LM556
LM556 Dual Timer
Literature Number: SNAS549
LM556
Dual Timer
General Description
The LM556 Dual timing circuit is a highly stable controller ca-
pable of producing accurate time delays or oscillation. The
556 is a dual 555. Timing is provided by an external resistor
and capacitor for each timing function. The two timers oper-
ate independently of each other sharing only V
CC
and
ground. The circuits may be triggered and reset on falling
waveforms. The output structures may sink or source
200mA.
Features
nDirect replacement for SE556/NE556
nTiming from microseconds through hours
nOperates in both astable and monostable modes
nReplaces two 555 timers
nAdjustable duty cycle
nOutput can source or sink 200mA
nOutput and supply TTL compatible
nTemperature stability better than 0.005% per ˚C
nNormally on and normally off output
Applications
nPrecision timing
nPulse generation
nSequential timing
nTime delay generation
nPulse width modulation
nPulse position modulation
nLinear ramp generator
Connection Diagram
Ordering Information
Package Part Number Package Marking Media Transport NSC Drawing
14-Pin SOIC LM556CM LM556CM Rails M14A
LM556CMX LM556CM 2.5k Units Tape and Reel
14-Pin MDIP LM556CN LM556CN Rails N14a
Dual-In-Line, Small Outline Packages
DS007852-1
Top View
March 2000
LM556 Dual Timer
© 2000 National Semiconductor Corporation DS007852 www.national.com
Schematic Diagram
DS007852-2
LM556
www.national.com 2
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage +18V
Power Dissipation (Note 2)
LM556CM 410 mW
LM556CN 1620 mW
Operating Temperature Ranges
LM556C 0˚C to +70˚C
Storage Temperature Range −65˚C to +150˚C
Soldering Information
Dual-In-Line Package
Soldering (10 Seconds) 260˚C
Small Outline Packages
Vapor Phase (60 Seconds) 215˚C
Infrared (15 Seconds) 220˚C
See AN-450 “Surface Mounting Methods and Their Effect
on Product Reliability” for other methods of soldering
surface mount devices.
Electrical Characteristics
(T
A
= 25˚C, V
CC
= +5V to +15V, unless otherwise specified)
Parameter Conditions Limits Units
LM556C
Min Typ Max
Supply Voltage 4.5 16 V
Supply Current
(Each Timer Section) V
CC
= 5V, R
L
=∞
V
CC
= 15V, R
L
=∞
(Low State) (Note 3)
3
10 6
14 mA
Timing Error, Monostable
Initial Accuracy 0.75 %
Drift with Temperature R
A
= 1k to 100kΩ, 50 ppm/˚C
C = 0.1µF, (Note 4)
Accuracy over Temperature 1.5 %
Drift with Supply 0.1 %/V
Timing Error, Astable
Initial Accuracy 2.25 %
Drift with Temperature R
A
,R
B
= 1k to 100kΩ, 150 ppm/˚C
Accuracy over Temperature C = 0.1µF, (Note 4) 3.0 %
Drift with Supply 0.30 %/V
Trigger Voltage V
CC
= 15V 4.5 5 5.5 V
V
CC
= 5V 1.25 1.67 2.0 V
Trigger Current 0.2 1.0 µA
Reset Voltage 0.4 0.5 1 V
Reset Current 0.1 0.6 mA
Threshold Current V
TH
= V-Control (Note 6)
V
TH
= 11.2V 0.03 0.1
250 µA
nA
Control Voltage Level and
Threshold Voltage V
CC
= 15V
V
CC
=5V 9
2.6 10
3.33 11
4V
Pin 1, 13
Leakage Output High 1 100 nA
Pin 1, 13 Sat (Note 7)
Output Low V
CC
= 15V, I = 15mA 180 300 mV
Output Low V
CC
= 4.5V, I = 4.5mA 80 200 mV
Output Voltage Drop (Low) V
CC
= 15V
I
SINK
= 10mA 0.1 0.25 V
I
SINK
= 50mA 0.4 0.75 V
I
SINK
= 100mA 2 2.75 V
I
SINK
= 200mA 2.5 V
V
CC
=5V
I
SINK
= 8mA V
I
SINK
= 5mA 0.25 0.35 V
LM556
www.national.com3
Electrical Characteristics (Continued)
(T
A
= 25˚C, V
CC
= +5V to +15V, unless otherwise specified)
Parameter Conditions Limits Units
LM556C
Min Typ Max
Output Voltage Drop (High) I
SOURCE
= 200mA, V
CC
= 15V 12.5 V
I
SOURCE
= 100mA, V
CC
= 15V 12.75 13.3 V
V
CC
= 5V 2.75 3.3 V
Rise Time of Output 100 ns
Fall Time of Output 100 ns
Matching Characteristics (Note 8)
Initial Timing Accuracy 0.1 2.0 %
Timing Drift with Temperature ±10 ppm/˚C
Drift with Supply Voltage 0.2 0.5 %/V
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.
Note 2: For operating at elevated temperatures the device must be derated based on a +150˚C maximum junction temperature and a thermal resistance of 77˚C/W
(Plastic Dip), and 110˚C/W (SO-14 Narrow).
Note 3: Supply current when output high typically 1mA less at VCC =5V.
Note 4: Tested at VCC = 5V and VCC = 15V.
Note 5: As reset voltage lowers, timing is inhibited and then the output goes low.
Note 6: This will determine the maximum value of RA+R
Bfor 15V operation. The maximum total (RA+R
B
)is20MΩ.
Note 7: No protection against excessive pin 1, 13 current is necessary providing the package dissipation rating will not be exceeded.
Note 8: Matching characteristics refer to the difference between performance characteristics of each timer section.
Note 9: Refer to RETS556X drawing of military LM556J versions.
Typical Performance Characteristics
Minimum Pulse Width Required for Triggering
DS007852-3
Supply Current vs. Supply Voltage (Each Section)
DS007852-4
LM556
www.national.com 4
Typical Performance Characteristics (Continued)
High Output Voltage vs. Output Source Current
DS007852-5
Low Output Voltage vs. Output Sink Current
DS007852-6
Low Output Voltage vs. Output Sink Current
DS007852-7
Low Output Voltage vs. Output Sink Current
DS007852-8
Output Propagation Delay vs. Voltage Level of Trigger
Pulse
DS007852-9
Output Propagation Delay vs. Voltage Level of Trigger
Pulse
DS007852-10
LM556
www.national.com5
Typical Performance Characteristics (Continued)
Discharge Transistor (Pin 1, 13) Voltage vs. Sink
Current
DS007852-11
Discharge Transistor (Pin 1, 13) Voltage vs. Sink
Current
DS007852-12
LM556
www.national.com 6
Physical Dimensions inches (millimeters) unless otherwise noted
Small Outline Package (M)
NS Package Number M14A
14-Lead (0.118” Wide) Molded Mini Small Outline Package
NS Package Number N14A
LM556
www.national.com7
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.
National Semiconductor
Corporation
Americas
Tel: 1-800-272-9959
Fax: 1-800-737-7018
Email: support@nsc.com
National Semiconductor
Europe Fax: +49 (0) 180-530 85 86
Email: europe.support@nsc.com
Deutsch Tel: +49 (0) 69 9508 6208
English Tel: +44 (0) 870 24 0 2171
Français Tel: +33 (0) 1 41 91 8790
National Semiconductor
Asia Pacific Customer
Response Group
Tel: 65-2544466
Fax: 65-2504466
Email: ap.support@nsc.com
National Semiconductor
Japan Ltd.
Tel: 81-3-5639-7560
Fax: 81-3-5639-7507
www.national.com
LM556 Dual 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.
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are
sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where
mandated by government requirements, testing of all parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual
property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional
restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not
responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in
such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic."Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated
products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products Applications
Audio www.ti.com/audio Communications and Telecom www.ti.com/communications
Amplifiers amplifier.ti.com Computers and Peripherals www.ti.com/computers
Data Converters dataconverter.ti.com Consumer Electronics www.ti.com/consumer-apps
DLP®Products www.dlp.com Energy and Lighting www.ti.com/energy
DSP dsp.ti.com Industrial www.ti.com/industrial
Clocks and Timers www.ti.com/clocks Medical www.ti.com/medical
Interface interface.ti.com Security www.ti.com/security
Logic logic.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense
Power Mgmt power.ti.com Transportation and Automotive www.ti.com/automotive
Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video
RFID www.ti-rfid.com
OMAP Mobile Processors www.ti.com/omap
Wireless Connectivity www.ti.com/wirelessconnectivity
TI E2E Community Home Page e2e.ti.com
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright ©2011, Texas Instruments Incorporated
