LM556 Dual Timer : Circuit, Application and Datasheet
5V 555 Type, Timer/Oscillator (Dual) Programmable Timers LM556 14 Pins 5V 14-DIP (0.300, 7.62mm)









5V 555 Type, Timer/Oscillator (Dual) Programmable Timers LM556 14 Pins 5V 14-DIP (0.300, 7.62mm)
LM556 is a Dual Timer. This article mainly introduce its circuit, application, datasheet and other detailed information about Texas Instruments LM556.

Alternating LEDs circuit using LM556 dual timer
LM556 Description
The LM556 dual sequential circuit is a highly stable controller that can generate precise time delays or oscillations. This 556 is double 555. Timing is provided by external resistor And the capacitor for each timing function. The two timers run independently of each other and only share VCC and ground. The circuit may be triggered and reset on falling Waveform. The output structure may sink or source 200mA.
LM556 Pinout

LM556 CAD Model
Symbol

Footprint

3D Model

LM556 Features
•Directly replace SE556/NE556
•Timekeeping from microseconds to hours
•Operate in astable and monostable mode
•Replace two 555 timers
•Adjustable duty cycle
•Output can provide or absorb 200mA
• Output and power supply TTL compatible
•Temperature stability is better than 0.005%/°C
•Normally open normally closed output
Specifications
- TypeParameter
- Mount
In electronic components, the term "Mount" typically refers to the method or process of physically attaching or fixing a component onto a circuit board or other electronic device. This can involve soldering, adhesive bonding, or other techniques to secure the component in place. The mounting process is crucial for ensuring proper electrical connections and mechanical stability within the electronic system. Different components may have specific mounting requirements based on their size, shape, and function, and manufacturers provide guidelines for proper mounting procedures to ensure optimal performance and reliability of the electronic device.
Through Hole - Mounting Type
The "Mounting Type" in electronic components refers to the method used to attach or connect a component to a circuit board or other substrate, such as through-hole, surface-mount, or panel mount.
Through Hole - Package / Case
refers to the protective housing that encases an electronic component, providing mechanical support, electrical connections, and thermal management.
14-DIP (0.300, 7.62mm) - Number of Pins14
- Operating Temperature
The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.
0°C~70°C - Packaging
Semiconductor package is a carrier / shell used to contain and cover one or more semiconductor components or integrated circuits. The material of the shell can be metal, plastic, glass or ceramic.
Tube - JESD-609 Code
The "JESD-609 Code" in electronic components refers to a standardized marking code that indicates the lead-free solder composition and finish of electronic components for compliance with environmental regulations.
e0 - Pbfree Code
The "Pbfree Code" parameter in electronic components refers to the code or marking used to indicate that the component is lead-free. Lead (Pb) is a toxic substance that has been widely used in electronic components for many years, but due to environmental concerns, there has been a shift towards lead-free alternatives. The Pbfree Code helps manufacturers and users easily identify components that do not contain lead, ensuring compliance with regulations and promoting environmentally friendly practices. It is important to pay attention to the Pbfree Code when selecting electronic components to ensure they meet the necessary requirements for lead-free applications.
no - Part Status
Parts can have many statuses as they progress through the configuration, analysis, review, and approval stages.
Obsolete - Moisture Sensitivity Level (MSL)
Moisture Sensitivity Level (MSL) is a standardized rating that indicates the susceptibility of electronic components, particularly semiconductors, to moisture-induced damage during storage and the soldering process, defining the allowable exposure time to ambient conditions before they require special handling or baking to prevent failures
1 (Unlimited) - Number of Terminations14
- ECCN Code
An ECCN (Export Control Classification Number) is an alphanumeric code used by the U.S. Bureau of Industry and Security to identify and categorize electronic components and other dual-use items that may require an export license based on their technical characteristics and potential for military use.
EAR99 - Type555 Type, Timer/Oscillator (Dual)
- Terminal Finish
Terminal Finish refers to the surface treatment applied to the terminals or leads of electronic components to enhance their performance and longevity. It can improve solderability, corrosion resistance, and overall reliability of the connection in electronic assemblies. Common finishes include nickel, gold, and tin, each possessing distinct properties suitable for various applications. The choice of terminal finish can significantly impact the durability and effectiveness of electronic devices.
Tin/Lead (Sn/Pb) - Max Power Dissipation
The maximum power that the MOSFET can dissipate continuously under the specified thermal conditions.
1.62W - Voltage - Supply
Voltage - Supply refers to the range of voltage levels that an electronic component or circuit is designed to operate with. It indicates the minimum and maximum supply voltage that can be applied for the device to function properly. Providing supply voltages outside this range can lead to malfunction, damage, or reduced performance. This parameter is critical for ensuring compatibility between different components in a circuit.
4.5V~16V - Number of Functions2
- Supply Voltage
Supply voltage refers to the electrical potential difference provided to an electronic component or circuit. It is crucial for the proper operation of devices, as it powers their functions and determines performance characteristics. The supply voltage must be within specified limits to ensure reliability and prevent damage to components. Different electronic devices have specific supply voltage requirements, which can vary widely depending on their design and intended application.
5V - Current Rating
Current rating is the maximum current that a fuse will carry for an indefinite period without too much deterioration of the fuse element.
3mA - Base Part Number
The "Base Part Number" (BPN) in electronic components serves a similar purpose to the "Base Product Number." It refers to the primary identifier for a component that captures the essential characteristics shared by a group of similar components. The BPN provides a fundamental way to reference a family or series of components without specifying all the variations and specific details.
LM556 - Pin Count
a count of all of the component leads (or pins)
14 - Supply Voltage-Max (Vsup)
The parameter "Supply Voltage-Max (Vsup)" in electronic components refers to the maximum voltage that can be safely applied to the component without causing damage. It is an important specification to consider when designing or using electronic circuits to ensure the component operates within its safe operating limits. Exceeding the maximum supply voltage can lead to overheating, component failure, or even permanent damage. It is crucial to adhere to the specified maximum supply voltage to ensure the reliable and safe operation of the electronic component.
16V - Power Supplies
an electronic circuit that converts the voltage of an alternating current (AC) into a direct current (DC) voltage.?
5/15V - Supply Voltage-Min (Vsup)
The parameter "Supply Voltage-Min (Vsup)" in electronic components refers to the minimum voltage level required for the component to operate within its specified performance range. This parameter indicates the lowest voltage that can be safely applied to the component without risking damage or malfunction. It is crucial to ensure that the supply voltage provided to the component meets or exceeds this minimum value to ensure proper functionality and reliability. Failure to adhere to the specified minimum supply voltage may result in erratic behavior, reduced performance, or even permanent damage to the component.
4.5V - Number of Channels2
- Operating Supply Current
Operating Supply Current, also known as supply current or quiescent current, is a crucial parameter in electronic components that indicates the amount of current required for the device to operate under normal conditions. It represents the current drawn by the component from the power supply while it is functioning. This parameter is important for determining the power consumption of the component and is typically specified in datasheets to help designers calculate the overall power requirements of their circuits. Understanding the operating supply current is essential for ensuring proper functionality and efficiency of electronic systems.
10mA - Nominal Supply Current
Nominal current is the same as the rated current. It is the current drawn by the motor while delivering rated mechanical output at its shaft.
3mA - Power Dissipation
the process by which an electronic or electrical device produces heat (energy loss or waste) as an undesirable derivative of its primary action.
1.62W - Quiescent Current
The quiescent current is defined as the current level in the amplifier when it is producing an output of zero.
3mA - High Level Output Current
High-level Output Current IOH The current flowing into the output at a specified high- level voltage. Low-level Output Current IOL The current flowing into the output at a specified low- level output voltage.
-200mA - Low Level Output Current
The current into the output terminal with input conditions applied that, according to the product specification, will establish a low level at the output.
200mA - Length19.18mm
- Height Seated (Max)
Height Seated (Max) is a parameter in electronic components that refers to the maximum allowable height of the component when it is properly seated or installed on a circuit board or within an enclosure. This specification is crucial for ensuring proper fit and alignment within the overall system design. Exceeding the maximum seated height can lead to mechanical interference, electrical shorts, or other issues that may impact the performance and reliability of the electronic device. Manufacturers provide this information to help designers and engineers select components that will fit within the designated space and function correctly in the intended application.
5.08mm - REACH SVHC
The parameter "REACH SVHC" in electronic components refers to the compliance with the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulation regarding Substances of Very High Concern (SVHC). SVHCs are substances that may have serious effects on human health or the environment, and their use is regulated under REACH to ensure their safe handling and minimize their impact.Manufacturers of electronic components need to declare if their products contain any SVHCs above a certain threshold concentration and provide information on the safe use of these substances. This information allows customers to make informed decisions about the potential risks associated with using the components and take appropriate measures to mitigate any hazards.Ensuring compliance with REACH SVHC requirements is essential for electronics manufacturers to meet regulatory standards, protect human health and the environment, and maintain transparency in their supply chain. It also demonstrates a commitment to sustainability and responsible manufacturing practices in the electronics industry.
No SVHC - Radiation Hardening
Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation, especially for environments in outer space (especially beyond the low Earth orbit), around nuclear reactors and particle accelerators, or during nuclear accidents or nuclear warfare.
No - RoHS Status
RoHS means “Restriction of Certain Hazardous Substances” in the “Hazardous Substances Directive” in electrical and electronic equipment.
Non-RoHS Compliant - Lead Free
Lead Free is a term used to describe electronic components that do not contain lead as part of their composition. Lead is a toxic material that can have harmful effects on human health and the environment, so the electronics industry has been moving towards lead-free components to reduce these risks. Lead-free components are typically made using alternative materials such as silver, copper, and tin. Manufacturers must comply with regulations such as the Restriction of Hazardous Substances (RoHS) directive to ensure that their products are lead-free and environmentally friendly.
Contains Lead
LM556 Functional Block Diagram

LM556 Layout Example

Where to use LM556
The LM556 IC is the dual LM555 IC, meaning the LM556 has two timers inside it. Similar to the LM555 IC, LM556 can also be used for all those applications additionally, since this works with CMOS technology, we can have two timers inside a single package with improved characteristics.
So if you are looking for a modern replacement for the 555 Timer IC, then LM556 might be the right choice for you.
How to use LM556
Application wise both 555 and 556 are the same. Since the LM556 is a 14-pin dual timer package there are two sets of all the timer pins (Threshold, Out, Trigger, Control Voltage, Discharge), and both the timer share the same Vcc and ground pins.
Timer IC’s are the most commonly used ICs for timing and Pulse generation applications. They can adapt themselves to various applications due to its different operating modes. They are very simple to understand and if we take a look at the components present inside as shown below

There are three resistors of value 5K, which gives this IC the iconic name “555 Timer”. It has dual comparators and flip-flop which will make this IC operated in three different modes such as Astable, Monostable, and Bistable(Schmitt) Mode.
LM556 Applications
•Precise timing
•Pulse generation
•Sequential timing
•Delayed generation
•Pulse width modulation
•Pulse position modulation
•Linear ramp generator
LM556 Package

LM556 Manufacturer
Texas Instruments (TI) is an American technology company headquartered in Dallas, Texas, which designs and manufactures semiconductors and various integrated circuits, and sells them to electronic designers and manufacturers worldwide. It is one of the top 10 semiconductor companies in global sales. The company focuses on the development of analog chips and embedded processors, which account for more than 80% of its revenue. TI also produces TI digital light processing technology and educational technology products, including calculators, microcontrollers and multi-core processors. As of 2016, the company has 45,000 patents worldwide.
Trend Analysis
Datasheet PDF
- PCN Obsolescence/ EOL :
- Datasheets :
1.Is LM556 used the same asNE556?
LM556 uses the same as NE556. The pin arrangement is the same. Interchangeable. The maximum power supply voltage of NE556 is 16V. The highest power supply voltage of LM556 is 18V.
2.What chips belong to timer chips?
LM556 belongs to timer chips.
3.What is the use of LM556 Dual Timer
The LM556 dual timer circuit is a highly stable controller that can generate precise time delay or oscillation. LM556 contains two LM555s, which use an external resistor and capacitor for the timing function. The two timers share a power supply and ground and work independently of each other. The circuit can trigger and reset on the falling waveform, and the output terminal can absorb or supply 200mA current
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