Datasheet LMC555CN, LMC555CMX, LMC555CMMX, LMC555CM, LMC555CBPX Datasheet (NSC)

LMC555
CMOS Timer

General Description

The LMC555 is a CMOS version of the industry standard
555 series general purpose timers. In addition to the stan­dard package(SOIC, MSOP, and MDIP) the LMC555 is also
available in achip sized package(8 Bump micro SMD) using
National’s micro SMD package technology. The LMC555 of­fers the same capability of generating accurate time delays
and frequencies as the LM555 but with much lower power
dissipation and supply current spikes. When operated as a
one-shot, the time delay is precisely controlled by a single
external resistor and capacitor. In the stable mode the oscil­lation frequency and duty cycle are accurately set by two ex­ternal resistors and one capacitor. The use of National Semi­conductor’s LMCMOS

™

process extends boththe frequency

range and low supply capability.

Features

n Less than 1 mW typical power dissipation at 5V supply
n 3 MHz astable frequency capability
n 1.5V supply operating voltage guaranteed
n Output fully compatible with TTL and CMOS logic at 5V

supply

n Tested to −10 mA, +50 mA output current levels
n Reduced supply current spikes during output transitions
n Extremely low reset, trigger, and threshold currents
n Excellent temperature stability
n Pin-for-pin compatible with 555 series of timers
n Available in 8 pin MSOP Package and 8-Bump micro

SMD package

Block and Connection Diagrams

LMCMOS™is a trademark of National Semiconductor Corp.

8-Pin SOIC, MSOP,

and MDIP Packages

DS008669-1

Top View

8-Bump micro SMD

DS008669-9

Top View

(bump side down)

February 2000

LMC555 CMOS Timer

© 2000 National Semiconductor Corporation DS008669 www.national.com

Ordering Information

Package Temperature Range Package Marking Transport Media NSC

Drawing

Industrial

−40˚C to +85˚C

8-LeadSmall Outline
(SO)

LMC555CM LMC555CM Rails

M08A

LMC555CMX LMC555CM 2.5k Units Tape and Reel

8-Lead Mini Small
Outline (MSOP)

LMC555CMM ZC5 1k Units Tape and Reel

MUA08A

LMC555CMMX ZC5 3.5k Units Tape and Reel

8-Lead Molded Dip
(MDIP)

LMC555CN LMC555CN Rails

N08E

8-Bump micro SMD LMC555CBP F1 250 Units Tape and Reel

BPA08EFB

LMC555CBPX F1 3k Units Tape and Reel

Metronome Circuit LMC555CBPEVAL N/A N/A N/A

micro SMD Marking Orientation

Top View

DS008669-23

Bumps are numbered counter-clockwise

LMC555

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Absolute Maximum Ratings (Notes 2, 3)

If Military/Aerospace specified devices are required,
please contact theNational Semiconductor SalesOffice/
Distributors for availability and specifications.

Supply Voltage, V

+

15V

Input Voltages, V

TRIG,VRES,VCTRL

,

V

THRESH

−0.3V to VS+ 0.3V

Output Voltages, V

O,VDIS

15V

Output Current I

O,IDIS

100 mA
Storage Temperature Range −65˚C to +150˚C
Soldering Information

MDIP Soldering (10 seconds) 260˚C
SOIC, MSOP Vapor Phase (60

sec) 215˚C

SOIC, MSOP Infrared (15 sec) 220˚C

Note: See AN-450 “Surface Mounting Methods and Their Effect on Product

Reliability” for other methods of soldering surface mount devices.

Operating Ratings(Notes 2, 3)

Termperature Range −40˚C to +85˚C

Thermal Resistance (θ

JA

) (Note 2)
SO, 8-lead Small Outline 169˚C/W
MSOP, 8-lead Mini Small

Outline 225˚C/W
MDIP, 8-lead Molded Dip 111˚C/W
8-Bump micro SMD 220˚C/W

Maximum Allowable Power
Dissipation

@

25˚C
MDIP-8 1126mW
SO-8 740mW
MSOP-8 555mW
8 Bump micro SMD 568mW

Electrical Characteristics (Notes 1, 2)

Test Circuit, T=25˚C, all switches open, RESET to V

S

unless otherwise noted

Symbol Parameter Conditions Min Typ Max Units

(Limits)

I

S

Supply Current V

S

=

1.5V

V

S

=

5V

V

S

=

12V

50
100
150

150
250
400

µA

V

CTRL

Control Voltage V

S

=

1.5V

V

S

=

5V

V

S

=

12V

0.8

2.9

7.4

1.0

3.3

8.0

1.2

3.8

8.6

V

V

DIS

Discharge Saturation
Voltage

V

S

=

1.5V, I

DIS

=

1mA

V

S

=

5V, I

DIS

=

10 mA

75
150

150
300

mV

V

OL

Output Voltage (Low) V

S

=

1.5V, I

O

=

1mA

V

S

=

5V, I

O

=

8mA

V

S

=

12V, I

O

=

50 mA

0.2

0.3

1.0

0.4

0.6

2.0

V

V

OH

Output Voltage
(High)

V

S

=

1.5V, I

O

=

−0.25 mA

V

S

=

5V, I

O

=

−2 mA

V

S

=

12V, I

O

=

−10 mA

1.0

4.4

10.5

1.25

4.7

11.3

V

V

TRIG

Trigger Voltage V

S

=

1.5V

V

S

=

12V

0.4

3.7

0.5

4.0

0.6

4.3

V

I

TRIG

Trigger Current V

S

=

5V 10 pA

V

RES

Reset Voltage V

S

=

1.5V (Note 4)

V

S

=

12V

0.4

0.4

0.7

0.75

1.0

1.1

V

I

RES

Reset Current V

S

=

5V 10 pA

I

THRESH

Threshold Current V

S

=

5V 10 pA

I

DIS

Discharge Leakage V

S

=

12V 1.0 100 nA

t Timing Accuracy SW 2, 4 Closed

V

S

=

1.5V

V

S

=

5V

V

S

=

12V

0.9

1.0

1.0

1.1

1.1

1.1

1.25

1.20

1.25

ms

∆t/∆V

S

Timing Shift with Supply V

S

=

5V

±

1V 0.3

%

/V

∆t/∆T Timing Shift with

Temperature

V

S

=

5V

−40˚C ≤ T ≤ +85˚C

75 ppm/˚C

f

A

Astable Frequency SW 1, 3 Closed, V

S

=

12V 4.0 4.8 5.6 kHz

f

MAX

Maximum Frequency Max. Freq. Test Circuit, V

S

=

5V 3.0 MHz

t

R,tF

Output Rise and
Fall Times

Max. Freq. Test Circuit
V

S

=

5V, C

L

=

10 pF

15 ns

LMC555

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Electrical Characteristics (Notes 1, 2)

Test Circuit, T=25˚C, all switches open, RESET to V

S

unless otherwise noted (Continued)

Symbol Parameter Conditions Min Typ Max Units

(Limits)

t

PD

Trigger Propagation Delay V

S

=

5V, Measure Delay

from Trigger to Output

100 ns

Note 1: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 2: Absolute Maximum Ratings indicate limits beyond which damagetothedevicemayoccur. Operating Ratings indicate conditions for whichthedeviceisfunc-

tional, but donotguaranteespecificperformancelimits.Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guar­antee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is
given, however, the typical value is a good indication of device performance.

Note 3: See AN-450 for other methods of soldering surface mount devices, and also AN-1112 for micro SMD considerations.
Note 4: If the RESET pin is to be used at temperatures of −20˚C and below V

S

is required to be 2.0V or greater.

Note 5: For device pinout please refer to table 1

TABLE 1. Package Pinout Names vs. Pin Function

Pin Function Package Pin numbers

8-Pin SO,MSOP, and MDIP 8-Bump micro SMD
GND 1 7
Trigger

26
Output 3 5
Reset

44
Control Voltage 5 3
Threshold 6 2
Discharge 7 1
V

+

88

Test Circuit (Note 5)

DS008669-2

Maximum Frequency Test Circuit (Note 5)

DS008669-3

LMC555

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Application Info

MONOSTABLE OPERATION

In this mode of operation, the timer functions as a one-shot
(

Figure 1

). The external capacitor is initially held discharged
by internal circuitry. Upon application of a negative trigger
pulse of less than 1/3 V

S

to the Trigger terminal, the flip-flop
is set whichboth releases theshort circuit acrossthe capaci­tor and drives the output high.

The voltage across the capacitor then increases exponen­tially for a period of t

H

=

1.1 R

A

C, which is also the time that
the output stays high, at the end of which time the voltage
equals 2/3 V

S

. The comparator then resets the flip-flopwhich
in turn discharges the capacitor and drives the output to its
low state.

Figure 2

shows the waveforms generated in this
mode of operation. Since the charge and the threshold level
of the comparator are both directly proportional to supply
voltage, the timing internal is independent of supply.

Reset overrides Trigger, which can override threshold.
Therefore the trigger pulse must be shorter than the desired
t

H

. The minimum pulse width for the Trigger is 20ns, and it is
400ns for the Reset. Duringthe timing cycle when the output
is high, the further applicationof a trigger pulse will not effect
the circuit solong as thetrigger input is returned highat least
10µs before the end of the timing interval. However the cir­cuit can be reset during this time by the application of a
negative pulse to the reset terminal. The output will then re­main in the low state until a trigger pulse is again applied.

When the reset function is not use, it is recommended that it
be connected to V

+

to avoid any possibilityof false triggering.

Figure 3

is a nomograph foreasy determination ofRC values

for various time delays.

Note: In monstable operation, the trigger should be driven high before the

end of timing cycle.

ASTABLE OPERATION

If the circuit is connected as shown in

Figure 4

(Trigger and
Threshold terminals connected together) it will trigger itself
and free run as a multivibrator. The external capacitor
charges through R

A+RB

and discharges through RB. Thus
the duty cycle may be precisely set by the ratio of these two
resistors.

In this mode of operation, the capacitor charges and dis­charges between 1/3 V

S

and 2/3 VS. As in the triggered
mode, the chargeand dischargetimes, and thereforethe fre­quency are independent of the supply voltage.

Figure 5

shows the waveform generated in this mode of

operation.

DS008669-4

FIGURE 1. Monostable (One-Shot)

DS008669-10

V

CC

=

5V Top Trace: Input 5V/Div.
TIME=0.1 ms/Div. Middle Trace: Output 5V/Div.
R

A

=

9.1kΩ Bottom Trace: Capacitor Voltage 2V/Div.

C=0.01µF

FIGURE 2. Monostable Waveforms

DS008669-11

FIGURE 3. Time Delay

DS008669-5

FIGURE 4. Astable (Variable Duty Cycle Oscillator)

LMC555

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Application Info (Continued)

The charge time (output high) is given by

t

1

=

Ln2 (R

A+RB

)C

And the discharge time (output low) by:

t

2

=

Ln2 (R

B

)C

Thus the total period is:

T=t

1+t2

=

Ln2 (R

A+RB

)C

The frequency of oscillation is:

Figure 6

may be used for quick determination of these RC
Values. The duty cycle, as a fraction of total period that the
output is low, is:

FREQUENCY DIVIDER

The monostable circuit of

Figure 1

can be used as a fre-

quency divider by adjusting the length of the timing cycle.

Figure 7

shows the waveforms generatedin a divideby three

circuit.

PULSE WIDTH MODULATOR

When the timer is connected in the monostable mode and
triggered with a continuous pulse train, the output pulse
width can be modulated by a signal applied to the Control
Voltage Terminal.

Figure 8

shows the circuit, and in

Figure 9

are some waveform examples.

PULSE POSITION MODULATOR

This application uses the timer connected for astable opera­tion, as in

Figure 10

, with a modulating signal again applied

to the control voltage terminal.The pulse position varies with

DS008669-12

V

CC

=

5V Top Trace: Output 5V/Div.
TIME=20 µs/Div. Bottom Trace: Capacitor Voltage 1V/Div.
R

A

=

3.9kΩ

R

B

=

9kΩ

C=0.01µF

FIGURE 5. Astable Waveforms

DS008669-13

FIGURE 6. Free Running Frequency

DS008669-14

V

CC

=

5V Top Trace: Input 4V/Div.
TIME=20 µs/Div. Middle Trace: Output 2V/Div.
R

A

=

9.1 kΩ Bottom Trace: Capacitor 2V/Div.

C=0.01µF

FIGURE 7. Frequency Divider Waveforms

DS008669-20

FIGURE 8. Pulse Width Modulator

DS008669-15

V

CC

=

5V Top Trace: Modulation 1V/Div.
TIME=0.2 ms/Div. Bottom Trace: Output Voltage 2V/Div.
R

A

=

9.1 kΩ

C=0.01µF

FIGURE 9. Pulse Width Modulator Waveforms

LMC555

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Application Info (Continued)

the modulating signal,since the thresholdvoltage and hence
the time delay is varied.

Figure 11

shows the waveforms

generated for a triangle wave modulation signal.

50%DUTY CYCLE OSCILLATOR

The frequency of oscillation is

f=1/(1.4 R

C

C)

DS008669-21

FIGURE 10. Pulse Position Modulator

DS008669-16

V

CC

=

5V Top Trace: Modulation Input 1V/Div.
TIME=0.1 ms/Div. Bottom Trace: Output Voltage 2V/Div.
R

A

=

3.9 kΩ

R

B

=

3kΩ

C=0.01µF

FIGURE 11. Pulse Position Modulator Waveforms

DS008669-6

FIGURE 12. 50%Duty Cycle Oscillator

LMC555

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Physical Dimensions inches (millimeters) unless otherwise noted

Molded Small Outline (SO) Package (M)

NS Package Number M08A

LMC555

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

8-Lead (0.118” Wide) Molded Mini Small Outline Package

NS Package Number MUA08A

LMC555

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

Molded Dual-in-line Package (N)

NS Package Number N08E

LMC555

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

NOTES: UNLESS OTHERWISE SPECIFIED

1. EPOXY COATING

2. 63Sn/37Pb EUTECTIC BUMP

3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD.

4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE
NUMBERED COUNTERCLOCKWISE.

5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACK­AGE LENGTH AND X3 IS PACKAGE HEIGHT.

6. REFERENCE JEDEC REGISTRATION MO-211, VARIATION BC.

micro SMD Package

NS Package Number BPA08EFB

X

1

=

1.387 X

2

=

1.412 X

3

=

0.850

LMC555

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Notes

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.

2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.

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Corporation

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LMC555 CMOS Timer

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.