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ULN2003AI Vin range at Recommended Operating Condition

Other Parts Discussed in Thread: ULN2003AI

Hi,

We used Toshiba's TD62083AFG for a long time, but recently noticed that this product is discontinued soon.

So I found the TI's ULN2803ADWR and ULN2003AI as one of the replacement devices.

at ULN2803A datasheet, the recommaned Vin spec is 0 ~ 5V, so we cannot use this item,

but ULN2003AI datasheet, there is no comment about recommended Vin spec.

I found the absolute maximum range as up to 30V, but I want to know the Recommended Operating Condition of input voltage of ULN2003AI.

thanks,

  • Hello TI,
    I'm still waiting your response.
    thanks,
  • These devices are designed to be connected directly to some logic-level device.

    What input voltage do you actually need?

  • Hello TS,

    The ULN2803 is a drop in pin to pin replacement with the TD62803 device to which you are referring.
    If you are looking to replace the TD62803, the ULN2803 will be suitable.
    The recommended input voltage in the recommended operating conditions is misleading, this device can be used with 3.3V logic as well as 2.5V logic if that is what you are looking to use it with.

    Thank you very much for considering to use our device. I would be very happy to help in support further in whatever way I can. Please let me know if you have further questions.

    Best,
    Michael
  • Hello Michael,

    thanks for your kind answer.
    I undersood that these devices are designed to be connected directly to some logic-level device.
    Actually we used TD62803 at 24V signal line in front of relay.
    The measurement maximum voltage is 27~28V.
    So I'd like to know the the recommaned Vin MAXIMUM spec of ULN2803 .
  • Hello TS,

    I apologize for the delay in response, as there was a US holiday last Thursday and Friday.
    The specification for the recommended input for the ULN2803 is misleading. The range of acceptable input voltages is much wider.

    The maximum input voltage is 30V, as described in the absolute maximum. Since the maximum measured voltage is within the 30V specification for the ULN2803, then the device should be fine. If you refer to the functional block diagram in the ULN2803A datasheet, it shows the internal structure of the device. The internal transistors are rated to handle if the input is 30V. So up to 28V input would be acceptable for the device. The only drawback is that you will have additional current to ground, which will be consuming additional power.

    It would also be acceptable to add series resistance at the input of the ULN2803 to reduce voltage seen at the transistor as well as decrease the power consumption.

    I hope this is clear. Please let me know if you have additional questions or concerns.

    Best,
    Michael