NE556 Dual Timer IC Pin Layout, Features, Application, Specifications, etc.

The 555 Timer IC is a versatile and widely-used component in electronic circuits, functioning as a timer, pulse generator, and oscillator. This integrated circuit is capable of serving as a delay device, trigger source, or resonator element, making it a foundational element in electronics. Below, we’ll explore the design, pinout configuration, internal structure, operating modes, and derivatives of the 555 Timer IC.

Catalog

Overview of the 555 Timer

The 555 timer, a remarkable creation by Hans R. Camenzind for Signetics in 1971, has carved a lasting niche in the realm of electronics due to its affordability, reliability, and user-friendly nature. Following its invention, it was incorporated into Philips’ portfolio and is now produced by numerous companies, embodying both bipolar transistors and CMOS architectures. This innovation reached a milestone with 1 billion units produced by 2003, highlighting its enduring resonance. Typically, the classic 555 timer includes 25 transistors, 2 diodes, and 15 resistors within an 8-pin DIP-8 package. Additional variations like the 556 with dual timers in a 14-pin package, along with the 558 and 559 models, offer extra capabilities.

The NE556 operates effectively in temperature ranges from 0 to 70°C, catering to standard applications, while the SE555 version endures more extreme environments from -55°C to +125°C, making it suitable for military use. This adaptability illustrates its utility across various domains, from basic timers and oscillators to complex tone generators and sequential timers. The original design offers diverse packaging options, with robust metal choices and economical epoxy resin versions. The famous '555' designation, intriguingly, was not derived from the three 5kΩ resistors, contrary to popular belief, but chosen arbitrarily, reflecting the oft-irreverent path of innovation.

NE556 Pin Layout

The 555 timer, housed in a DIP package, features a structured arrangement of eight unique pins, each with specific responsibilities. This section explores the functionality of each pin and their applications, offering insights that enhance circuit design and troubleshooting.

GND and VCC

Pin 1, or GND (Ground), serves as the 0-volt reference point, establishing circuit stability's foundation. Opposite lies Pin 8, marked VCC, which delivers power to the chip and dictates its performance level. Grasping this power setup enriches one's understanding of electronic devices' stable functioning, encouraging thoughtful design considerations.

TRIG

Utilizing Pin 2, TRIG (Trigger), the timer switches to a high output when input voltage falls below a third of the total supplied voltage. This mechanism holds particular significance in timing applications, frequently used to generate pulse signals where precision timing plays a decisive role in important implementations.

OUT and RST

Pin 3, known as OUT, operates as the main output, toggling between high and low states, thus allowing effective regulation of digital signals. Working alongside, Pin 4 (RST or Reset) can shift the timer to a low state when grounded, a helpful feature in contexts requiring abrupt halting of circuits.

CTRL

Referred to as CTRL (Control), Pin 5 provides adaptability by allowing internal threshold voltage adjustments. This flexibility benefits the fine-tuning of the timer's behavior across different applications, like modifying signal frequency without external input, underscoring the 555 timer's versatility.

THR and DIS

Pin 6, THR (Threshold), impacts the output transition by reducing it once voltage hits two-thirds of VCC. Conversely, DIS (Discharge) at Pin 7 manages internal capacitor discharge, vital for oscillator functions. Skillfully managing charging and discharging processes enhances control over timing and oscillating circuits. Appreciating these detailed interactions provides substantial improvements in circuit adaptation to diverse operational conditions, showcasing the enduring versatility of the 555 timer.

Features of NE556

Feature	Description
Fast and Precise Timing	Supports rapid operations with frequencies over 500 kHz, suitable for precise timing tasks like clock generation and signal modulation.
Broad Timing Flexibility	Manages timing intervals from microseconds to hours, ideal for both short bursts and long-duration processes.
Dual Operational Modes	- Astable Mode: Generates continuous oscillations for clock signals.
	- Monostable Mode: Produces a single pulse when triggered, useful for timers.
High Output Driving Capability	Can source or sink up to 200 mA, enabling direct driving of LEDs, relays, and small motors, reducing the need for additional driver circuits.
Adjustable Output Duty Cycle	Provides control over the ON/OFF ratio of the output waveform, essential for regulating motor speed and adjusting LED brightness.
Seamless Integration with TTL	Compatible with TTL logic, allowing for straightforward integration into digital circuits and facilitating analog-digital interactions.
Stable Performance in Extreme Temperatures	Offers consistent performance in diverse thermal conditions, crucial for operation in sensitive or mission-critical applications.

Guide to Using the NE556 Timer IC

The NE556 and NE555 timer ICs are very similar in function, with the main difference being that the NE556 combines two timers into one chip. It is packaged in a 14-pin design, while the NE555 is a single-timer IC. If you already understand the NE555, learning how the NE556 works will be easy. The NE556 has two independent timer circuits, each with its own dedicated pins: Threshold, Trigger, Control Voltage, Output, and Discharge. Both timers share the same power supply (Vcc) and ground connections.

Timer ICs like the NE556 are highly adaptable and are frequently used in tasks that require accurate timing or pulse generation. Their design allows them to operate in different modes, making them suitable for many applications. These ICs are relatively simple to use, especially if you take the time to understand how their internal components work.

Inside the NE556, there are three resistors, each with a value of 5kΩ, which is where the "555" name originates. The IC also contains two comparators and a flip-flop circuit. These components allow the NE556 to operate in three distinct modes: Astable, Monostable, and Bistable (Schmitt Trigger). Thanks to this versatility, the NE556 can be used in applications such as oscillators, pulse generators, timers, and other circuits requiring precise timing functionality.

Application of NE556 Timer

The NE556 IC is an advanced version of the popular NE555 timer IC, containing two timers in one unit. This dual functionality, combined with its CMOS technology, offers enhanced features in a single package.It maintains all the trusted applications of the 555 IC but with improved performance.

Key Uses of the NE556 IC

The NE556 is versatile, supporting various applications such as:

Pulse Shaping Circuits: Ideal for generating precise pulse outputs needed in digital communications.

Tone Generation: Used in audio systems to produce specific tones.

Frequency Dividers: Splits input frequencies, useful in timing and clock operations.

Missing Pulse Detectors: Detects missing pulses in a sequence, critical for data transmission.

Industrial Controls: Adapts well to automation and control systems in industrial environments.

Touch Tone Encoders: Generates tones for telecommunication interfaces.

NE556 Specifications

Parameter	Value
Mounting Type	Through Hole
Package / Case	14-DIP (0.300, 7.62mm)
Weight	1.620005g
Packaging	Tube
Part Status	Obsolete
Number of Terminations	14
Type	555 Type, Timer/Oscillator (Dual)
Voltage - Supply	4.5V–16V
Supply Voltage	5V
Frequency	500kHz
Pin Count	14
Power Supplies	5/15V
Number of Channels	2
Nominal Supply Current	20mA
Quiescent Current	4mA
Low Level Output Current	200mA
Length	19.05mm
REACH SVHC	No SVHC
RoHS Status	RoHS3 Compliant
Operating Temperature	0°C–70°C
JESD-809 Code	e4
Moisture Sensitivity Level (MSL)	1 (Unlimited)
ECCN Code	EAR99
Terminal Finish	Nickel/Palladium/Gold (Ni/Pd/Au)
Number of Functions	2
Current Rating	20A
Base Part Number	NE556
Supply Voltage-Max (Vsup)	16V
Supply Voltage-Min (Vsup)	4.5V
Operating Supply Current	20mA
Output Current	200mA
High Level Output Current	-200mA
Height	3.3mm
Width	8.35mm
Radiation Hardening	No
Lead Free	Lead Free

Block Diagram

Schematic Diagram

NE556 Alternative Models

Part Number	Description	Manufacturer
ICM7556IPDZ	General Purpose Timers	Renesas Electronics Corporation
TLC556IN	15V Dual LinCMOS timer 14-PDIP	Texas Instruments
NE556N	IC Dual Pulse, Rectangular, 0.5 MHz, Timer, PDIP14, 0.300 Inch, Plastic, DIP-14, Analog Waveform Generation Function	NXP Semiconductors
ICM7556IMJD	Analog Waveform Generation Function	Renesas Electronics Corporation
556-1/BCA	2 Func, BiPolar, CDIP14	Yageo Corporation
LM556J	Dual Rectangular, Timer, CDIP14, Ceramic, DIP-14	Texas Instruments
ICM7555IPD	Analog Circuit	Thomson Consumer Electronics
5962-8950302CA	Low-Power Dual LinCMOS™ Timer 14-CDIP -55 to 125	Texas Instruments
SA556	IC Timer, CDIP14, Analog Waveform Generation Function	NXP Semiconductors
5962-8950304CA	1 Func, CMOS, CDIP14	Harris Semiconductor

Typical Application Circuit

Manufacturer

STMicroelectronics is a leading global semiconductor manufacturer renowned for its advanced solutions in various microelectronics applications. With expertise in silicon design and system-level innovation, coupled with strong manufacturing capabilities and a rich IP portfolio, STMicroelectronics excels in System-on-Chip (SoC) technology. This positions the company at the forefront of industry advancements, influencing sectors like automotive, consumer electronics, and industrial applications. Its technology integration enables sophisticated systems that combine sensors, processors, and connectivity solutions. STMicroelectronics maintains its industry leadership by focusing on innovation and adaptability to meet the dynamic demands of the technology sector.

Datasheet PDF

NE556 Datasheet:

Frequently Asked Questions [FAQ]

1. What is the purpose of a 555 timer?

The 555 timer IC is a versatile and affordable timing device used to generate precise time delays or single pulses. It can also function as a relaxation oscillator, producing a continuous waveform with varying duty cycles, typically ranging from 50% to 100%.

2. What is the maximum speed of a 555 timer?

The LMC555, a CMOS version of the 555 timer, is the fastest model available, capable of operating at frequencies up to 3 MHz according to the datasheet. It is available in several 8-pin package options like DIP, SOIC, and VSSSOP.

3. How do you set up a 555 timer?

To use a 555 timer, you can configure it as an Astable Multivibrator by connecting two resistors and a capacitor to the basic IC. This setup determines the duration for which the output stays high or low, generating a square wave (clock signal) with alternating high and low states.

4. How do you trigger a 555 timer?

A 555 timer is typically triggered by applying a negative pulse to its trigger pin (pin 2). In the monostable mode, this negative pulse starts the timing cycle. Alternatively, it can be triggered through a positive pulse on its reset pin.

5. How precise is a 555 timer?

The 555 timer is suitable for applications requiring less than 1% accuracy. For higher precision (better than 0.1%), it’s better to use digital or crystal-based timing solutions. Additionally, the 555 timer may experience jitter if the supply voltage fluctuates rapidly during its timing cycle.