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TPS62262-Q1: Missing spec in datasheet for Ton / Toff timing

Josef Warta
Expert 4040 points
Part Number: TPS62262-Q1

Hello Team,

do we have specification for Ton and Toff with min/max spec?

Many Thanks

Josef

  • 0
    TI__Expert 3465 points
    Hello Josef,

    Let me clarigy a couple of points:
    -min Toff is zero, since this device can support 100% mode. As a consequence also max Ton is infinite.
    -max Toff also does not make much sense, since it's a Fixed freq operation.
    -min Ton is not specified. Anywat but one can go with Vout as low as Vref=0.6 V and calculate Ton@ Voutmin=0.6/5/(2.25*10^6)=53.3ns.
  • 0 in reply to Emmanuel Granatello
    Prodigy 100 points

    Hello Emmanuel,

    I think Josef meant the turn-on and turn-off times, not the on state and off state durations.

    Thanks,

    Hachim                                                                                                                                                                                                                                                                                                                                                    

  • 0 in reply to Hachim Hjira
    TI__Expert 3465 points
    Hello Hachim,

    got it. In that case there is just a typical start-up time (end of page 3) because it strongly depends on the passives. Indeed that spec is defined for "VIN = EN = 3.6V. External components CIN = 4.7μF 0603, COUT = 10μF 0603, L = 2.2μH".

    For the shut-down time, the situation is even more unpredictable since it depends on the load condition, on top of those parameters above.
  • 0 in reply to Emmanuel Granatello
    Prodigy 100 points

    Hello Emmanuel,

    Understood, but is there any formula to calculate these two parameters for a specific condition?

    Thank you,

    Hachim

  • 0 in reply to Hachim Hjira
    TI__Expert 3465 points

    Hello Hachim,

    sorry for this late answer.

    Could you give me your application Operating condition for helping you out on this question?

  • 0 in reply to Emmanuel Granatello
    Prodigy 100 points

    Hello Emmanuel,

    Thank you,

    Hachim

  • 0 in reply to Hachim Hjira
    TI__Expert 3465 points
    Hello Hachim,

    Unfortunately there is no formula that can be applied to calculate min-max turn-on time. The only information available is that there is a startup time (typ 500us) plus a ramp-up time (typ 250us).

    Regarding the turn-off time, you can estimate it taking into account the DS parameter Ilkg. You can consider indeed it is circa 5*RC, where C is the output capacitance and R is an estimation of the off resistance of the low side switch (3.6V/0.1uA, circa 36 Mohm).