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Original question:

CSD95420RCB: RE: CSD95420RCB Application information with Multiphase Controller TPS53659RSBR

CSD95420RCB: RE: Pins Comparison of CSD95420RCB and CSD95492QVM

Niranjan Kumar
Intellectual 285 points
Part Number: CSD95420RCB
Other Parts Discussed in Thread: CSD95495QVM, , TPS53659, CSD95492QVM, TPS562203

Tool/software:

Hi 

We used CSD95495QVM in our project design along with the TPS53659RSBR controller. However, the CSD95495QVM has only one year of lifecycle remaining, and TI recommends using CSD95420RCB as a replacement.

we are going to use CSD95420RCB, but we observed that there are VOS Pins are not present in the CSD95420RCB, so can you please suggest how we can sense out put voltage.

for your reference we have attached pin out image for CSD95495QVM and CSD95420RCB

Thanks

Niranjan

please look into this and respond asap?

  • 0
    TI__Expert 4345 points

    Hi,

    There is no VOS pin on CSD95420, as the device does not require output voltage sense.

    Since CSD95420 is a different pinout than CSD95495, there is no need to try and maintain the same output voltage sense connection. 

    Regards,

    Troy 

  • 0 in reply to Troy Johnson
    Intellectual 285 points

    Hi

    We have need some clarity then how to sense out voltage, we have checked data sheet and block diagram of CSD95420 but we don't understand how we can sense output voltage without VOS pin. so can you please help to understand this? 

    for your reference we have attached  CSD95420 block diagram from data sheet.

    Thanks,

    Niranjan

  • +1 in reply to Niranjan Kumar
    TI__Expert 4345 points

    Hi,

    CSD95420 does not sense output voltage, as its internal circuitry does not require it.

    The system PWM controller, TPS53659, will still have output voltage sense for control loop response and reporting via PMBus.

    Regards,

    Troy

  • 0 in reply to Troy Johnson
    Intellectual 285 points

    Hi, Thanks for your prompt reply

     We have also need some clarity about EN pin of CSD95420,we observed that there are EN/FCCM dual function Pins are present in the CSD95495. but there are FCCM pins are not present in CSD95420. so can you please clarify how we can use this always in FCCM mode.

    for your reference please find the attached image below. 

    Thanks

    Niranjan

  • 0 in reply to Niranjan Kumar
    TI__Expert 4345 points

    Hi,

    By default CSD95420 will operate in Forced Continuous Conduction Mode (FCCM), and it will only enter Discontinuous Conduction Mode (DCM) if it receives a specific PWM pattern, where the PWM goes from low to tri-state to high.

    The entry to, and exit from, DCM mode is described in the full datasheet for CSD95420, under section 7.2.5.

    If you want CSD95420 to always operate in FCCM, you only to ensure that the controller does not send the low-3T-high pattern. For TPS53659, set the option for DPS_DCM_EN to use CCM in 1-ph operation, if DPS is enabled, to ensure the controller does not attempt to enter DCM.

    Regards,

    Troy

  • 0 in reply to Troy Johnson
    Intellectual 285 points

    Hi Troy,

    We need some clarity regarding the load current for our application. Previously, we used the CSD95492QVM to support a 2A load current, but since this part is now NRND, TI has suggested using the CSD95420 as an alternative. However, we need confirmation on whether the CSD95420 is suitable for a 2A load current.

    Upon reviewing the datasheet of the CSD95420, we noticed that the power loss is approximately 1W at lower currents, whereas the CSD95492QVM has power losses below 0.5W under similar conditions.

    Could you please advise whether the CSD95420 is appropriate for applications requiring a low load current of around 2A, considering the higher power losses?

    for your reference we have attached image for both part number

    Thanks

    Niranjan

  • 0 in reply to Niranjan Kumar
    TI__Expert 4345 points

    Hi,

    I will check if any of our other devices are more appropriate for this low load current, and get back to you by this Thursday (5/29).

    Regards,

    Troy

  • 0 in reply to Troy Johnson
    Intellectual 285 points

    Hi Troy,

    Thanks for your response Looking forward to your next reply.

    Regards,

    Niranjan

  • 0 in reply to Niranjan Kumar
    TI__Expert 4345 points

    Hi,

    If you want to stay using a controller + power stage setup, such as using TPS53659 + power stages to run both a higher output current rail and the 2A rail, then the CSD95420 power stage is appropriate.

    If your primary concern is low current efficiency however, you may consider options for a standalone buck converter, such as TPS562203, that can provide higher light load efficiency.

    Regards,

    Troy