TCA9555:TCA9555 I/O limit current

Part Number: TCA9555



  • User,

    We can try and use Google translate to address this thread, but is it possible for you to post in English to make it a bit easier for our experts to support?

    From Google translate:

    When using with a power supply voltage of 3.3V, understand the maximum 10mA described in the data sheet, and is the current value that can be output from one terminal correct?
    Is it correct to understand that the total output current of the terminal is 200mA?

    Can you point out where the 10mA you are referencing is in the datasheet?


    Eric Hackett
  • 申し訳ありませんが、私は理解しているクロムを持っていました。
    7.5 電気特性
    (2) に従って、各 I/O は外部的に最大 25 mA に制限され、各 8 進数 (P07~ P00 および P17–P10) は
    、デバイスの合計 200 mA の場合、最大電流 100 mAに制限する必要があります。
    (3) すべてのI/Oが供給する合計電流は、160 mA(P07-P00の場合は80 mA、P17-P10の場合は80 mA)に制限されている必要があります。

    25mAです ~最大出力電流は160mA全端子ですよね?

  • 申し訳ありませんが、私は理解しているクロムを持っていました。


    (3)I/Oの値下、160 mA(P07-P00は、80mA、P17-P10)は、200mAを下します。



  • 私が読んだのは7.5章のIOLです。 Low level outputの部分です。






  • I'm sorry I made a mistake and posted in Japanese many times.

    10mA is Chapter 7.5 of the data sheet. But I realized I was wrong.

    Note (2) (3) in Chapter 7.5 states as follows.

    (2) The current limit of each terminal is 25mA

    (3) The current limit of all terminals is 160mA

    Is the above understanding correct?

  • Hello,

    The notes in 7.5 are talking about are two different things.

    "(2) Each I/O must be externally limited to a maximum of 25 mA, and each octal (P07–P00 and P17–P10) must be limited to a maximum
    current of 100 mA, for a device total of 200 mA."

    This is a limit on current flowing into the device. So this means that the current flowing into P07-P00 and P17-P10 must be limited to 100 mA each or 200 mA total.

    "(3) The total current sourced by all I/Os must be limited to 160 mA (80 mA for P07–P00 and 80 mA for P17–P10)."

    This is a limit on current flowing out of this device. This means that the current flowing out of P07-P00 and P17-P10 must be limited to 80mA each or 160 mA total.

    Let me know if this makes sense or if you have any further questions.



  • あなたの答えをありがとう。 私が確認したいのは、デバイスから流れ出る電流なので、私はノート(3)が答えであることを理解しています。 1端子デバイスから流れ出る電流に制限はありますか?

  • 回答ありがとうございます。

  • User,

    Again, if you can post in English that would be very helpful.

    "Thank you for your answer. I understand that note (3) is the answer because what I want to see is the current flowing out of the device. Is there a limit to the current flowing out of the 1-terminal device?"


    Eric Hackett

  • sorry I postponed japanese.

    I want to know current limited out of device each terminal.Is there a limit for each terminal?

  • Hello,

    The absolute maximum current limit for each P port pin is +/- 50 mA. The output current should be limited so that you do not exceed that current. You can place a series 100 ohm resistor and this would limit the short circuit current to below the maximum rating. It is also recommended that each 8-port octal (P07-P00 or P17-P10) does not exceed 80 mA each or 160 mA total. This means that you can't have every single P port drawing 49 mA of current because you could damage the device.

    As long as you follow those rules you won't damage the device. Let me know if you have any additional questions.