NE555 in 8-pinType,InventedFirst production1971Internal block diagramThe 555 timer IC is an (chip) used in a variety of, pulse generation, and applications. The 555 can be used to provide time delays, as an, and as a. Derivatives provide two or four timing circuits in one package.Introduced in 1972 by, the 555 is still in widespread use due to its low price, ease of use, and stability. It is now made by many companies in the original and in low-power technologies. As of 2003, it was estimated that 1 billion units were manufactured every year. The 555 is the most popular integrated circuit ever manufactured.
Die of the first 555 chip (1971)The IC was designed in 1971 by under contract to, later acquired by, now.In 1962, Camenzind joined PR Mallory's Laboratory for Physical Science in. He designed a (PWM) amplifier for audio applications; however, it was not successful in the market because there was no power transistor included. He became interested in tuners such as a and a (PLL). He was hired by Signetics to develop a PLL IC in 1968. He designed an oscillator for PLLs such that the frequency did not depend on the power supply voltage or temperature. Signetics subsequently laid off half of its employees due to a; development on the PLL was thus frozen.Camenzind proposed the development of a universal circuit based on the oscillator for PLLs and asked that he develop it alone, borrowing equipment from Signetics instead of having his pay cut in half.
Other engineers argued the product could be built from existing parts; however, the marketing manager bought the idea. Among 5xx numbers that were assigned for analog ICs, the special number '555' was chosen.Camenzind also taught circuit design at in the morning attending the university himself at night working toward a Master's degree in Business Administration. The first design for the 555 was reviewed in the summer of 1971. Assessed to be without error, it proceeded to layout design.
A few days later, Camenzind got the idea of using a direct resistance instead of a constant current source finding later that it worked. The change decreased the required 9 pins to 8 so the IC could be fit in an 8-pin package instead of a 14-pin package. This revised design passed a second design review with the prototype completed in October 1971.
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The 9-pin copy had been already released by another company founded by an engineer who attended the first review and retired from Signetics; that firm withdrew its version soon after the 555 was released. The 555 timer was manufactured by 12 companies in 1972 and it became a best selling product. Part name It has been falsely hypothesized that the 555 got its name from the three 5 used within. Hans Camenzind has stated that the part number was arbitrary, thus it was simply a coincidence they matched. The 'NE' and 'SE' letters of the original parts numbers (NE555 and SE555) were temperature designations for analog chips from Signetics, where 'NE' was commercial temperature family and 'SE' was military temperature family.Design Depending on the manufacturer, the standard 555 package includes 25, 2 and 15 on a chip installed in an 8-pin (DIP-8).
Variants available include the 556 (a DIP-14 combining two complete 555s on one chip), and 558 / 559 (both a DIP-16 combining four reduced-functionality timers on one chip).The NE555 parts were commercial temperature range, 0 °C to +70 °C, and the SE555 part number designated the military temperature range, −55 °C to +125 °C. These were available in both high-reliability metal can (T package) and inexpensive epoxy plastic (V package) packages.
Thus the full part numbers were NE555V, NE555T, SE555V, and SE555T.Low-power CMOS versions of the 555 are also available, such as the Intersil ICM7555 and Texas Instruments LMC555, TLC555, TLC551. CMOS timers use significantly less power than bipolar timers; CMOS timers also cause less supply noise than bipolar version when the output switches states.
The ICM7555 datasheet claims that it usually doesn't require a 'control' capacitor and in many cases does not require a across the power supply pins. A decoupling capacitor reduces noise or variation in power supply voltage that may affect other parts of a circuit or affect the timer's threshold voltages.Internal schematic The internal and of the 555 timer are highlighted with the same color across all three drawings to clarify how the chip is implemented:. Green: Between the positive supply voltage V CC and the ground GND is a consisting of three identical, which create two reference voltages at 1⁄ 3 V CC and 2⁄ 3 V CC.
The latter is connected to the 'Control Voltage' pin. All three resistors have the same resistance, 5 for bipolar timers, 100 kΩ (or higher resistance values) for CMOS timers. It is a false myth that the 555 IC got its name from these three 5 kΩ resistors.
Yellow: The negative input is connected to the higher-reference voltage divider of 2⁄ 3 V CC (and 'Control' pin), and comparator positive input is connected to the 'Threshold' pin. Red: The comparator positive input is connected to the lower-reference voltage divider of 1⁄ 3 V CC, and comparator negative input is connected to the 'Trigger' pin. Purple: An stores the state of the timer and is controlled by the two comparators.
The 'Reset' pin overrides the other two inputs, thus the flip-flop (and therefore the entire timer) can be reset at any time. Pink: The output of the flip-flop is followed by an output stage with (P.P.) output drivers that can load the 'Output' pin with up to 200 mA (varies by device). Cyan: Also, the output of the flip-flop turns on a that connects the 'Discharge' pin to ground.
555 internal schematic of CMOS versionPinout The typical pinout of the 555 and 556 IC packages are as follows: 555 Pin#556 Pin#Pin namePin directionPin purpose17GNDPowerGround supply: this pin is the reference voltage (zero volts).26, 8TRIGInputTrigger: when the voltage at this pin falls below 1⁄ 2 of CONT pin voltage ( 1⁄ 3 V CC except when CONT is driven by an external signal), the OUT pin goes high and a timing interval starts. As long as this pin continues to be kept at a low voltage, the OUT pin will remain high.35,9OUTOutputOutput: this is a (P.P.) output that is driven to either a low state (ground supply at GND pin) or a high state ( at V CC pin minus approximately 1.7 Volts). (Note: For CMOS timers, the high state is driven to V CC.) When bipolar timers are used in applications where the output drives a TTL input, a 100 to 1000 may need to be added to prevent double triggering.44,10RESETInputReset: a timing interval may be reset by driving this pin to GND, but the timing does not begin again until this pin rises above approximately 0.7 Volts. This pin overrides TRIG (trigger), which overrides THRES (threshold). In most applications this pin is not used, thus it should be connected to V CC to prevent electrical noise causing a reset.53,11CONTInputControl (or Control Voltage): this pin provides access to the internal ( 2⁄ 3 V CC by default). By applying a voltage to the CONT input one can alter the timing characteristics of the device. In most applications this pin is not used, thus a 10 ( or ) should be connected between this pin and GND to ensure electrical noise doesn't affect the internal voltage divider.
Pinout of 556 dual timer (14 pins) (conceptually two 555 timers)Modes The IC 555 has three operating modes:. (free-running) mode – the 555 can operate as an. Uses include and lamp flashers, pulse generation, logic clocks, tone generation, security alarms, and so on. The 555 can be used as a simple, converting an analog value to a pulse length (e.g., selecting a as timing resistor allows the use of the 555 in a temperature sensor and the period of the output pulse is determined by the temperature). The use of a microprocessor-based circuit can then convert the pulse period to temperature, linearize it and even provide calibration means. mode – in this mode, the 555 functions as a 'one-shot' pulse generator.
Applications include timers, missing pulse detection, bounce-free switches, touch switches, frequency divider, capacitance measurement, (PWM) and so on. mode – the 555 can operate as a, if the DIS pin is not connected and no capacitor is used. Uses include bounce-free latched switches.Astable. See also:In bistable mode, the 555 timer acts as a basic flip-flop. The trigger and reset inputs (pins 2 and 4 respectively on a 555) are held high via while the threshold input (pin 6) is grounded.
Thus configured, pulling the trigger momentarily to ground acts as a 'set' and transitions the output pin (pin 3) to V CC (high state). Pulling the reset input to ground acts as a 'reset' and transitions the output pin to ground (low state). No timing capacitors are required in a bistable configuration.
Pin 7 (discharge) is left unconnected, or may be used as an output.A 555 timer can be used to create a which converts a noisy input into a clean digital output. The input signal should be connected through a series capacitor which then connects to the trigger and threshold pins. A resistor divider, from V CC to GND, is connected to the previous tied pins. The reset pin is tied to V CC. Texas Instruments NE555 in DIP-8 and SO-8 packagesThese specifications apply to the bipolar NE555.
Other 555 timers can have different specifications depending on the grade (military, medical, etc.). Die of a NE558D quad timer manufactured. Table notes. All information in the above table was pulled from references in the datasheet column, except where denoted below. For 'Timer Total' column, a '.' denotes parts that are missing 555 timer features. For 'I q' column, a 5 volt supply was chosen as a common voltage to make it easier to compare.
The value for Signetics NE558 is an estimate, because NE558 datasheets don't state I q at 5V. The value listed in this table was estimated by comparing the 5V to 15V ratio of other bipolar datasheets, then derating the 15V parameter for the NE558 part, which is denoted by the '.' .
For 'Frequency Max' column, a '.' denotes values that may not be the actual maximum frequency limit of the part. The MIC1555 datasheet discusses limitations from 1 to 5 MHz. Though most bipolar timers don't state the maximum frequency in their datasheets, they all have a maximum frequency limitation of hundreds of kHz across their full temperature range. Section 8.1 of the Texas Instruments NE555 datasheet states a value of 100 kHz, and their website shows a value of 100 kHz in timer comparison tables, which is overly conservative. In Signetics App Note 170, states that most devices will oscillate up to 1 MHz, however when considering temperature stability it should be limited to about 500 kHz.Table manufacturer notesOver the years, numerous IC companies have merged.
The new parent company inherits everything from the previous company then datasheets and chip logos are changed over a period of time to the new company. This information is useful when tracking down datasheets for older parts. Instead of including every related company in the above table, only one name is listed, and the following list can be used to determine the relationship. was sold to in 2016. Micrel was sold to in 2015. was sold to in 2011. was sold to in 1975, later to in 2006.
was sold to in 2008.556 dual timer The dual version is called 556. It features two complete 555s in a 14 pin package. Only the two power supply pins are shared between the two timers. Bipolar version are currently available, such as the NE556 and LM556.
CMOS versions are currently available, such as the Intersil ICM7556 and Texas Instruments TLC556 and TLC552, see. 558 quad timer.
Pinout of 558 quad timer (16 pins). The 558 timers are different than 555 timer (obsolete part)The quad version is called 558. It has four reduced-functionality timers in a 16 pin package (four complete 555 timer circuits would have required 26 pins). Since the 558 is uniquely different than the 555 and 556, the 558 was not as popular. Currently the 558 is not manufactured by any major chip companies (possibly not by any companies), thus the 558 should be treated as obsolete.
Game Control Adapter(8-bit card)The used a quad timer 558 in monostable (or 'one-shot') mode to interface up to four 'game paddles' or two to the host computer. It also used a single 555 for flashing the display cursor.The original used a similar circuit for the on the 'Game Control Adapter' 8-bit card (IBM part number 1501300). In this joystick interface circuit, the of the (see Monostable Mode above) was generally a 10 capacitor to ground with a series 2.2 KΩ to the game port connector. The external joystick was plugged into the adapter card.
Internally it had two (100 to 150 KΩ each), one for X and other for Y direction. The center wiper pin of the potentiometer was connected to an Axis wire in the cord and one end of the potentiometer was connected to the 5 Volt wire in the cord.
The joystick potentiometer acted as a variable resistor in the RC network. By moving the joystick, the resistance of the joystick increased from a small value up to about 100 kΩ.Software running in the IBM PC computer started the process of determining the joystick position by writing to a special address ( I/O address 201h). This would result in a trigger signal to the quad timer, which would cause the capacitor of the RC network to begin charging and cause the quad timer to output a pulse. The width of the pulse was determined by how long it took the capacitor to charge up to 2⁄ 3 of 5 V (or about 3.33 V), which was in turn determined by the joystick position.
The software then measured the pulse width to determine the joystick position. A wide pulse represented the full-right joystick position, for example, while a narrow pulse represented the full-left joystick position. See also.,.,.,References. September 2014. (PDF) from the original on June 28, 2017. Retrieved June 28, 2017. ^ (PDF).
From the original on April 5, 2016. Retrieved June 29, 2017.
(see 555/556/558 datasheets and AN170/AN171 appnotes). ^ Fuller, Brian (15 August 2012). Retrieved 27 December 2016.
^. From the original on January 9, 2013. Retrieved June 28, 2017. ^.
Tony R. 'Lessons In Electric Circuits: Volume VI - Experiments'. Albert Lozano. Camenzind, Hans (11 Feb 1966).
Solid-State Circuits Conference. Digest of Technical Papers. 1966 IEEE International: 90–91. ^ Carmenzind, Hans (2010).
Translated by 三宅, 和司. 'タイマIC 555 誕生秘話' The birth of the 555 timer IC. トランジスタ技術 (Transistor Technology) (in Japanese).
47 (12): 73, 74. Scherz, Paul (2000) 'Practical Electronics for Inventors', p. McGraw-Hill/TAB Electronics. Retrieved 2010-04-05. van Roon, Fig 3 & related text.
^. From the original on October 4, 2012. Retrieved June 28, 2017. ^ (PDF).
(PDF) from the original on June 29, 2017. Retrieved June 29, 2017. ^ (PDF). (PDF) from the original on June 28, 2017. Retrieved June 28, 2017. ^ (PDF). (PDF) from the original on June 28, 2017.
Retrieved June 28, 2017. ^ (PDF). September 1997. (PDF) from the original on June 29, 2017. Retrieved June 29, 2017. ^ (PDF).
(PDF) from the original on June 29, 2017. Retrieved June 28, 2017. van Roon Chapter: 'Astable operation'.
van Roon, Chapter 'Monostable Mode'. (Using the 555 timer as a logic clock). ^ (PDF).
January 2015. (PDF) from the original on June 29, 2017. Retrieved June 28, 2017. ^ (PDF).
November 2012. (PDF) from the original on June 29, 2017. Retrieved June 29, 2017. ^ (PDF).
Retrieved June 29, 2017. (PDF). Custom Silicon Solutions. (PDF) from the original on June 29, 2017. Retrieved June 29, 2017. Retrieved June 30, 2017.
(PDF). (PDF) from the original on June 29, 2017. Retrieved June 29, 2017.
(PDF). January 2013.
(PDF) from the original on June 30, 2017. Retrieved June 29, 2017. From the original on January 9, 2013. Retrieved June 28, 2017. (see chapter 6). ^ (PDF).
October 2015. (PDF) from the original on June 29, 2017. Retrieved June 29, 2017. ^ (PDF). (PDF) from the original on June 29, 2017. Retrieved June 29, 2017.
^ (PDF). September 1997. (PDF) from the original on June 29, 2017.
Retrieved June 29, 2017. (PDF). X-REL Semiconductor. September 2013. (PDF) from the original on June 29, 2017.
Retrieved June 29, 2017. ^ (PDF).
Retrieved June 30, 2017. Creative Computing Video & Arcade Games. Retrieved June 30, 2017. (PDF).
January 1978. Retrieved June 30, 2017.
^. Retrieved June 30, 2017. ^ Eggebrecht, Lewis C. Interfacing to the IBM Personal Computer (1st ed.). Pp. 197–199.Further reading Books. 555 Timer Applications Sourcebook Experiments; 2nd Ed; Howard Berlin; BPB Publications; 218 pages; 2008;.
Engineer's Mini-Notebook – 555 Timer IC Circuits; 3rd Ed; III; Radio Shack; 33 pages; 1989; ASIN B000MN54A6. IC Timer Cookbook; 2nd Ed;; Sams Publishing; 384 pages; 1983;. 110 IC Timer Projects; Jules Gilder; Hayden; 115 pages; 1979;. IC 555 Projects; E.A. Parr; Bernard Babani Publishing; 144 pages; 1978;.Books with timer chapters. Volume VI - Experiments; Tony Kuphaldt; Open Book Project; 423 pages; 2010.
Designing Analog Chips; (inventor of 555 timer); Virtual Bookworm; 244 pages; 2005;. Timer, Op Amp, and Optoelectronic Circuits and Projects; III; Master Publishing; 128 pages; 2004;.
(Chapter 1). Linear LSI Data and Applications Manual;; 1250 pages; 1985. Analog Applications Manual;; 418 pages; 1979. TTL Cookbook;; Sams Publishing; 412 pages; 1974;.Datasheets. see links in section and 'References' section aboveExternal links Wikimedia Commons has media related to.