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TL7705A: Externally Adjustable Pulse Duration using large CT

Dice-K
Mastermind 6827 points
Part Number: TL7705A
Other Parts Discussed in Thread: TL7705B

Hello.

Can I set a delay of 1s by using a large capacitor such as 70~80μF for CT?

1.3 * 10000 * 77μF = 1s

Similarly, in the case of TL7705B,
Can I set a delay of 1s by using a large capacitor such as 35~40μF for CT?

2.6 * 10000 * 39μF = 1s

Regards,
Dice-K

  • 0
    Guru 140200 points
    Hi Dice-K,

    earlier datasheets recommended a maximum Ct ot 10µF. But even up to 100µF seem to be possible:

    www.ti.com/lit/an/slvae04/slvae04.pdf

    Kai
  • 0
    TI__Genius 12630 points

    Dice-K,

    You can use larger capacitors but as you increase capacitance, the range of delay widens. Keep in mind that a 10% tolerance on a large value is much wider than 10% tolerance on a small value so the delay won't be as accurate. I recommend testing the capacitor and checking that the delay is what you want.

    -Michael