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LMR62014: Output Power Capabilities at 15V Output Voltage

Part Number: LMR62014
Other Parts Discussed in Thread: LM5158, LM2621

Hello,

I would like to know if the LMR62014 will be appropriate for my application.

Output Voltage: 14V/15V

Input Voltage Range: 5.5V - 12V (actual range is 6V-12V, but 5.5 is the worst case scenario)

Load Current: 400mA

My initial computation showed it near 500mA max load current and the figure 22 in the datasheet might suggest it would be between 400-600mA? Is this accurate?

Will 400mA be too close to the absolute maximum load current for these set of parameters?

On Another Note: If my load current is doubled to 800mA. What alternative part to the LMR62014 would be recommended?

Thanks,

Deniel

  • Hi Deniel,

    Yes, the figure's data is right, but the max load current is related to inductor peak current. When inductor peak current is lower than IC's peak current limit (fig 21), it can work normally. The figure's data keep some margin so the max load current is about 400-600mA. I think LMR62014 can work for your application, please also select larger inductor (10uH or 22uH) to realize smaller inductor current ripple.

    For 800mA, the input average current will be up to 2.5A and peak current will be 3A. LM5158 is recommended for this application.

  • Hello Eric,

    Thanks for the response. When you mentioned "The figure's data keep some margin so the max load current is about 400-600mA", will we be running into thermal issues or max current capability issues, If our actual load current is around 350-400mA? (Given that we already selected a larger inductor of 10 or 22uH). Are there more layout/thermal considerations we need to take into account given our larger power output? (14/15V at 400mA). We are currently basing our layout on the LMR62014 Demo Board: https://www.ti.com/lit/ug/snva500b/snva500b.pdf

    What types of test would you suggest we do to ensure our design (schematic and PCB layout) will not be near failing state due to the PCB layout/thermal issue or due to the current and voltage we are giving to the Load?

    Regarding the 800mA application, the LM5158 is not available in the TI inventory and the cost higher than what we are currently considering. If our output voltage was fixed to 14V instead of 15, I would like to know if we can use any of these ICs listed below?

    These ICs do not have any data for our application 14V output and output current of 800mA

    1. https://www.ti.com/product/LM2623-Q1

    2. https://www.ti.com/product/LM2623

    3. https://www.ti.com/product/LM2621

    4. https://www.ti.com/product/LM2731

     

    Thanks,

    Deniel

  • Hi Deniel,

    I think there will be no thermal issues if you follow the user guide of demo board and layout hints in datasheet. Please remember min loop area of SW-D1-Cout-GND pin and SW node area. 350mA-400mA is okay in this situation. please also use wide route to decrease resistance on power route such as Vin and Vout

    Just make sure the inductor peak current is within current limit is okay. Layout will effect Chip's performance such as ripple.

    I don't think these chips can output 800mA at 14V, maybe LM2621 can output 500~mA, but 800mA will hit all these chip's current limit.