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LMC555: 50% Duty Cycle Oscillator

Part Number: LMC555
Other Parts Discussed in Thread: TLC555

Hi Ron-san,

My customer is considering to use LMC555 for the 50% duty cycle oscillator by referring to your below thread.
  - [FAQ] How do I design a-stable timer, oscillator, circuits using LMC555, TLC555, LM555, NA555, NE555, SA555, or SE555?

Since they want to calculate the tolerance of the 50% duty cycle, they want to know min/typ/max specification of the following parameters of the LMC555CMX/NOPB. 
 - Output driver:
       - ROH: Min= , Typ=, Max=
       - ROL: Min= , TYp= , Max= 
 - Output delay:
       - The output low to high time delay: tPLH: Min= , Typ= , Max= 
       - The output high to low time delay: tPHL: Min=, Typ=, Max= 

Thank you.

Best Regards,

Koshi Ninomiya

  • Hi Ninomiya-san,

    Unfortunately we do not have data on the propagation delay of the LMC555. However, these delays have a very small effect at low frequencies. I have some sample data I can share with you on the ROH and ROL. There are no guaranteed min, typ, and max values as these were not tested for. The ROH and ROL are voltage supply and temperature dependent. See below for the sample data graphs. Use R= V/I at the temperature and supply you are interested in. 

    The TLC555 is also a CMOS timer. The datasheet of this timer does provide graphs for Propagation Delay vs Control Voltage on page 13, and Output Low/High Resistance vs Temperature on page 12.

    Best,

    Katlynne Jones