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SN74LV123A: Tw(Output Pulse Duration) at Ta= -30C ->0C -> 25C

Tao_2199
Genius 5770 points
Part Number: SN74LV123A

Hello,

 

Regarding to the Tw(Output Pulse Duration Q/_Q) on SN74LV123A, my customer is asking following question.

･When temperature(Ta) is changed to Ta=-30C ->0C -> 25C,how is Tw changed?

(Supposing that the external capacitor and resistor are not affected to temperature..)

 

(Question)

(1) I will refer Tw timing at Ta=25C /Ta=-40 - 125C in switching characteristics(datasheet page 7/8).

 For example, according to datasheet (page 7),

(Cext=0.01uF,Rext=10Kohm)

Tw: 100us (typ) at Ta=25C   , Tw: 90us(min)/110us(max) at Ta= -40C to 125C

So when Ta is changed to Ta= -30C ->0C -> 25C, Tw will vary between 90us and 100us.

My understanding is correct?

 

(2) Or should I need to refer following application curve?

(Datasheet page 17, Figure 15. variations in Output Pulse )

I couldn't make clear that how it has the relation between above curve and the Tw of the switching characteristics(datasheet page 7/8).

Could you please give some advice or commnet?

 

Regards,

Tao2199

  • 0
    TI__Guru 62250 points
    Hi Tao ,

    your understanding of the limits is right. we can guarantee the pulse width to vary between 90uS to 110uS for -40 to 125C temp range. Since your application use case is within the temp range , this is applicable.
    The typical curves are collected in the lab and hence they are observed values .The curves and the spec table should align closely.
    The 90 to 110us is ~20% variation which is worse than the graph shown as 8% in absolute terms(-2% to 6%) .they are again not similar comparison though for diff R and C values.