Datasheet ICM7242 Datasheet (Intersil Corporation)

ICM7242

November 1996

Features

• Replaces the 2242 in Most Applications

• Timing From Microseconds to Days

• Cascadable

• Monostable or Astable Operation

• Wide Supply Voltage Range . . . . . . . . . . . . . . 2V to 16V

• Low Supply Current. . . . . . . . . . . . . . . . . . . 115µA at 5V

Ordering Information

PART NUMBER

(BRAND)

ICM7242IPA -25 to 85 8 Ld PDIP E8.3
ICM7242CBA

(7242CBA)

TEMP.

RANGE (oC) PACKAGE

0 to 70 8 Ld SOIC M8.15

PKG.

NO.

Long Range Fixed Timer

Description

The ICM7242 is a CMOS timer/counter circuit consisting of
an RC oscillator followed by an 8-bit binary counter. It will
replace the 2242 in most applications, with a significant
reduction in the number of external components.

Three outputs are provided. They are the oscillator output,
and buffered outputs from the first and eighth counters.

Pinout

ICM7242

(PDIP, SOIC)

TOP VIEW

V

DD

÷2 OUT

÷128/256 OUT

V

SS

1
2
3
4

8

TB I/O

7

RC

6

TRIGGER

5

RESET

Functional Diagram

R

1

50K

+

R

2

86K

7

R

3

RC

50K

1 4 8 5 6 2 3

V

DD

-

+

-

V

SS

R

Q

S

Q

R

CL

Q

Q

S

CL

CL

Q

Q

S

Q

Q

S

CL

CL

Q

Q

S

Q

Q

S

Q

CL

Q

S

Q

CL

Q

S

TRIGGERRESET ÷2 OUTTB I/O

CL

S

Q

Q

÷128/256

OUTPUT

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143 | Copyright © Intersil Corporation 1999

8-163

File Number 2866.2

ICM7242

Absolute Maximum Ratings Thermal Information

Supply Voltage (VDD to VSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . 18V

Input Voltage (Note 1)

Terminals (Pins 5, 6, 7, 8). . . . . . . . . .(VSS -0.3V) to (VDD +0.3V)

Continuous Output Current (Each Output). . . . . . . . . . . . . . . .50mA

Operating Conditions

Temperature Range

ICM7242I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25oC to 85oC

ICM7242C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0oC to 70oC

CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation
of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.

NOTES:

1. Due to the SCR structure inherent in the CMOS process, connecting any terminal to voltages greater than VDD or less than VSS may cause
destructive device latchup. For this reason, it is recommended that no inputs from external sources not operating on the same supply be
applied to the device before its supply is established and, that in m ultiple supply systems, the supply to the ICM7242 be turned on first.

2. θJA is measured with the component mounted on an evaluation PC board in free air.

Thermal Resistance (Typical, Note 2) θJA (oC/W)

PDIP Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

SOIC Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Maximum Storage Temperature Range . . . . . . . . . -65oC to 150oC

Maximum Junction Temperature (Plastic Package) . . . . . . . . 150oC

Maximum Lead Temperature (Soldering 10s). . . . . . . . . . . . . 300oC

(SOIC - Lead Tips Only)

Electrical Specifications V

= 5V, TA = 25oC, R = 10kΩ, C = 0.1µF, VSS = 0V, Unless Otherwise Specified

DD

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

Guaranteed Supply Voltage V
Supply Current I

DD

DD

Reset - 125 - µA

2 - 16 V

Operating, R = 10kΩ, C = 0.1µF - 340 800 µA
Operating, R = 1MΩ, C = 0.1µF - 220 600 µA
TB Inhibited, RC Connected to V

SS

- 225 - µA
Timing Accuracy -5-%
RC Oscillator Frequency Temperature

∆f/∆t Independent of RC Components - 250 - ppm/oC

Drift
Time Base Output Voltage V

Time Base Output Leakage Current I
Trigger Input Voltage V

OTBISOURCE

I

SINK

TBLK

TRIG

RC = Ground - - 25 µA
VDD = 5V - 1.6 2.0 V

= 100µA - 3.5 - V

= 1.0mA - 0.40 - V

VDD = 15V - 3.5 4.5 V

Reset Input Voltage V

RST

VDD = 5V - 1.3 2.0 V

VDD = 15V - 2.7 4.0 V
Trigger/Reset Input Current I
Max Count Toggle Rate f

TRIG

, I

RST

VDD = 2V

T

VDD = 5V 2 6 - MHz

Counter/Divider Mode

-10-µA

- 1 - MHz

VDD = 15V - 13 - MHz

50% Duty Cycle Input with Peak to Peak

Output Saturation Voltage V

Output Sourcing Current I

SOURCEVDD

MIN Timing Capacitor (Note 3) C
Timing Resistor Range (Note 3) R

SAT

T
T

Voltages Equal to VDD and V

All Outputs Except TB Output VDD = 5V,

I

= 3.2mA

OUT

= 5V Terminals 2 and 3, V

VDD = 2 - 16V 1K - 22M Ω

SS

- 0.22 0.4 V

= 1V - 300 - µA

OUT

10 - - pF

NOTE:

3. For design only, not tested.

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Test Circuit

1

÷2

(RC/2) OUTPUT

8

÷2

(RC/256) OUTPUT

ICM7242

V

DD

1
2
3
4

TIME BASE INPUT/OUTPUT

8
7
6
5

C

V

R

DD

NOTE:

4. ÷21 and ÷28 outputs are inverters and have active pullups.

Application Information

Operating Considerations

Shorting the RC terminal or output terminals to V
exceed dissipation ratings and/or maximum DC current limits
(especially at high supply voltages).

There is a limitation of 50pF maximum loading on the TB I/O
terminal if the timebase is being used to drive the counter
section. If higher value loading is used, the counter sections
may miscount.

For greatest accuracy, use timing component values shown
in Figure 8. For highest frequency operation it will be desir­able to use very low values for the capacitor; accuracy will
decrease for oscillator frequencies in excess of 200kHz.

The timing capacitor should be connected between the RC
pin and the positive supply rail, V

, as shown in Figure 1.

DD

When system power is turned off, any charge remaining on
the capacitor will be discharged to ground through a large
internal diode between the RC node and V

. Do NOT refer-

SS

ence the timing capacitor to ground, since there is no high
current path in this direction to safely discharge the capacitor
when power is turned off. The discharge current from such a
configuration could potentially damage the device.

When driving the counter section from an external clock, the
optimum drive waveform is a square wave with an amplitude
equal to the supply voltage. If the clock is a very slow ramp
triangular, sine wave, etc., it will be necessary to “square up”
the waveform; this can be done by using two CMOS invert­ers in series, operating from the same supply voltage as the
ICM7242.

The ICM7242 is a non-programmable timer whose principal
applications will be very low frequency oscillators and long
range timers; it makes a much better low frequency oscilla­tor/timer than a 555 or ICM7555, because of the on-chip
8-bit counter. Also, devices can be cascaded to produce
extremely low frequency signals.

DD

may

TRIGGERRESET

TIME BASE PERIOD = 1.0RC;
1s = 1MΩ x 1µF

The timing diagram for the ICM7242 is shown in Figure 1.
Assuming that the device is in the RESET mode, which
occurs on power up or after a positive signal on the RESET
terminal (if TRIGGER is low), a positive edge on the trigger
input signal will initiate normal operation. The discharge
transistor turns on, discharging the timing capacitor C, and
all the flip-flops in the counter chain change states. Thus, the
outputs on terminals 2 and 3 change from high to low states.
After 128 negative timebase edges, the ÷2

8

output returns to

the high state.

TRIGGER INPUT
(TERMINAL 6)

TIMEBASE INPUT
(TERMINAL 8)

÷2 OUTPUT

(TERMINAL 2)

÷128/256 OUTPUT

(TERMINAL 3) (ASTABLE

128RC 128RC

128RC

FIGURE 1. TIMING DIAGRAMS OF OUTPUT WAVEFORMS

FOR THE ICM7242 (COMPARE WITH FIGURE 5)

V

DD

1

f

IN/2

OUTPUTS

f

IN/256

2
3
4

OR “FREE RUN” MODE)

÷128/256 OUTPUT

(TERMINAL 3)
(MONOSTABLE
OR “ONE SHOT” MODE)

f

IN

8
7
6

V

DD

5

≥3/4 (V+)
≤1/4 (V+)

Because outputs will not be ANDed, output inverters are
used instead of open drain N-Channel transistors, and the
external resistors used for the 2242 will not be required for
the ICM7242. The ICM7242 will, however, plug into a socket
for the 2242 having these resistors.

FIGURE 2. USING THE ICM7242 AS A RIPPLE COUNTER

(DIVIDER)

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ICM7242

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 cas­caded (see Figure 3).

V

DD

1
2
3
4

R

8
7
6
5

C

f = RC/2

1
2

ICM7242ICM7242

3
4

16

8
7
6
5

FIGURE 3. LOW FREQUENCY REFERENCE (OSCILLATOR)

For monostable operation the ÷2

8

output is connected to the
RESET terminal. A positive edge on TRIGGER initiates the
cycle (NOTE: TRIGGER overrides RESET).

V

DD

OUTPUT

1
2
3
4

ICM7242

8
7
6
5

100kΩ

S

1

RESET

R

C

TRIGGER

Comparing the ICM7242 With the 2242

ICM7242 2242

Operating Voltage 2V - 16V 4V - 15V
Operating Temperature Range -25oC to 85oC0oC to 70oC
Supply Current, VDD = 5V 0.7mA (Max) 7mA (Max)
Pullup Resistors

TB Output No Yes

÷2 Output No Yes
÷256 Output No Yes

Toggle Rate 3.0MHz 0.5MHz
Resistor to Inhibit Oscillator No Yes
Resistor in Series with Reset for

No Yes

Monostable Operation
Capacitor TB Terminal for HF

No Sometimes

Operation

By selection of R and C, a wide variety of sequence timing
can be realized. A typical flow chart for a machine tool con­troller could be as shown in Figure 5.

TRIGGERING CAN BE
OBTAINED FROM A
PREVIOUS STAGE, A
LIMIT SWITCH, OPER­ATOR SWITCH, ETC.

STOP

START STOP

WAIT

ENABLE

5s

START

ENABLE

5s

ICM7242 ICM7240 ICM7242

WAIT

10s

5s

ICM7242 ICM7242

WAIT

5s

COUNT

TO 185

COUNT

TO 185

ENABLE

5s

ENABLE

10s

WAIT

5s

TRIGGER

TB OUTPUT

OUTPUT TERMINAL 3

TERMINAL 6

TERMINAL 8

FIGURE 4. MONOSTABLE OPERATION

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 5. FLOW CHART FOR MACHINE TOOL CONTROLLER

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 appli­cations include injection molding machine controllers, pho­nograph record production machines, automatic sequencers
(no metal contacts or moving parts), milling machine control­lers, process timers, automatic lubrication systems, etc.

Sequence Timing

• Process Control

• Machine Automation

• Electro-Pneumatic Drivers

• Multi Operation (Serial or Parallel Controlling)

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ICM7242

TRIGGER

V

DD

S

1

PUSH S

TO START SEQUENCE:

1

TRIGGER

OUTPUT A (NOTE)

OUTPUT B (NOTE)

50K

V

DD

R (NOTE)

63

ICM7242
A

MUST BE SHORTER THAN “ON TIME

128RC

C

5

100pF

33K

A

1µF

10K

V

DD

R (NOTE)

C

63

ICM7242

B

33K

5

100pF

128RC

V

DD

B

1µF

10K

”

A

R (NOTE)

63

ICM7242
C

CD

C

5

100pF

1µF

33K

10K

V

DD

R (NOTE)

C

63

ICM7242
D

33K

5

100pF

OUTPUT C (NOTE)

OUTPUT D (NOTE)

ON TIME

A

NOTE: Select RC values for desired “ON TIME” for each ICM7242.

FIGURE 6. SEQUENCE TIMER

ON TIME

128RC

128RC

ONTIME

B

C

ON TIME

D

8-167

Typical Performance Curves

ICM7242

260
240
220
200
180
160
140
120
100

80
60

SUPPLY CURRENT (µA)

40
20

0

0 2 4 6 8 10121416

SUPPLY VOLTAGE (V)

TA = -20oC

TA = 25oC

TA = 75oC

RESET MODE

100M

10M

1M

100k

10k

TIMING RESISTOR, R (Ω)

1k

100

100pF 0.01 1 10 100 1000 10,000

RECOMMENDED RANGE OF

TIMING COMPONENT VALUES

0.10.001

TIMING CAPACITOR, C (µF)

TA = 25oC

FIGURE 7. SUPPLY CURRENT vs SUPPLY VOLTAGE FIGURE 8. RECOMMENDED RANGE OF TIMING COMPONENT

VALUES FOR ACCURATE TIMING

10,000µ

1,000µ

100µ

10µ

1µ

0.1µ

0.01µ

CAPACITANCE (F)

0.001µ

100p

10p

1MΩ

1p

0.1 1 10 100 1K 10K 100K 1M 10M
TIME BASE FREQUENCY (Hz)

10kΩ

100kΩ

10MΩ

VDD = 5.0V

= 25oC

T

A

1kΩ

1500
1400
1300
1200
1100
1000

900
800
700
600
500
400
300

TRIGGER PULSE WIDTH (ns)

200

VDD = 2V

100

0

012345678910

VDD = 5V

VDD = 16V

TRIGGER AMPLITUDE (V)

TA = 25oC

FIGURE 9. TIMEB ASE FREE R UNNING FREQUENCY vs R AND C FIGURE 10. MINIMUM TRIGGER PULSE WIDTH vs TRIGGER

AMPLITUDE

1500
1400
1300
1200
1100
1000

900
800
700
600
500
400

RESET PULSE WIDTH (ns)

300
200
100

0

012345678910

VDD = 5V

VDD = 2V

VDD = 16V

RESET AMPLITUDE (V)

TA = 25oC

FIGURE 11. MINIMUM RESET PULSE WIDTH vs RESET

AMPLITUDE

+10.0

+8.0
+6.0
+4.0
+2.0

0.0

-2.0

-4.0

-6.0

-8.0

-10.0

NORMALIZED FREQUENCY DEVIATION (%)

TA = 25oC

R

10kΩ
1MΩ
1kΩ
100kΩ
10kΩ
100kΩ

2 101214161820

864

SUPPLY VOLTAGE (V)

FIGURE 12. NORMALIZED FREQUENCY STABILITY IN THE

AST ABLE MODE vs SUPPLY V OLTAGE

C

0.001µF
100pF

0.1µF

0.001µF

0.01µF

0.01µF

8-168

Typical Performance Curves (Continued)

ICM7242

+5

5V ≤ VDD≤ 15V

+4
+3
+2
+1

0

-1

-2

-3

-4

NORMALIZED FREQUENCY DEVIA TION (%)

-5

-25 0 25 50 75
TEMPERATURE (oC)

R = 10MΩ

C = 0.1µF

R = 1kΩ
C = 0.1µF

FIGURE 13. NORMALIZED FREQUENCY STABILITY IN THE

AST ABLE MODE vs TEMPERATURE

100

TA = 25oC

VDD = 15V

VDD = 5V

10

100M

10M

1M

100K

MAXIMUM DIVIDER FREQUENCY (Hz)

10K

0

2 101214161820

864

SUPPLY VOLTAGE (V)

TA = 25oC
RC CONNECTED

TO GROUND

FIGURE 14. MAXIMUM DIVIDER FREQUENCY vs SUPPLY

VOLTAGE

100

TA = 25oC

10

VDD = 15V

VDD = 5V

VDD = 2V

1

DISCHARGE SINK CURRENT (mA)

0.1

0.01 0.1 1 10
DISCHARGE SATURATION VOLTAGE (V)

FIGURE 15. DISCHARGE OUTPUT CURRENT vs DISCHARGE

OUTPUT VOLTAGE

VDD = 2V

1

OUTPUT SATURATION CURRENT (mA)

0.1

0.01 0.1 1 10
OUTPUT SATURATION VOLTAGE (V)

FIGURE 16. OUTPUT SATURATION CURRENT vs OUTPUT

SATURATION VOLTAGE

8-169