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ULQ2003A: Maximum Input Current @VI=5V

Yazhu Liu
Intellectual 1410 points
Part Number: ULQ2003A
Other Parts Discussed in Thread: TPL7407LA

Hi Team,

Do we have the maximum input current value of ULQ2003A @ VI=5V?

There's only max Ii @VI=3.85V in the datasheet.

Also, for VI=3.85V, Ii_max=1.35mA, is this 1.35mA the maximum limitation?

Please kindly comment on that.

Thanks.

Best Regards,

Livia

  • 0
    TI__Mastermind 32650 points

    Hi Livia,

    We do not have that information. This is not a limitation exactly as it is describing the input leakage when the output is left open. Please refer to figure 12 to see the testing setup. As this is a BJT device, the input current changes based on the output load current but since this is a Darlington pair, the input current is minimal. Please refer to Figure * to see the minimum output current vs input current. 

  • 0 in reply to Shreyas Dmello
    TI__Intellectual 1410 points

    Hi Shreyas,

    Thank you for the quick reply.

    Per my understanding, Figure 8 in the datasheet gives the illustration the needed input current value to support the corresponding output current, am I right?

    Also why the input current(0.65mA) for max output current(500mA) is even smaller than the Ii(leakage) input current(0.93mA TYP)?

    But customer would like to know if we have the maximum input current limitation for ULQ2003A, which won't cause damage to the device. Should I refer to Figure 6 for this value?

    Thanks.

    Best Regards,

    Livia

  • 0 in reply to Yazhu Liu
    TI__Mastermind 32650 points

    Hi Livia,

    Your understanding of Figure 8 is correct. As you can see, only small amounts on input current are required to support the entire working range of output current.

    The leakage spec shown is when the device is ON and there is no output connected. Due to the BJT structure of the device, I believe the path through the base to emitter can be quite leaky. Unfortunately, I believe the only way around this(if it is a concern) is to use a FET based device like TPL7407LA. Still, most MCUs should be able to supply up to 5mA so it may not be a concern.

    There is no true input current limitation. The input current pulled will be a function of the load current flowing through the device. If the load current is in spec, then there is no concern for the input current being supplied.