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 used to fabricate these devices, connecting any terminal to a voltage 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 sourc-
es not operating from the same power supply be applied to the device before its power supply is established. In multiple supply systems,
the supply of the ICM7555/6 must be turned on first.
2.
θ
JA
is measured with the component mounted on an evaluation PC board in free air.
Electrical Specifications
Applies to ICM7555 and ICM7556, Unless Otherwise Specified
T
A
= 25
o
C
-55
o
C TO 125
o
C
MIN
-
-
-
-
-
858
-
-
-
-
-
1717
-
-
-
-
61
27
-
-
61
0.2
-
TYP
-
-
-
-
-
-
150
200
250
0.5
-
-
150
200
250
0.5
-
-
-
-
-
-
-
MAX
300
300
600
600
-
1161
-
-
-
-
-
2323
-
-
-
-
72
37
50
50
72
1.2
50
UNITS
µA
µA
µA
µA
%
µs
ppm/
o
C
ppm/
o
C
ppm/
o
C
%/V
%
µs
ppm/
o
C
ppm/
o
C
ppm/
o
C
%/V
% V
DD
% V
DD
nA
nA
% V
DD
V
nA
(NOTE 4)
PARAMETER
Static Supply Current
SYMBOL
I
DD
TEST CONDITIONS
ICM7555 V
DD
= 5V
V
DD
= 15V
ICM7556 V
DD
= 5V
V
DD
= 15V
MIN
-
-
-
-
-
-
TYP
40
60
80
120
2
-
-
-
-
0.5
2
-
-
-
-
0.5
67
32
-
-
67
-
-
MAX
200
300
400
600
-
-
-
-
-
-
-
-
-
-
-
-
71
36
10
10
71
1.0
10
Monostable Timing Accuracy
R
A
= 10K, C = 0.1µF, V
DD
= 5V
Drift with Temperature
(Note 3)
V
DD
= 5V
V
DD
= 10V
V
DD
= 15V
-
-
-
-
-
-
Drift with Supply (Note 3)
Astable Timing Accuracy
V
DD
= 5V to 15V
R
A
= R
B
= 10K, C = 0.1µF, V
DD
= 5V
Drift with Temperature
(Note 3)
V
DD
= 5V
V
DD
= 10V
V
DD
= 15V
-
-
-
-
62
28
-
-
62
0.4
-
Drift with Supply (Note 3)
Threshold Voltage
Trigger Voltage
Trigger Current
Threshold Current
Control Voltage
Reset Voltage
Reset Current
V
TH
V
TRIG
I
TRIG
I
TH
V
CV
V
RST
I
RST
V
DD
= 5V to 15V
V
DD
= 15V
V
DD
= 15V
V
DD
= 15V
V
DD
= 15V
V
DD
= 15V
V
DD
= 2V to 15V
V
DD
= 15V
8-171
ICM7555, ICM7556
Electrical Specifications
Applies to ICM7555 and ICM7556, Unless Otherwise Specified
T
A
= 25
o
C
PARAMETER
Discharge Leakage
Output Voltage
SYMBOL
I
DIS
V
OL
TEST CONDITIONS
V
DD
= 15V
V
DD
= 15V, I
SINK
= 20mA
V
DD
= 5V, I
SINK
= 3.2mA
V
OH
V
DD
= 15V, I
SOURCE
= 0.8mA
V
DD
= 5V, I
SOURCE
= 0.8mA
Discharge Output Voltage
V
DIS
V
DD
= 5V, I
SINK
= 15mA
V
DD
= 15V, I
SINK
= 15mA
Supply Voltage (Note 3)
Output Rise Time (Note 3)
Output Fall Time (Note 3)
Oscillator Frequency
(Note 3)
V
DD
t
R
t
F
f
MAX
Functional Operation
R
L
= 10M, C
L
= 10pF, V
DD
= 5V
R
L
= 10M, C
L
= 10pF, V
DD
= 5V
V
DD
= 5V, R
A
= 470Ω, R
B
= 270Ω,
C = 200pF
MIN
-
-
-
14.3
4.0
-
-
2.0
-
-
-
TYP
-
0.4
0.2
14.6
4.3
0.2
-
-
75
75
1
MAX
10
1.0
0.4
-
-
0.4
-
18.0
-
-
-
-55
o
C TO 125
o
C
MIN
-
-
-
14.2
3.8
-
-
3.0
-
-
-
TYP
-
-
-
-
-
-
-
-
-
-
-
MAX
50
1.25
0.5
-
-
0.6
0.4
16.0
-
-
-
UNITS
nA
V
V
V
V
V
V
V
ns
ns
MHz
(NOTE 4)
NOTES:
3. These parameters are based upon characterization data and are not tested.
4. Applies only to military temperature range product (M suffix).
Functional Diagram
V
DD
8
R
THRESHOLD
6
5
CONTROL
VOLTAGE
R
+
TRIGGER
2
R
1
COMPARATOR
A
+
4
FLIP-FLOP
RESET
OUTPUT
DRIVERS
OUTPUT
-
7
n
3
DISCHARGE
-
COMPARATOR
B
1
GND
NOTE: This functional diagram reduces the circuitry down to its simplest equivalent components. Tie down unused inputs. R = 100k
±20%
(Typ)
Ω,
TRUTH TABLE
THRESHOLD VOLTAGE
Don’t Care
>
2
/
3
(V+)
<
2
/
3
(V+)
Don’t Care
TRIGGER VOLTAGE
Don’t Care
>
1
/
3
(V+)
>
1
/
3
(V+)
<
1
/
3
(V+)
RESET
Low
High
High
High
OUTPUT
Low
Low
Stable
High
DISCHARGE SWITCH
On
On
Stable
Off
NOTE: RESET will dominate all other inputs: TRIGGER will dominate over THRESHOLD.
8-172
ICM7555, ICM7556
Schematic Diagram
V
DD
P
P
R
P
P
THRESHOLD
N
CONTROL
VOLTAGE
N
R
OUTPUT
P
TRIGGER
P
NPN
R
N
N
N
N
N
N
N
GND
RESET
R = 100kΩ
±20%
(TYP)
DISCHARGE
Application Information
General
SUPPLY CURRENT (mA)
500
T
A
= 25
o
C
400
The ICM7555/6 devices are, in most instances, direct
replacements for the NE/SE 555/6 devices. However, it is
possible to effect economies in the external component
count using the ICM7555/6. Because the bipolar 555/6
devices produce large crowbar currents in the output driver,
it is necessary to decouple the power supply lines with a
good capacitor close to the device. The 7555/6 devices pro-
duce no such transients. See Figure 1.
The ICM7555/6 produces supply current spikes of only
2mA - 3mA instead of 300mA - 400mA and supply decou-
pling is normally not necessary. Also, in most instances, the
CONTROL VOLTAGE decoupling capacitors are not
required since the input impedance of the CMOS compara-
tors on chip are very high. Thus, for many applications 2
capacitors can be saved using an ICM7555, and 3 capaci-
tors with an ICM7556.
300
SE/NE555
200
100
0
ICM7555/56
0
200
400
TIME (ns)
600
800
FIGURE 1. SUPPLY CURRENT TRANSIENT COMPARED WITH
A STANDARD BIPOLAR 555 DURING AN OUTPUT
TRANSITION
8-173
ICM7555, ICM7556
Power Supply Considerations
Although the supply current consumed by the ICM7555/6
devices is very low, the total system supply current can be
high unless the timing components are high impedance.
Therefore, use high values for R and low values for C in Fig-
ures 2 and 3.
Output Drive Capability
The output driver consists of a CMOS inverter capable of
driving most logic families including CMOS and TTL. As
such, if driving CMOS, the output swing at all supply volt-
ages will equal the supply voltage. At a supply voltage of
4.5V or more the ICM7555/6 will drive at least 2 standard
TTL loads.
Astable Operation
The circuit can be connected to trigger itself and free run as
a multivibrator, see Figure 2A. The output swings from rail to
rail, and is a true 50% duty cycle square wave. (Trip points
and output swings are symmetrical). Less than a 1% fre-
quency variation is observed, over a voltage range of +5V to
+15V.
1
f
= -----------------
-
1.4 RC
Monostable Operation
In this mode of operation, the timer functions as a one-shot,
see Figure 3. Initially the external capacitor (C) is held dis-
charged by a transistor inside the timer. Upon application of
a negative TRIGGER pulse to pin 2, the internal flip-flop is
set which releases the short circuit across the external
capacitor and drives the OUTPUT high. The voltage across
the capacitor now increases exponentially with a time con-
stant t = R
A
C. When the voltage across the capacitor equals
2
/ V+, the comparator resets the flip-flop, which in turn dis-
3
charges the capacitor rapidly and also drives the OUTPUT
to its low state. TRIGGER must return to a high state before
the OUTPUT can return to a low state.
t
OUTPUT
= -ln
(
1
/
3
)
R
A
C = 1.1R
A
C
1
8
7
ICM7555
6
5
OPTIONAL
CAPACITOR
V
DD
R
A
DISCHARGE
THRESHOLD
CONTROL
VOLTAGE
C
TRIGGER
OUTPUT
RESET
2
3
4
The timer can also be connected as shown in Figure 2B. In
this circuit, the frequency is:
f
=
1.44
⁄ (
R A
+
2R B
)
C
V
DD
≤18V
FIGURE 3. MONOSTABLE OPERATION
Control Voltage
The CONTROL VOLTAGE terminal permits the two trip
voltages for the THRESHOLD and TRIGGER internal
comparators to be controlled. This provides the possibility of
oscillation frequency modulation in the astable mode or even
inhibition of oscillation, depending on the applied voltage. In
the monostable mode, delay times can be changed by
varying the applied voltage to the CONTROL VOLTAGE pin.
RESET
The RESET terminal is designed to have essentially the same
trip voltage as the standard bipolar 555/6, i.e., 0.6V to 0.7V. At
all supply voltages it represents an extremely high input
impedance. The mode of operation of the RESET function is,
however, much improved over the standard bipolar 555/6 in
that it controls only the internal flip-flop, which in turn controls
simultaneously the state of the OUTPUT and DISCHARGE
pins. This avoids the multiple threshold problems sometimes
encountered with slow falling edges in the bipolar devices.
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