MAXIM ICM7556IPD+ Datasheet

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General-Purpose Timers

General Description

The Maxim ICM7555 and ICM7556 are respectively sin­gle and dual general-purpose RC timers capable of gen­erating accurate time delays or frequencies. The primary
feature is an extremely low supply current, making this
device ideal for battery-powered systems. Additional fea­tures include low THRESHOLD, TRIGGER, and RESET
currents, a wide operating supply voltage range, and
improved performance at high frequencies.

These CMOS low-power devices offer significant perfor­mance advantages over the standard 555 and 556 bipolar
timers. Low-power consumption, combined with the virtually
nonexistent current spike during output transitions, make
these timers the optimal solution in many applications.

Applications

● Pulse Generator

● Precision Timing

● Time Delay Generation

● Pulse-Width Modulation

Pin Congurations

● Pulse Position Modulation

● Sequential Timing

● Missing Pulse Detector

ICM7555/ICM7556

Features

● Improved 2nd Source (See 4th Page for Maxim

Advantage)

● Wide Supply Voltage Range: 2V to 18V

● No Crowbarring of Supply During Output Transition

● Adjustable Duty Cycle

● Low THRESHOLD, TRIGGER, and RESET Currents

● TTL Compatible

● Monolithic, Low-Power CMOS Design

Ordering Information

PART TEMP RANGE PIN-PACKAGE

ICM7555ESA -40°C to +85°C 8 SO

ICM7555IPA -20°C to +85°C 8 PDIP

ICM7555ISA -20°C to +85°C 8 SO

ICM7555MJA/HR -55°C to +125°C 8 CERDIP

ICM7555/D 0°C to +70°C Dice

ICM7556IPD -20°C to +85°C 14 PDIP

ICM7556ISD -20°C to +85°C 14 SO

ICM7556MJD -55°C to +125°C 14 CERDIP

ICM7556/D 0°C to +70°C Dice

Typical Operating Circuit

19-0481; Rev 3; 3/13

©

2013 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners.

One Analog Way, Wilmington, MA 01887 U.S.A. | Tel: [phone] | © 2013 Analog Devices, Inc. All rights reserved.

ICM7555/ICM7556 General-Purpose Timers

Absolute Maximum Ratings

Supply Voltage ...................................................................+18V

Input Voltage TRIGGER

Control Voltage THRESHOLD ..............< V+ +0.3V to ≥ -0.3V

RESET

Output Current ..................................................................100mA

Power Dissipation (Note 2)

ICM7556 ......................................................................300mW

ICM7555 ......................................................................200mW

Operating Temperature Range

ICM75551JA (Maxim) ..................................... -20°C to +85°C

Note 1: Due to the SCR structure inherent in the CMOS process used to fabricate these devices, connecting any terminal to a volt-

age greater than V+ + 0.3V or less than V- - 0.3V may cause destructive latchup. For this reason it is recommended that no

inputs from external sources not operating from the same power supply be applied to the device before its power supply is
established in multiple systems. The supply of the ICM7555/ICM7556 must be turned on first.

Note 2: Junction temperatures should not exceed 135°C and the power dissipation must be limited to 20mW at +125°C. Below

125°C, power dissipation may be increased to 300mW at 25°C. Derating factor is approximately 3mW/°C (ICM7556) or
2mW/°C (ICM7555).

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these
or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.

(Note 1)

ICM75551SA (Maxim) ................................... -20°C to +85°C

ICM75551PA ................................................... -20°C to +85°C

ICM75551TV................................................... -20°C to +85°C

ICM75561PD .................................................. -20°C to +85°C

ICM7555MTV................................................ -55°C to +125°C

ICM7556MJD ................................................ -55°C to +125°C

Storage Temperature ........................................ -65°C to +150°C

Lead Temperature (soldering, 60s) .................................+300°C

Electrical Characteristics

(V+ = +2V to +15V; TA = +25°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage V+

Supply Current (Note 3) I+

Timing Error

Initial Accuracy (Note 4) 2.0 5.0 %

Drift with Temperature (Note 4)

Drift with Supply Voltage V+ = 5V 1.0 3.0 %/V

Threshold Voltage V

Trigger Voltage V

Trigger Current I

Threshold Current I

TH

TRIG

TRIG

TH

-20°C ≤ TA ≤ +70° 2 18

-55°C ≤ TA ≤ +125° 3 16

ICM7555

ICM7556

RA, RB = 1kΩ to

100kΩ, C = 0.1µF

V+ = 5V 0.63 0.66 0.67 V+

V+ = 5V 0.29 0.33 0.34 V+

V+ = 18V 50

V+ = 2V 1

V+ = 18V 50

V+ = 5V 10

V+ = 2V 1

V+ = 2V 60 200

V+ = 18V 120 300

V+ = 2V 120 400

V+ = 18V 240 600

5V ≤ V+ ≤ 15V

V+ = 5V 50

V+ = 10V 75

V+ = 15V 100

V

µA

ppm/°C

pAV+ = 5V 10

pA

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Electrical Characteristics (continued)

(V+ = +2V to +15V; TA = +25°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V+ = 18V 100

Reset Current I

Reset Voltage V

Control Voltage Lead V

Output Voltage Drop V

Rise Time of Output t
Fall Time of Output t

Guaranteed Max Osc.

Frequency

RST

RST

f

max

CV

O

r

f

V

REST

= Ground

pAV+ = 5V 20

V+ = 2V 2

V+ = 18V 0.4 0.7 1.0

V+ = 2V 0.4 0.7 1.0

V

V+ = 5V 0.62 0.66 0.67 V

Output Lo

Output Hi

V+ = 18V I

V+ = 5V I

V+ = 18V I

V+ = 5V I

RL = 10MΩ CL = 10pF V+ = 5V 35 40 75

RL = 10MΩ CL = 10pF V+ = 5V 35 40 75

= 3.2mA 0.1 0.4

SINK

= 3.2mA 0.15 0.4

SINK

SOURCE

SOURCE

= 1.0mA 17.25 17.8

= 1.0mA 4.0 4.5

V

ns

Astable operation 500 kHz

Note 3: The supply current value is essentially independent of the TRIGGER, THRESHOLD, and RESET voltages.
Note 4: Parameter is not 100% tested. Majority of all units meet this specification.

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ICM7555/ICM7556 General-Purpose Timers

Maxim Advantage

●

Lower Supply Current

●

Increased Output Source Current

●

Guaranteed THRESHOLD, TRIGGER, and RESET
Input Currents

Absolute Maximum Ratings

This device conforms to the Absolute Maximum Ratings on adjacent page.

Electrical Characteristics

Specifications below satisfy or exceed all “tested” parameters on adjacent page.
(V+ = +2V to +15V; TA = +25°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage V+

Supply Current
(Note 3)

Timing Error (Note 4)

Initial Accuracy (Note 5) 2.0 5.0 %

Drift with Temperature

Drift with Supply Voltage V+ = 5V 1.0 3.0 %V

Threshold Voltage V

Trigger Voltage V

Trigger Current I

Threshold Current I

Reset Current I

I+

TH

TRIG

TRIG

TH

RST

-20°C ≤ TA ≤ +85° 2 16.5

-55°C ≤ TA ≤ +125° 3 16

ICM7555

ICM7556

Circuit of Figure 1b;
RA = RB 100kΩ, C = 0.1µF, V+ = 5V

V+ = 5V 50

V+ = 15V 100

V+ = 5V 0.63 0.66 0.67 V+

V+ = 5V 0.29 0.33 0.34 V+

V+ = 16.5V 50

V+ = 5V 10

V+ = 2V 1

V+ = 16.5V 50

V+ = 5V 10

V+ = 2V 1

V

= Ground

REST

●

Guaranteed Discharge Output Voltage

●

Supply Current Guaranteed Over Temperature

●

Significantly Improved ESD Protection (Note 6)

●

Maxim Quality and Reliability

V+ = 2V to 16.5V; TA = +25°C 30 250

V+ = 5V; TA = +25°C 120

V+ = 5V; -20°C ≤ TA ≤ +85°C 250

V+ = 5V; -55°C ≤ TA ≤ +125°C 300

V+ = 2V to 16.5V; TA = +25°C 60 500

V+ = 5V; TA = +25°C 240

V+ = 5V; -20°C ≤ TA ≤ +85°C 500

V+ = 5V; -55°C ≤ TA ≤ +125°C 600

V+ = 16.5V 100

V+ = 2V 2

V

µA

µA

ppm/°CV+ = 10V 75

pA

pA

pAV+ = 5V 20

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ICM7555/ICM7556 General-Purpose Timers

Electrical Characteristics (continued)

Specifications below satisfy or exceed all “tested” parameters on adjacent page.
(V+ = +2V to +15V; TA = +25°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Reset Voltage V

Control Voltage V

Output Voltage Drop V

Discharge Output Voltage V

Rise Time of Output
(Note 4)

Fall Time of Output
(Note 4)

Guaranteed Max Osc.

Frequency (Note 4)

RST

DIS

f

max

CV

t

t

O

r

f

V+ = 16.5V 0.4 0.7 1.2

V+ = 2V 0.4 0.7 1.2

V

V+ = 5V 0.62 0.66 0.67 V+

Output Lo

Output Hi

V+ = 5V, I

V+ = 16.5V I

V+ = 5V I

V+ = 16.5V I

V+ = 5V I

= 3.2mA 0.1 0.4 V

DIS

= 3.2mA 0.1 0.4

SINK

= 3.2mA 0.15 0.4

SINK

SOURCE

SOURCE

= 2.0mA 15.75 16.25

= 2.0mA 4.0 4.5

V

RL = 10MΩ CL = 10pF V+ = 5V 35 40 75

ns

RL = 10MΩ CL = 10pF V+ = 5V 35 40 75

Astable Operation 500 kHz

Note 1: Due to tho SCR structure inherent in the CMOS process used to fabricate these devices, connecting any terminal to a volt-

age greater than V+ + 3V or less than V- - 0.3V may cause destructive latchup. For this reason it is recommended that no

inputs from external sources not operating from the same power supply be applied to the device before its power supply is
established. In multiple systems, the supply of the ICM7555/ICM7556 must be turned on first.

Note 2: Junction temperatures should not exceed 135°C and the power dissipation must be limited to 20mW at 125°C. Below

125°C, power dissipation may be increased to 300mW at 25°C. Derating factor is approximately 3mW/°C (ICM7556) or
2mW/°C (ICM7555).

Note 3: The supply current value is essentially independent of the TRIGGER, THRESHOLD, and RESET voltages.
Note 4: Parameter is not 100% tested. Majority of all units meet this specification.
Note 5: Deviation from f = 1.46/(RA + 2 RB)C. V+ = 5V.
Note 6: All pins are designed to withstand electrostatic discharge (ESD) level in excess of 2000V. (Mil Std 883B Method 3015 1

Test Circuit).

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ICM7555/ICM7556 General-Purpose Timers

Typical Operating Characteristics

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ICM7555/ICM7556 General-Purpose Timers

Typical Operating Characteristics (continued)

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1

AB

1.46

AB

R

ICM7555/ICM7556 General-Purpose Timers

Detailed Description

Both the ICM7555 timer and the ICM7556 dual timer can
be configured for either astable or monostable operation.
In the astable mode, the free-running frequency and the
duty cycle are controlled by two external resistors and
one capacitor. Similarly, the pulse width in the monostable
mode is precisely controlled by one external resistor and
capacitor.

The external component count is decreased when replac­ing a bipolar timer with the ICM7555 or ICM7556. The
bipolar devices produce large crowbar currents in the
output driver. To compensate for this spike, a capacitor
is used to decouple the power-supply lines. The CMOS
timers produce supply spikes of only 2mA to 3mA vs.
300mA to 400mA (Bipolar), therefore supply decoupling
is typically not needed. This current spike comparison is

illustrated in Figure 3. Another component is eliminated at

the control voltage pin. These CMOS timers, due to the
high-impedance inputs of the comparators, do not require
decoupling capacitors on the control voltage pin.

Figure 3. Supply Current Transient Compared With A Standard
Bipolar 555 During An Output Transition

Applications Information

Astable Operation

Maxim recommends either of the two astable circuit con-

figurations illustrated in Figure 1. The circuit in Figure 1a

provides a 50% duty-cycle output using one timing resistor
and cap acitor. The oscillator waveform across the capaci­tor is symmetrical and triangular, swinging from 1/3 to 2/3
of the supply voltage. The frequency generated is defined
by:

Figure 1. Maxim ICM7555 Used in Two Different Astable
Configurations

Figure 2. Maxim ICM7555 in Monostable Operation

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f

=

1.4 RC

The circuit in Figure 1b provides a means of varying the

duty cycle of the oscillator. The frequency is defined by:

f

=

(R 2R ) C

+

The duty cycle is:

D

=

B

(R 2R )

+

Monostable Operation

The circuit diagram in Figure 2 illustrates monostable

operation. In this mode the timer acts as a one shot.
Initially the external capacitor is held discharged by
the discharge output. Upon application of a negative
TRIGGER pulse to pin 2, the capacitor begins to charge
exponentially through RA. The device resets after the volt-

age across the capacitor reaches ⅔(V+).

t

OUTPUT

= -In(1/3)RAC = 1.1RAC

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ICM7555/ICM7556 General-Purpose Timers

Reset

The reset function is significantly improved over the
standard bipolar 555 and 556 in that it controls only the
internal flip-flop, which in turn simultaneously controls the
state of the Output and Discharge pins. This avoids the
multiple threshold problems sometimes encountered with
slow-falling edges of the bipolar devices. This input is
designed to have essentially the same trip voltage as the
standard bipolar devices (0.6V to 0.7V). At all supply volt­ages this input maintains an extremely high impedance.

Control Voltage

The control voltage regulates the two trip voltages for the
THRESHOLD and TRIGGER internal comparators. This
pin can be used for frequency modulation in the astable
mode. By varying the applied voltage to the control voltage
pin, delay times can be changed in the monostable mode.

Figure 5. Equivalent Circuit

Power-Supply Considerations

Since the
leakage currents are very low, high-impedance timing
components may be used, keeping total system supply
current at a minimum.

TRIGGER

, THRESHOLD, and Discharge

Output Drive Capability

The CMOS output stage is capable of driving most logic
families including CMOS and TTL. The ICM7555 and
ICM7556 will drive at least two standard TTL loads at a
supply voltage of 4.5V or greater. When driving CMOS,
the output swing at all supply voltage levels will equal the
supply voltage.

Function Table

RESET

Low Irrelevant Irrelevant Low On

High < 1/3 V+ Irrelevant High O󰀨

High > 1/3 V+ > 2/3 V+ Low On

High > 1/3 V+ < 2/3 V+

†

Voltage levels shown are nominal.

Note: RESET will dominate all other inputs. TRIGGER will
dominate over THRESHOLD.

TRIGGER

VOLTAGE

THRESHOLD

VOLTAGE

OUT-

PUT

As previously estab-

DISCHARGE

SWITCH

lished

Figure 4. Block Diagram of ICM7555

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ICM7555/ICM7556 General-Purpose Timers

Chip Information

PROCESS: CMOS

Package Information

For the latest package outline information and land patterns

(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.

PACKAGE

TYPE

8 PDIP P8-1 21-0043 —

8 SO S8-2 21-0041 90-0096

14 PDIP P14-3 21-0043 —

14 CERDIP J14-3 21-0045 —

14 SO S14-1 21-0041 90-0112

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

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ICM7555/ICM7556 General-Purpose Timers

Revision History

REVISION

NUMBER

0 4/88 Initial Release —

2 11/92 Revised Electrical Characteristics 3

3 3/13 Updated Ordering Information 1

REVISION

DATE

DESCRIPTION

PAGES

CHANGED

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assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that

may result from its use.Specications subject to change without notice. No license is granted by implicationor

otherwise under any patent or patent rights of Analog Devices. Trademarks andregistered trademarks are the
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