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Using tps65023B with AM35xx

Mugen
Intellectual 280 points
Other Parts Discussed in Thread: TPS65023B, TPS65023, TLV320AIC3104, AM3517

Hello.

I have a question about powering VDDS_DPLL_PER_CORE, VDDS_DPLL_MPU_USBHOST and VDDA1P8V_USBPHY, VDDA_DAC using LDO1 in TPS65023B powering on when 1.2V VDD_CORE comes up.

Can I group and power up together VDDS_DPLL_PER_CORE, VDDS_DPLL_MPU_USBHOST and VDDA1P8V_USBPHY, VDDA_DAC  or

I must to power up VDDS_DPLL_PER_CORE, VDDS_DPLL_MPU_USBHOST and  then VDDA1P8V_USBPHY, VDDA_DAC ?

Also, I want to connect VDDA_3P3V_USBPHY to LDO2 and power up at the same time as VDDS_DPLL_PER_CORE, VDDS_DPLL_MPU_USBHOST and  VDDA1P8V_USBPHY, VDDA_DAC.

Thank you.

  • 0
    TI__Genius 16690 points

      You could ramp up VDDS_DPLL_PER_CORE, VDDS_DPLL_MPU_USBHOST, VDDA1P8V_USBPHY and VDDA_DAC together after VDD_CORE becomes stable. This is described in the section "3.5.1 Power-up Sequence" of AM35x datasheet (SPRS550B–OCTOBER 2009–REVISED JULY 2010). You could also ramp up VDDA_3P3V_USBPHY at the same time above 1.8 V power supply group ramps up after VDD_CORE becomes stable.

  • 0 in reply to kshin
    Prodigy 30 points

    Hello!

    I have a question about powering the off chip peripherals (DDR2 memory, NAND flash, etc.) with TPS65023.

    When do I have to apply power to the peripherals, i.e. can I power the SD-card and NAND memories, the audio CODEC (TLV320AIC3104) and LAN PHY (KSZ8041TL) from the DCDC3 converter of the TPS65023 power supply? I also use DCDC3 to power VDDSHV at 3.3V.

    Can I also power the DDR2 memory chips from the DCDC2 converter (I use it to power VDDS, VDDS_SRAM_MPU, VDDS_SRAM_CORE_BG and VDDSOSC at 1.8V)?

    I couldn't find anything about the off-chip periperals power-up sequence in the AM3517 documentation. Please, help!

    Thanks in advance

  • 0 in reply to Müller
    TI__Genius 16690 points

    Hello,

    The AM35x data manual only defines the power up sequence for AM35x. AM35x SOM schematics from LogicPD would be a good reference if you have access to it.

  • 0 in reply to kshin
    Prodigy 30 points

    Thaks for your reply, Kazunobu Shin!

    I saw a kind of similar design where the DDR2 memory was powered from the same 1.8V source as the processor, so Ithink it'll do. I also plan to connect to the 3.3V peripherals to VDDHV. Anyway the their resets will be driven high only after the processor is also powered(using the INT output from TPS65023) or even later(if reset from the processor).

    Regards,

    Alex