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LMC555 Discharge current/time

cafain
Mastermind 6835 points

Other Parts Discussed in Thread: LMC555

Hi,

LMC555 Discharge current/discharge time of Discharge terminal(7-pin)

!!! No Discharge Leakage current !!!

There is a schematic diagram in the LMC555 Data sheet (SNAS558K) page3.

We will ask about DISCHARGE terminal. The user of the design, use R = 10kΩ, V + = 5V, the C = 47μF.

1) Inside of Discharge terminal, What is the maximum value of the sink current of the open collector transistor (discharge current of the capacitor)? 　　

    (Is it possible to allow the discharge current of 47uF)

2) What is the discharge time of Discharge terminal.   

   (What is the discharge time of 47uF)

Best regards

  • 0
    TI__Genius 10320 points
    Hi Cafain,
    I've forwarded your query to the applications engineer most familiar with this device.
    Thanks for your patience!
    Gabe
  • 0 in reply to Gabe Ayala
    Mastermind 6835 points

    Hi,

    I am waiting for the answer.
    Best regards

  • 0 in reply to cafain
    Guru 10200 points

    Hi All,

    Who is supporting this question? I have same question, too.

    On datasheet P.8 Figure 3, our customer condition is Vs = 5V, Ra = 10k and C = 47uF.

    1) What is the maximum value of the sink current of DISCHARGE pin? And what is the discharge resistance value of DISCHARGE pin? 　　

        (Is it possible to flow the discharge current into device from 47uF capacitor?)

    2) What is the discharge time of DISCHARGE pin at C=47uF condition?

        (I think we can judge about this if we have discharge current value information)

    Best Regards,

    Kohei Sasaki

  • 0 in reply to K. Sasaki14
    TI__Genius 16890 points
    Hello,

    The discharge current is limited by the resistance of the internal discharge transistor. Some values are shown in the datasheet on page 5 "Discharge Saturation Voltage". With Vs at 5V and the discharge current at 10mA the transistor will have a resistance of 30 ohms.

    Mike
  • 0 in reply to Michael Stout
    Mastermind 6835 points

    Tank you Mike.

    Maximum sink current of the device inside of Discharge transistor Are you "Ie =10mA" ?

    (Ie:Discharge-transister-emitter current)

    The maximum single current is defined as the value that satisfies the specification.

    (Not in the Absolute Maximum Ratings)

    Best regards