AM4376: Power-up Sequencing

Robert Noe

Part Number: AM4376

By using simplified power sequence (Datasheet Figure 5-8 *) can I connect VDDS_DDR and VDD_MPU together? Because they have voltages near each other. 1.35V for DDR3L that can work with 1.325V (for VDD_MPU), so if I connect them there would be one less DC/DC. Power sequence would be as follow: 3.3V --> 1.8V --> 1.325V (VDDS_DDR, VDD_MPU) --> 1.1V (VDD_CORE, CAP_VDD_RTC)

I this a valid configuration?

* Simplified Power Sequencing With RTC Feature Disabled, Dual-Voltage IOs Configured as 3.3 V

Regards,

Robert

over 7 years ago

0 Ahmad_Rashed over 7 years ago

TI__Genius 13567 points

Hi Robert,
This has not been tested so I cannot say if this will work. Plus I would worry about noise from the MPU load steps affecting DDR stability.

Will this be achieved with discrete power ICs instead of one of our PMIC options? Let me ask our design / power expert on this.

0 Robert Noe over 7 years ago in reply to Ahmad_Rashed

Intellectual 440 points

Hi Ahmad

To answer your question, yes this will be a discrete power solution.
My problem is with correct power-up sequencing.
Did you ask experts about this?

Regards,
Robert

0 sivak over 7 years ago in reply to Robert Noe

TI__Genius 9655 points

Robert

We don't recommend shorting VDD_MPU with VDDS_DDR. There are noise concerns (as Ahmad noted above), violates the power sequence and if using extended temperature has impact on power on hours as shown in Table 5.3 in the AM437x data sheet.

Regards, Siva

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AM4376: Power-up Sequencing