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TPS53219A: VDD Pin and VDRV pin contact

Louis Lo
Intellectual 1945 points
Part Number: TPS53219A

Hi  

Customer have two question about TPS53219A setting and could you help to check them ,thanks. 

1. VDD Pin suggest connected to which voltage level if 5V cannot be used, use  ADAPTER , 20V is available ?
2. Whether the VDRV pin can only be connected to the internal LDO, if external 5V is possible ?

  • 0
    TI__Guru 50515 points
    Louis Lo said:
    1. VDD Pin suggest connected to which voltage level if 5V cannot be used, use  ADAPTER , 20V is available ?

    If external 5V is available, VDD can be powered from 5V.

    If an external 5V is used for VDD, there is some benefit to connecting the external 5V to both VDD and VREG to reduce the internal LDO drop from VDD to VREG.

    VDD can be externally powered from VDD.  The larger voltage drop from VDD to VREG will increase the internal power dissipation of the TPS53219A.

    Louis Lo said:
    2. Whether the VDRV pin can only be connected to the internal LDO, if external 5V is possible ?

    VDRV can be connected to an external 5V supply separate from VREG.  VDRV should not be powered when VREG is not powered, so this can present a sequencing issue if the external 5V provided to VDRV can be higher than the source for VDD.

  • 0 in reply to Peter James Miller
    TI__Intellectual 1945 points

    HI Peter 

    I have one more question need confirm when customer VDD contact to 5V that is input source for internal LDO to Vreg so the Vreg will be 5V too ?  

  • 0 in reply to Louis Lo
    TI__Guru 50515 points

     

    Yes, VDD is the input source for the LDO, as shown in the block-diagram from the datasheet (Section 7.2 on page 11)

    If powering VDD with 5V, it is recommended that VREG is also powered by the same 5V.  VDD, VREG, and VDRV will all still need their own local bypass capacitors at their pins to limit noise on the pins.

    To further limit driver switching noise from the sensitive analog signals powered by VREG, you can power VDRV directly from the external 5V supply and place a 10Ω resistor between VDRV and VDD/VREG.