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TPS54329: Vin close to min

Viktorija Cecil
Mastermind 18181 points
Part Number: TPS54329

Team, 

Customer is using TPS54329 in their system, and powering it up with 12V. They would like to improve efficiency, and ease the layout by using 3.3V or 5V Vin, however datasheet says >4.5V is needed, and customer's experience is if the device’s Vin is near its min value, it will create so much noise and other switching problems that are hard to pin point. 

I would appreciate your inputs. 

Thanks

Viktorija

  • 0
    TI__Prodigy 450 points

    Hi Viktorija,

    What's the Vout and iload for the customer?

    Due to the 650kHz fsw and minimum off time requirement, there is a absolute maximum duty cycle limitation to be considered here when Vin is low like at 5V.  And, if the duty cycle is close to the max limit, the transient response will be degraded due to the lack of headroom of duty cycle. 

    Correct, you may not use at Vin=3.3V according to datasheet requirement (Vin>4.5V).  The typical under voltage lock out is 3.75V for this device which is generated by LDO.  

    regards,

    jenson