Datasheet ICM7242 (Intersil) - 5

link to page 5 link to page 5 ICM7242 To use the 8-bit counter without the timebase, Terminal 7
TABLE 1. COMPARING THE ICM7242 WITH THE 2242
(RC) should be connected to ground and the outputs taken
CHARACTERISTICS ICM7242 2242
from Terminals 2 and 3. Operating Voltage 2V to 16V 4V to 15V The ICM7242 may be used for a very low frequency square wave reference. For this application the timing components Operating Temperature Range -25
°
C to 85
°
C 0
°
C to 70
°
C are more convenient than those that would be required by a Supply Current, VDD = 5V 0.7mA (Max) 7mA (Max) 555 timer. For very low frequencies, devices may be cascaded (see Figure 3). Pullup Resistors
V
TB Output No Yes
DD
2 Output No Yes
1 8 R 1 8 C
256 Output No Yes
2 7 2 7 ICM7242 ICM7242
Toggle Rate 3.0MHz 0.5MHz
3 6 3 6 4 5 4 5
Resistor to Inhibit Oscillator No Yes Resistor in Series with Reset for No Yes Monostable Operation
f = RC/216
Capacitor TB Terminal for HF No Sometimes
FIGURE 3. LOW FREQUENCY REFERENCE (OSCILLATOR)
Operation For monostable operation the 28 output is connected to the By selection of R and C, a wide variety of sequence timing RESET terminal. A positive edge on TRIGGER initiates the can be realized. A typical flow chart for a machine tool cycle (NOTE: TRIGGER overrides RESET). controller could be as shown in Figure 5.
VDD ICM7242 ICM7242 TRIGGERING CAN BE OBTAINED FROM A WAIT ENABLE 1 8 R PREVIOUS STAGE, START C 5s 10s A LIMIT SWITCH, 2 7 O - PERATOR SWITCH, ETC. ICM7242 OUTPUT 3 6 TRIGGER S ENABLE COUNT WAIT 1 STOP 4 5 5s TO 185 5s RESET 100k ICM7242 ICM7240 ICM7242 START STOP WAIT ENABLE WAIT COUNT ENABLE TRIGGER TERMINAL 6 5s 10s 5s TO 185 5s FIGURE 5. FLOW CHART FOR MACHINE TOOL CONTROLLER TB OUTPUT TERMINAL 8
By cascading devices, use of low cost CMOS AND/OR gates
OUTPUT TERMINAL 3
and appropriate RC delays between stages, numerous sequential control variations can be obtained. Typical
FIGURE 4. MONOSTABLE OPERATION
applications include injection molding machine controllers, The ICM7242 is superior in all respects to the 2242 except phonograph record production machines, automatic for initial accuracy and oscillator stability. This is primarily sequencers (no metal contacts or moving parts), milling due to the fact that high value p-resistors have been used on machine controllers, process timers, automatic lubrication the ICM7242 to provide the comparator timing points. systems, etc.
Sequence Timing
• Process Control • Machine Automation • Electro-Pneumatic Drivers • Multi Operation (Serial or Parallel Controlling) FN2866 Rev 5.00 Page 5 of 11 September 14, 2015