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LM2903-Q1: Saturation voltage

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Replies: 4

Views: 95

Part Number: LM2903-Q1

Hi; Team,

My customer had designed their application to use at Iol=8mA.

According to datasheet, Figure-5(Output Low voltage vs Output current),  We can know the typical VOL=about 0.3V_typ at 8mA.

At worst case, what should the maximum value of the output saturation voltage at 8 mA be estimated?

(Customer would like to keep <0.7v?)

If you have any VOL data(avg, std-dev) at around 8mA over temperature range on some lots and share it with me, It will better.

Regards,

H.Someno  

  • Hidekazu-san,

    We do not have distribution data for 8mA, just the 4mA datasheet production spec.

    The char data that was taken was used to create the Io vs Vo graph in the datasheet.

    The problem is that 8mA is on the knee of the current limit area - so that will add some variability, so we cannot extrapolate from the 4mA values.

    Since this is an "uncontrolled" (untrimmed) parameter, the variation can be as high as 30% between lots.

    The over temp spec is 700mV at 4mA, so it would be much worse at 8mA.

    Have they considered the new & improved LM2903B-Q1 version? It has a slightly higher current limit, so the 8mA is further away from the current limit knee, and lower overall saturation.

    Regards,

    Paul Grohe

    TI Comparators (CMPS) Applications Group

  • Hi Hidekazu,

    I would decrease Iol to 4mA, if possible.

    Kai

  • In reply to kai klaas69:

    Kai's suggestion is reasonable.  Unless you especially concerned with the rise and fall time of the output transition, increasing your pullup resistor value will improve the noise margin of your output logic levels.

    Chuck

  • In reply to Chuck Sins:

    We have not seen any response on this thread for a while, so I will be closing the thread.

    If you need further assistance, please feel free to reopen or start a new post.

    Thanks

    Chuck

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