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LM3481-Q1: about LM3481 no load input current

Part Number: LM3481-Q1
Other Parts Discussed in Thread: LM3481, LMR33630, LM5155

Hi TI,

I am considering to use LM3481 as pre-boost in our infotainment system, and I want it to be always enabled. I see that the datasheet only list typical supply current with switching, which is 3.7mA.

My question is, what's LM3481 no load input current? I see from datasheet that is has OVP, but I don't know during light load and OVP occurs, does LM3481 shut down and consumes little current?

Thank you and happy new year.

  • Hi Baoqian,

    Thank you for considering the LM3481. The no load Iq can be up to 5mA max in the worst case.

    Here I would strongly recommend the LM5150 which was specially designed for applications like the infotainment system as the preboost, and it consumes little power when the battery voltage is in good condition.  Basically it stays in sleep mode, only waking up when Vout is drop off a threshold (4 voltage level to program) to maintain the output voltage above a certain level.  Its no load Iq is less than 15uA, much lower than the LM3481.  Its sister part is LM51501, pin-to-pin compatible but having four different output voltage settings. 

    Thanks,

    Youhao Xi, Applications Engineering.

  • Hi Youhao,

    Thank you, I see LM5150 before.

    In our infotainment system, there's FM LNA and camera that needs about 12V. Even if I use LM51501, which has 11.5V boost output, I still need to use post buck to step down the voltage, because there will be high voltage transient in automotive battery. But the drop out voltage for Vin and Vout is very low. I mean maybe my camera can operate under 9V, 11.5V Vin and 9V Vout still means high duty cycle for buck converter. I use LM3481 to boost to 16V and LMR33630 to step down to 11V right now.

    So for lower current boost, I can use LM5155, or any other ideas?

    Happy new year.

  • Hi Boqian,

    Happy New Year to you, too! 

    Thank you for the clarification. Now I see why you cannot use the LM5150/501.  You are right that the LM5155 is a better part than LM3481 to consider.   Please let us know if we can be further assistance.

    Best Regards,

    Youhao