AM62A7-Q1: MCU_PORz slew rate

Hello one and zero

Thank you for the query.

The MCU_PORz is the main cold reset input and the internal reset circuit is controlled by the MCU_PORz input signal.

In case where there is a slow ramp, the internal circuit (has hysteresis enabled) is likely to see multiple reset transitions that could cause the internal reset to not complete and could result in an unexpected behavior.

.We do not recommend a slow slew input. The recommendation is to use a discrete push pull output buffer which has a slew 0f ~10 ns

A glitch filter of 22pF is recommended as a provision.

Other than the RESSET input, you can follow the slew rate requirements in the data sheet for the other IOS.

Regards,

Sreenivasa

Is it only for AM62A74 chip? Does this recommendation hold for AM6204?

Is it planned to release an errata or datasheet update with the proposed 10 ns recommendation?

Hi Bibin,

The recommendation is based on the use case where an slow slew open drain output is connected to the cold reset input MCU_PORz input and for processor EMC performance robustness.

In the use case that was mentioned in the E2E above the use case is connecting the nRSTOUT of PMIC (open drain output)

The PMIC nRSTOUT is a open drain slow ramp output from the PMIC.

When a slow ramp reset input is applies to the MCU_PORz there are likely chances that the internal reset circuit could glitch.

A discrete push pull output buffer is recommended to minimze the slew.

We do not have a spec for the MCU_PORz. The recommendation is faster the better. (<10ns)

When you use a push pull output you are likely to achieve the rise time.

We do not see the need to update the data sheet or errata for use case specific recommendations. 

We have the guidelines captured in the schematic design user's guide.

Regards,

Sreenivasa

Hi Bibin,

Please refer below documents including the schematic design checklist.

Recommended References for review and design of custom board
AM62D-Q1
AM62Dx Sitar Processors datasheet
www.ti.com/.../sprspb5

AM62D
Sitara Processors Technical Reference Manual sprujd4
www.ti.com/.../sprujd4

AM62Ax
Data sheet
AM62Ax Sitara Processors Data Sheet 
www.ti.com/.../sprsp77

AM62Ax
Sitara Processors Technical Reference Manual spruj16b
www.ti.com/.../spruj16

Hardware Design Considerations
www.ti.com/.../sprad85
DDR Board Design and Layout Guidelines
www.ti.com/.../sprad66
Schematic Design and Review Checklist for AM62Ax processor family
www.ti.com/.../sprado2
Schematic Design and Review Checklist combined for sitara processor families
www.ti.com/.../sprad21
Errata AM62A
www.ti.com/.../sprz544

AM62A Schematic checklist
e2e.ti.com/.../faq-am625-am623-am62a-am62p-am62d-q1-am64x-am243x-design-recommendations-custom-board-hardware-design---schematics-review-checklists

AM62A Schematic self-review
e2e.ti.com/.../faq-am62a3-am62a7-am62a7-q1-am62a3-am62a3-q1-am62d-q1-design-recommendations-custom-board-hardware-design---custom-board-schematics-self-review
e2e.ti.com/.../faq-am625-am623-am62a-design-recommendations-commonly-observed-errors-during-custom-board-hardware-design-sk-schematics-updates-for-design-update-note
e2e.ti.com/.../faq-am625-am625-am623-am62a-am62p-am62d-q1-am64x-am243x-design-recommendations-custom-board-hardware-design---list-of-errors-observed-during-customer-schematics-review
e2e.ti.com/.../faq-am625-am623-am62a-am62p-am62d-q1-am64x-am243x-design-recommendations-custom-board-hardware-design---queries-related-to-soc-data-sheet-pin-attributes

Frequently Asked Questions FAQs for schematics D-Note, R-Note
e2e.ti.com/.../faq-am62a7-am62a7-q1-am62a3-am62a3-q1-am62a1-q1-am62d-q1---custom-board-hardware-design---design-and-review-notes-for-reuse-of-sk-am62a-lp-schematics

Frequently Asked Questions FAQs
e2e.ti.com/.../faq-custom-board-hardware-design---master-complete-list-of-faqs-for-all-sitara-processor-am62x-am64x-am243x-am335x-families
e2e.ti.com/.../faq-am62a7-am62a7-q1-am62a3-am62a3-q1-custom-board-hardware-design---faqs-related-to-processor-collaterals-functioning-peripherals-interface-and-starter-kit
e2e.ti.com/.../faq-am62x-am64x-custom-board-hardware-design-how-to-handle-used-unused-pins-peripherals-e-g-gpios-serdes-usb-csi-mmc-emmc-sd-card-csi-oldi-dsi

Downloadable design files on TI.com list for SK
SK-AM62A-LP Design Package Folder and Files List
www.ti.com/.../sprt781
www.ti.com/.../sprr491

AUDIO-AM62D-EVM
AM62D expandable hardware for premium audio
www.ti.com/.../sprcal5

Regards,

Sreenivasa