TMS570LS1224: Supply current needed to power this device

Leslie Marquez

Hello,

I’m trying to select the current rating for the LDOs that will power the MCU (1.2V and 3.3V). What is the maximum current that I should consider for this LDO selection? I’m designing 2 versions of the board:

MCU running UART or SPI --> For this, I want to use LDOs
MCU running code to translate between CAN and UART and viceversa. --> For this, I’ll likely use a buck converter + LDOs.

I did review the supply current spec in the MCU datasheet, but it wasn't clear to me which spec to consider for these cases above.

Best regards,

Leslie

over 5 years ago

0 Sunil Oak over 5 years ago

TI__Mastermind 49120 points

Hi Leslie,

You should use the max current specifications for sizing the LDOs you need to supply the part. There are typically two separate supplies required, 1.26 V nominal +/- 10% for the core logic (digital, PLL), and 3.3 V nominal +/- 10% for I/Os, ADC, Flash Pump.

Regards, Sunil

0 Leslie Marquez over 5 years ago in reply to Sunil Oak

TI__Genius 9461 points

Hi Sunil,

Thanks. Is 1.26V a typo? the datasheet says 1.2V typical.

Regards,

Leslie

0 Sunil Oak over 5 years ago in reply to Leslie Marquez

TI__Mastermind 49120 points

Hi Leslie,

1.2V is typical sure. Then you would need a supply with tolerances of -5% to +10%. Usually LDOs have an equal +/- tolerance, so you either limit the max core supply possible, or set the nominal supply point a bit higher.

Please also note the requirements for driving power-on-reset input with respect to the supplies.

Regards, Sunil

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TMS570LS1224: Supply current needed to power this device