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Anybody used the TC4432 (30v buffer)

Discussion in 'Electronic Basics' started by lerameur, Sep 18, 2008.

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  1. lerameur

    lerameur Guest

    Hi,

    I am trying to use the TC4432. I am doing the exact circuit of page 7
    below. My Vdd is at 1v, and my input is coming from a pic chip running
    at 10khz 60% duty cycle.

    http://www.datasheetcatalog.com/datasheets_pdf/T/C/4/4/TC4432.shtml
    page 7 of microchip

    What I am getting at the output is oscillation between 10v low to 12v
    high. The frequency is good, but it is not coming down to zero volt
    like expected. Any body used this chip and can show me a working
    circuit or have any ideas why that is?

    thanks

    K
     
  2. lerameur

    lerameur Guest



    TYPO
    :I am trying to use the TC4432. I am doing the exact circuit of page 7
    below. My Vdd is at -- 12v --- and my input is coming from a
    pic chip running
    at 10khz 60% duty cycle.
     
  3. Vdd is 1v? The minimum is 4.5V. I'm guessing you really meant
    something else.

    The Vdd must be between 4.5 and 30V, and the logic input switches at
    0.8V and 2.4V. The output is 'open collector', meaning that you need
    to pull it up to Vdd using a resistor in order to see any action.

    Watch out for a floating UVLock pin.

    3.3 Lockout Disable (LOCK DIS)
    The lockout pin enables/disables the undervoltage
    lock-out feature of the device. If undervoltage lockout is
    desired (output is not enabled until the bias voltage
    reaches 8.4V (typical) on the rising edge and is disabled
    when the bias voltage reaches 7.7V (typical) on
    the falling edge), the lockout pin should be left floating.
    If operation below 7V is desired, the lockout pin should
    be tied to ground.

    Regards,
    Bob Monsen
     
  4. Jamie

    Jamie Guest

    Maybe I've missed something here, the spec's state that Vdd starts at
    4.5 V up to 30, You stated 1 volt? Maybe this is a clerical error and
    should be like 10 volts ?

    Also, the output Z is rated at 7 ohms, you must account for that as
    it will influence the drive to the fet.

    Have you placed a series R of around 10 or so ohms driving the
    gate? If so, you could examine the signal via a scope and test for
    a drop. It's very possible the driver isn't able to sink the output
    enough.

    You should try to test the output of the driver with no load or very
    little load to determine the problem here.

    It's possible the capacitance on the gate is excessive for the
    driver to get the response you're looking for.



    http://webpages.charter.net/jamie_5"
     
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