NE556N Dual Timer IC

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Pin Configuration

Pin NumberPin NameDescription
1,13DischargeOpen collector output which discharges a capacitor between intervals (in phase with output). 7 I It toggles the output from high to low when voltage reaches 2/3 of the supply voltage
2,12ThresholdCompares the voltage applied to the terminal with a reference voltage of 2/3 Vcc. The 6 I amplitude of voltage applied to this terminal is responsible for the set state of the flip-flop
3,11Control VoltageControls the threshold and trigger levels. It determines the pulse width of the output 5 Voltage I waveform. An external voltage applied to this pin can also be used to modulate the output waveform
4,10ResetNegative pulse applied to this pin to disable or reset the timer. When not used for reset 4 I purposes, it should be connected to VCC to avoid false triggering
5,9OutThis pin is normally connected to load as it is the only pin with output driven waveform
6,8TriggerResponsible for transition of the flip-flop from set to reset. The output of the timer depends 2 I on the amplitude of the external trigger pulse applied to this pin
7GroundGround Reference Voltage 0V
14VccSupply Voltage (Typical = 5V, Maximum = 18V)


  • Two precision Timers in one single package
  • Typical operating voltage is +5V, can withstand a maximum of +18V.
  • The source/sink current of the output pin is 150mA
  • Minimum Threshold voltage is 2.4 @ Vcc=5V
  • Operating Temperature is 70 degree Celsius.
  • Available in 14-pin PDIP, SOIC, and VSSOP packages.

Where to use NE556 IC

The NE556 IC is the dual version of NE555 IC, meaning the NE556 has two timers inside it. As we know 555 ICs have been used for a long time now due to their reliable properties and applications. The NE556 can also be used for all those application 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 NE556 might be the right choice for you.

Difference Between 555 and 556 IC

The NE556 is the successor of the classic 555 Timer IC. It has two Timers inside a single package. This reduces the form factor and complexity of the system. Functionality and pin description wise both 555 and 556 are identical.

How to use NE556 IC

Application wise both NE555 and NE556 are one and the same, so if you want to know the basic of the Timer IC then read through the NE555 page. Since the NE556 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 adopt itself into 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.

NE556 IC Inside Components

There are three resistors of value 5K, which gives this IC it’s iconic name “555 Timer”. It has dual comparators and flip-flop which will make this IC operated in three different modes such as AstableMonostable and Bistable(Schimitt) Mode.  


  • Time Delay Generation
  • Pulse Width Modulation
  • Pulse generation
  • Precision Timing
  • Sequential Timing circuits

Farees Ahmed

The aim of this blog is to serve as a quick reference guide for the Curious. Appreciate your feedback and comments !