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LM5118-Q1: LM5118-q1

Part Number: LM5118-Q1
Other Parts Discussed in Thread: LM5118, LM5141, PMP15041, TPS54360

Hi Team,

I am using LM5118-Q1 BUCK-BOOST controller.In NO load condition its will take 5 to 7mA.i need Operating Quiescent Current is less than 500uA.kindly give your valuable feed back as soon as possible

  • Hi Govenhan,

    Thanks for reaching out with your questions.

    Unfortunately the LM5118 with draw 4.5mA typically (see the electrical characteristics table in the datasheet) when the UVLO pin is pulled high. There is no way to reduce this current. What are your application specifications? I can help find a part with lower operating current.


  • Dear Garrett,


    As this power controller IC is meant for automotive applications we expected a very low “no load“ current in micro amps (not in shutdown mode) with Still providing output voltage.

    The sleep mode current requirement for our entire cluster is itself < 1mA. We have managed our other loads in cluster to draw less current in sleep mode.

    But the power IC we are not able to control. Also we cannot use the shutdown mode as our MCU needs to be powered during sleep mode.

    Please suggest a way to minimize the no load current in the LM5118-Q1 power IC to less than 50 uA (for 3 to 60V input voltage range), still delivering output voltage of 7V or suggest a different part that meets our requirement.

    I have detailed our requirements for the switch mode power supply as below for your reference.

    Input voltage requirement: 3 to 60V

    No load current should be <50 uA for (3 to 60V input voltage range), still delivering output voltage of 7V.
    The power supply should be able to deliver constant 7V and 3A at 3V input for cranking condition in vehicle.
    Vin nominal: 13.5V and 27V
    Output voltage: adjustable (7.0V to be used)
    Maximum continuous Output current : 3.5A
    Nominal output current: 1A
    Operating temperature range: -40 to 95 degC
    Automotive grade needed
    Mounting type: SMD
    Component road map: min 10 years from now

    Component has to withstand:
    1. ISO 7637 pulse 1, 2A,2b,3a,3b with level-4

    2. ISO 16750-2 load dump pulse
    12V system: Us - 101 V,  Ri - 0.5 ohm, td - 400 ms
    24V system: Us - 202 V,  Ri - 1 ohm, td - 350 ms

    3. Power supply design to be compatible with the EMC
    CISPR 25, Class 4

    4. Radiated emission:
    Test method: As per ISO 13766
    Test voltage:13.5 =+/- 0.5 V
    Meter operating range : Mid scale
    Frequency range: 30 to 1000 MHz (1 GHz)
    Test method & condition: Narrowband & Broad band emissions for ESA test

    Frequency: 30 to 75 MHz
    Narrowband emissions reference limit(dBu V/m) peak: 54
    Broadband emissions reference limit(dBu V/m) peak: 64

    Frequency: 75 to 400 MHz
    Narrowband emissions reference limit(dBu V/m) peak: 44 + 15.13 log (freq in MHz/75)
    Broadband emissions reference limit(dBu V/m) peak: 54 + 15.13 log (freq in MHz/75) 

    Frequency: 400 to 1000 MHz
    Narrowband emissions reference limit(dBu V/m) peak: 55
    Broadband emissions reference limit(dBu V/m) peak: 65




  • Hi Govendhan,

    As mentioned before there is no way to decrease the operation current of the LM5118. When the UVLO pin is pulled high (regulated output voltage) the VIN pin is going to sink typically 4.5mA plus the current required to drive the external MOSFETs. Currently there is not a solution that meets the criteria of the application regarding the input current requirement.

    The best solution is going to be using the LM5150 as pre-boost plus the LM5141 as a buck. Please take a look at PMP15041.

    Please let me know if you have any questions.

  • Hi Garrett,

    Thanks for your reply. Can we check with LM5150 as pre-boost plus the TPS54360 as a buck

  • Hi
    The responsible engineer is out of office now. He will reply by 4/23.
    LM5150 supports <1mA. It is better to post your questions about TPS54360 performance separately to get the answer ASAP.
  • Dear EricLee,

    Thanks for your valuable feedback.