NE556 Dual Timer/Oscillator
Data sheet
Similar to: LM556-SE556C-MC3453-MC3556-NTE978-ECG978
by Tony van Roon, CET
The 556 Dual Monolithic timing circuit is a highly stable controller capable of producing accurate time delays, or oscillation. The 556 is simply a dual 555. Timing is provided by an external resistor and capacitor for each timing function. The two timers operate independently of each other sharing only Vcc and Ground. The circuit may be triggered and reset on falling waveforms, and the output structure may source or sink up to 200 mA.

Features:
  • The NE556/SE556 timers can be directly replaced by the CMOS td3
    types MC3456/MC3556.
  • Timing from microseconds to hours.
  • Supply voltage from +4.5V (min) to +18V (max).
  • Replaces two 555 timers.
  • Maximum operating frequency greater than 500Khz.
  • Operates in both astable and monostable modes.
  • High output current.
  • Adjustable duty-cycle.
  • TTL compatible.
  • Temperature stability of 0.005% per °C.
  • Rise and Fall times of output is 100nS typical.
  • SE556 type MIL STD 883A, B, C is available.

    Some Applications:
  • Precision Timing.
  • Pulse shaping.td2
  • Pulse generation.
  • Sequential timing.
  • Timedelay generation.
  • Pulse width modulation.
  • Pulse position modulation.
  • Missing Pulse Detector.
  • Tone burst generator.
  • Appliance timing.
  • Traffic light control.
  • Touch tone decoder.

    Absolute Maximum Ratings:
  • Supply voltage for SE556 +18 volt. For NE556 & SE556C +16 volt.
  • Discharge current (pin 7) is 200mA.
  • Power dissipation 600 milliWatts.
  • Operating temperature range for NE556 0 to 70 °C, for SE556 & SE556C -55 to -125 °C.
  • Storage temperature range from -65 to -150 °C.td1
  • Lead temperature (soldering, up to 60 sec) +300 °C.

    Notes:
  • Supply current when output high typically 1mA or less.
  • Tested at Vcc=5V and Vcc=15V.
  • This will determine the maximum value of Ra+Rb, for 15V operation, the max total
    R = 10 megohm, and for 5V operation, the max total of R = 3.4 megohm.
  • Specified with trigger input high.
  • Time measured from a positive going input pulse from 0 to 0.8 x Vcc into the threshold
    to the drop from high to low of the output. Trigger is tied to treshold.
  • Available in D, F, N, plastic packages. 'D' suffix being the SO-8 surface mount type.

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    Copyright © Tony van Roon, CET