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AM2434: 1.8V power supply connections

Daisuke Maeda
Guru 20325 points
Part Number: AM2434
Other Parts Discussed in Thread: AM6412, AM6422, AM6442, , SK-AM64B

The 1.8V power inputs listed below are recommended to be connected to the analog power supply rails in the Schematic Design Guidelines and Schematic Review Checklist.

VDDS_MMC0
VDDA_MCU
VDDS_OSC
VDDA_PLL0
VDDA_PLL1
VDDA_PLL2
VDDA_ADC0
VDDA_1P8_SERDES0
VDDA_1P8_USB0
VDDA_TEMP0
VDDA_TEMP1
VMON_1P8_SOC
VMON_1P8_MCU

AM6442 , AM6422 , AM6412 and AM2434 Processor Schematic Design Guidelines and Schematic Review Checklist (Rev. E)
www.ti.com/.../spracu5e.pdf
6.1.1.1.4 Peripheral Analog Power Supply Checklist (page 36)

The 1.8V power inputs listed below are connected to the analog power supply rail in SK-AM64B.

VDDA_MCU
VDDS_OSC
VDDA_PLL0
VDDA_PLL1
VDDA_PLL2
VDDA_1P8_SERDES0
VDDA_1P8_USB0
VDDA_TEMP0
VDDA_TEMP1

The 1.8V power inputs listed below are connected to the digital power supply rail in SK-AM64B.

VDDSHV4
VDDS_MMC0
VMON_1P8_SOC
VMON_1P8_MCU

It appears in the following thread that connecting VDDS_MMC0 to the analog power supply rails is not recommended.

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1465634/am6421-isolation-of-vdds_mmc0-and-1-8v-analogue-systems-by-type-of-filter

Is it recommended that VDDS_MMC0 be connected to the analog power supply rails?

If VMON_1P8_SOC or VMON_1P8_MCU is used, can it be connected to any 1.8V power supply rails?

If VMON_1P8_SOC or VMON_1P8_MCU is not used, is it recommended to connect it to the analog power supply rails?

Best regards,

Daisuke

 

  • +1
    TI__Guru**** 206590 points

    Hello Daisuke

    Thank you for the query.

    Daisuke Maeda said:
    Is it recommended that VDDS_MMC0 be connected to the analog power supply rails?

    The recommendation is to follow the EVM or SK. 

    I will review the checklist. 

    Daisuke Maeda said:
    e2e.ti.com/.../quote]

    The E2E discuss on implementing ferrite filter

    Daisuke Maeda said:
    If VMON_1P8_SOC or VMON_1P8_MCU is used, can it be connected to any 1.8V power supply rails?

    The recommendation is to connect to the 1.8V supply of interest that requires monitoring.

    Daisuke Maeda said:
    If VMON_1P8_SOC or VMON_1P8_MCU is not used, is it recommended to connect it to the analog power supply rails?

    The recommendation is to connect to the supply of interest (including Analog 1.8V) for future use.

    Reger pin connectivity requirements for connecting VMON when not used.

    Regards,

    Sreenivasa

    [/quote]
  • 0 in reply to Kallikuppa Sreenivasa
    Guru 20325 points

    Sreenivasa-san,

    Thank you for your reply.

    Why is it recommended to connect VDDS_MMC0, VMON_1P8_SOC, and VMON_1P8_MCU to the analog power supply rails in the Schematic Design Guidelines and Schematic Review Checklist? Are these typos?

    " Supply connection for peripheral analog power supply rails (VDDS_MMC0, VDDA_MCU, VDDS_OSC, VDDA_PLL0, VDDA_PLL1, VDDA_PLL2, VDDA_ADC0, VDDA_1P8_SERDES0, VDDA_1P8_USB, VDDA_TEMP0, VDDA_TEMP1, VMON_1P8_SOC, VMON_1P8_MCU) "

    " Recommended supply voltage 1.8V is connected to the peripheral analog power supply rails VDDS_MMC0, VDDA_MCU, VDDS_OSC, VDDA_PLL0, VDDA_PLL1, VDDA_PLL2, VDDA_ADC0, VDDA_1P8_SERDES0, VDDA_1P8_USB, VDDA_TEMP0, VDDA_TEMP1, VMON_1P8_SOC, VMON_1P8_MCU "

    Best regards,

    Daisuke

  • +1 in reply to Daisuke Maeda
    TI__Guru**** 206590 points

    Hello Daisuke

    Thank you.

    Daisuke Maeda said:
    Why is it recommended to connect VDDS_MMC0, VMON_1P8_SOC, and VMON_1P8_MCU to the analog power supply rails in the Schematic Design Guidelines and Schematic Review Checklist? Are these typos?

    I do not see any concern with VMON_1P8_SOC, VMON_1P8_MCU connected to analog supply, this depends on the customer use case.

    VDDS_MMC0 connection recommendations will be reviewed, and the required updates will be considered in the next revision of the guidelines.

    Regards,

    Sreenivasa

  • 0 in reply to Kallikuppa Sreenivasa
    Guru 20325 points

    Sreenivasa-san,

    Thank you for your reply.

    I have an additional question.

    How should each of VDDS_OSC and VDDA_MCU be connected to power supply rails?

    VDDS_OSC and VDDA_MCU supplies are recommended to be always connected in the Schematic Design Guidelines and Schematic Review Checklist.

    AM6442 , AM6422 , AM6412 and AM2434 Processor Schematic Design Guidelines and Schematic Review Checklist (Rev. E)
    www.ti.com/.../spracu5e.pdf
    6.1.1.1 Core and Peripherals Supplies (page 32)
    "The recommendation is to always connect VDDS_OSC and VDDA_MCU supplies"

    On EVM, VDDS_OSC is connected directly to 1.8V analog power supply rail, and VDDA_MCU is connected via a ferrite filter.

    On SK, since ADC is unused, VDDA_MCU is connected to GND.

    Can each of VDDS_OSC and VDDA_MCU be connected via a ferrite filter?

    Best regards,

    Daisuke

  • +1 in reply to Daisuke Maeda
    TI__Guru**** 206590 points

    Hello Daisuke

    Thank you.

    Daisuke Maeda said:
    On SK, since ADC is unused, VDDA_MCU is connected to GND.

    Can you please confirm if you regarding VDDA_ADC or VDDA_MCU

    Daisuke Maeda said:
    Can each of VDDS_OSC and VDDA_MCU be connected via a ferrite filter?

    Should be Ok although the ferrite for VDDS_OSC seems to be optional.

    In the SK the VDDA_OSC connects to VDDA_1V8 (PMIC LDO output).

    Regards,

    Sreenivasa

  • 0 in reply to Kallikuppa Sreenivasa
    Guru 20325 points

    Sreenivasa-san,

    Thank you for your reply.

    Kallikuppa Sreenivasa said:
    Can you please confirm if you regarding VDDA_ADC or VDDA_MCU

    On SK, VDDS_OSC is connected directly to 1.8V analog power supply rail, and VDDA_MCU is connected to GND since ADC is unused.

    Kallikuppa Sreenivasa said:
    Should be Ok although the ferrite for VDDS_OSC seems to be optional.

    Each of VDDS_OSC and VDDA_MCU will be connected to 1.8V analog power supply rail via a ferrite filter.

    Then, what do the following recommendation in the Schematic Design Guidelines and Schematic Review Checklist mean?

    "The recommendation is to always connect VDDS_OSC and VDDA_MCU supplies"

    AM6442 , AM6422 , AM6412 and AM2434 Processor Schematic Design Guidelines and Schematic Review Checklist (Rev. E)
    www.ti.com/.../spracu5e.pdf
    6.1.1.1 Core and Peripherals Supplies (page 32)

    Best regards,

    Daisuke

  • 0 in reply to Daisuke Maeda
    TI__Guru**** 206590 points

    Hello Daisuke

    I see VDDA_MCU connected to VDDA_1V8_MCU

    Connecting VDDA_MCU to ground is not a valid use case.

    Daisuke Maeda said:
    Can you please confirm if you regarding VDDA_ADC or VDDA_MCU

    On SK, VDDS_OSC is connected directly to 1.8V analog power supply rail, and VDDA_MCU is connected to GND since ADC is unused.

    Please share the picture where VDDA_MCU is connected to ground.

    Regards,

    Sreenivasa

  • 0 in reply to Kallikuppa Sreenivasa
    Guru 20325 points

    Sreenivasa-san,

    Thank you for your reply.

    I’m sorry. For some reason I confused VDDA_MCU with VDDA_ADC.

    On EVM and SK, VDDS_OSC is connected directly to 1.8V analog power supply rail, and VDDA_MCU is connected via a ferrite filter.

    What do the following recommendation in the Schematic Design Guidelines and Schematic Review Checklist mean?

    "The recommendation is to always connect VDDS_OSC and VDDA_MCU supplies"

    Does this mean connecting VDDS_OSC and VDDA_MCU to the same power supply?

    Best regards,

    Daisuke
  • +1 in reply to Daisuke Maeda
    TI__Guru**** 206590 points

    Hello Daisuke

    Thank you.

    Daisuke Maeda said:
    I’m sorry. For some reason I confused VDDA_MCU with VDDA_ADC.

    No worries.

    Daisuke Maeda said:
    "The recommendation is to always connect VDDS_OSC and VDDA_MCU supplies"

    The note is reminding that these 2 supplies should be connected irrespective of the clock configuration or internal architecture where MCU is not used.

    Regards,

    Sreenivasa