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LM3671: Vin - 4.3V to 3.3V Vout - 3.3V , Iq-16uA

Ankush
Prodigy 220 points
Part Number: LM3671
Other Parts Discussed in Thread: TPS62840

I am using LM3671 IC for my Li-ion battery operated device because its LOW Iq current. But my scary part is Li-ion battery's input. Li-ion battery's voltage range is 4.3V to 3.3V, then what will be the OUTPUT at 3.3V Input of IC.

1. What is drop out voltage of IC ( at 200mA Current Consumption of device ).

  • 0
    TI__Genius 13460 points

    Hi Bhagyesh,

    The description below table 6.4 has a detail explanation of the input voltage requirement for certain range of output. The device input voltage should be higher than the output voltage and if it is not high enough buck converter will not regulate the output voltage and you might get the strange performance. 

    The voltage dropout can be calculated through the power dissipation and efficiency of the device and this app note can help out:  http://www.ti.com/lit/an/slva390/slva390.pdf  

    est regards,

    Tanvee

  • 0 in reply to Tanvee
    Prodigy 220 points

    Sorry, but still my question not resolved. 

    Kindly suggest similar IC, like LM3671. What will be the output at 3.4V input of LM3671 (Output current 200mA - peak current)?

  • 0 in reply to Ankush
    TI__Genius 13460 points

    Hi Bhagyesh,

    LM3671 device will regulate 3.3V for 0.2A load till the input voltage is 3.5V. Lower than that it will not regulate the output voltage. The conditions can be checked on webebnch model.

    You can take a look for the TPS62840 device which is designed for low Iq applications. 

    Best regards,

    Tanvee

  • 0 in reply to Tanvee
    Prodigy 220 points

    Ok. Thank You For Your Reply!

    What will be the output of TPS62840  at 3.35V input (Output current 230mA - peak current)?

    My lithium-ion battery's output voltage range is 3.3V to 4.3V, kindly suggest suitable IC, who can support battery range(Low dropout Voltage) as well as low Iq.

    Expected output voltage is 3.1/3.2V/3.3V (Not less than 3.1V and not more than 3.3V).

  • 0 in reply to Ankush
    TI__Genius 13460 points

    Hi,

    TPS62840 has low Iq which will increase the battery life but If the main concern is output voltage 3.3V on 3.4input than TPS6282x is good for application which has lower internal power resistance and Iq is also better than LM3671.

    Best regards,

    Tanvee