7242 may be used for a very low frequency square
wave reference. For this application the timing components
are more convenient than those that would be required by a
555 timer. For very low frequencies, devices may be cas-
caded (see Figure 3).
For monostable operation the 2
RESET terminal. A positive edge on TRIGGER initiates the
cycle (NOTE: TRIGGER overrides RESET).
The ICM7242 is superior in all respects to the 2242 except
for initial accuracy and oscillator stability. This is primarily
due to the fact that high value p- resistors have been used
on the ICM7242 to provide the comparator timing points.
FIGURE 3. LOW FREQUENCY REFERENCE (OSCILLATOR)
TB OUTPUT
TRIGGER
OUTPUT
OUTPUT
V
DD
1
2
3
4
FIGURE 4. MONOSTABLE OPERATION
ICM7242
V
DD
1
2
3
4
8
7
6
5
ICM7242
R
C
f = RC/2
8
100k
output is connected to the
1
2
3
4
8
7
6
5
16
ICM7242
S
1
RESET
TERMINAL 6
TERMINAL 8
TERMINAL 3
TRIGGER
R
8
7
6
5
C
ICM7242
8-166
Comparing the ICM7242 With the 2242
By selection of R and C, a wide variety of sequence timing
can be realized. A typical flow chart for a machine tool con-
troller could be as shown in Figure 5.
By cascading devices, use of low cost CMOS AND/OR gates
and appropriate RC delays between stages, numerous
sequential control variations can be obtained. Typical appli-
cations include injection molding machine controllers, pho-
nograph record production machines, automatic sequencers
(no metal contacts or moving parts), milling machine control-
lers, process timers, automatic lubrication systems, etc.
Sequence Timing
• Process Control
• Machine Automation
• Electro-Pneumatic Drivers
• Multi Operation (Serial or Parallel Controlling)
TRIGGERING CAN BE
OBTAINED FROM A
PREVIOUS STAGE, A
LIMIT SWITCH, OPER-
ATOR SWITCH, ETC.
FIGURE 5. FLOW CHART FOR MACHINE TOOL CONTROLLER
Operating Voltage
Operating Temperature Range
Supply Current, V
Pullup Resistors
Toggle Rate
Resistor to Inhibit Oscillator
Resistor in Series with Reset for
Monostable Operation
Capacitor TB Terminal for HF
Operation
START
TB Output
2 Output
256 Output
WAIT
5s
STOP
ENABLE
DD
10s
= 5V
ENABLE
ICM7242
START
WAIT
5s
5s
-25
0.7mA (Max)
COUNT
TO 185
ICM7242
2V - 16V
o
3.0MHz
C to 85
ICM7242
ICM7240
No
No
No
No
No
No
COUNT
TO 185
WAIT
5s
ENABLE
o
C
5s
0
Sometimes
7mA (Max)
o
STOP
ICM7242
ENABLE
ICM7242
4V - 15V
C to 70
0.5MHz
WAIT
2242
10s
Yes
Yes
Yes
Yes
Yes
5s
o
C