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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 Congurations
● 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
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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: 781.329.4700 | © 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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ICM7555/ICM7556 General-Purpose Timers
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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