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Microcontroller core supply : LDO or SMPS ??

Govind K
Intellectual 510 points
Other Parts Discussed in Thread: F28M35H52C, TMS570LC4357, TPS62080, TPS62360, TLV62565, TPS62160

Hello ,

Till now i have worked on microcontrollers which has embedded voltage regulators (3.3V to 1.2V core supply) for example: F28M35H52C, TC1724 etc.. 

In my current project, i am using TMS570LC4357 controller which needs external 1.2V @ 1.1A current. 

Shall i use buck regulator (SMPS) ?? or LDO is an prefferable option. I am not sure which Topology meets the Core supply requirements (Like, output voltage ripple, transceint responce, etc...). 

Kindly suggest.

Thanks in advance,

Regards,

Govinda R K

  • 0
    TI__Guru**** 150650 points

    I would recommend a SMPS at that high current.  The LDO would get very hot and be inefficient.

    TPS62360 family is optimized for a core rail, if you need DVS, etc.  Otherwise, TPS62080 is a good option.

  • 0
    TI__Genius 16870 points

    Hi Govinda,

    You are going to want a buck or step down SMPS assuming that your VIN is higher than your VOUT, (3.3V in this case). This is because your efficiency would be poor with an LDO. The buck will give you much better efficiency.

    For noise sensitive loads, some like to use LDOs to reduce the ripple on the load input. Although, most likely a modern buck do fine with VOUT ripple performance for your application.

    Do you have more loads in your system? Possibly other voltages and etc.?

    We have a great line up of bucks and if you need multiple rails we have a great line up of PMICs, which are ICs with multiple bucks, LDOs, or other SMPSs integrated on the IC. These can same you time, cost and board area.

    For bucks I recommend looking at the TPS54xxx line up for high VIN voltages, possibly wall powered devices, and TPS62xxx for battery powered devices.

    For PMICs I recommend looking at the TPS65xxx line up.  

  • 0 in reply to Michael Green
    Intellectual 510 points

    Hello Mr. Michael Green,

    Thanks for information.

    Answering to your queries, Yes,  i have few other loads in my system as mentioned below.

    Input Voltage: 5V DC. Output Voltage-1: 3.3V @ 1.2A Max. Output Voltage-2: 1.2V @1.1A Max.

    3.3 Volts will be used for Controller's I/O supply, Flash pump supply and Other peripherals like  CAN Transceivers.

    1.2 Volts will be used as Controller core and PLL supply.

    Please suggest suitable PMIC. In-fact i have tried from my end, but couldn't find PMIC which has 1A LDO. May i missed somehow.. !

    Thanks in advance.

    Regards,

    Govind.

  • 0 in reply to Govind K
    TI__Guru**** 150650 points

    An LDO is not a possible choice with that much current.  You need 2 SMPSs.

    TPS62080 for both rails or TPS62360 for the core rail are best.  Converting each rail from the 5V input is most efficient.

  • 0 in reply to Chris Glaser
    Intellectual 510 points

    Hello Mr. Chris Glaser,

    I have gone through the data sheets. We are restricted use IC packages which supports manual soldering. 

    I would have mentioned this point im my query, really sorry for that. !!

    Request you to suggest another device simiallar to your recommended devices (core rail/rail for both).

    This is my final query. Kinldy answer.

    Thanks in advacnce.

    Regards,

    Govind.

  • 0 in reply to Govind K
    TI__Guru**** 150650 points

    A decent technician with a hot air gun should be able to solder either the SON or WCSP package.

    But if you need an old-school leaded package, we have TPS62160 in an MSOP which does 1A.  If you really need a little more than 1A, we have TLV62565/6.