SPRABJ8B September   2022  – November 2023 AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1 , AM263P4

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
    1. 1.1 Acronyms
  5. 2 Power
    1. 2.1 Discrete DC-DC Power Solution
    2. 2.2 Integrated PMIC Power Solution
    3. 2.3 Power Decoupling and Filtering
    4. 2.4 Power Consumption
    5. 2.5 Power Distribution Network
      1. 2.5.1 Simulations
        1. 2.5.1.1 Core Digital Power 1.2 V
        2. 2.5.1.2 Digital/Analog I/O Power 3.3 V
    6. 2.6 e-Fuse Power
  6. 3 Clocking
    1. 3.1 Crystal and Oscillator Input Options
    2. 3.2 Output Clock Generation
    3. 3.3 Crystal Selection and Shunt Capacitance
    4. 3.4 Crystal Placement and Routing
  7. 4 Resets
  8. 5 Bootstrapping
    1. 5.1 SOP Signal Implementation
    2. 5.2 OSPI/QSPI Memory Implementation
    3. 5.3 ROM OSPI/QSPI Boot Requirements
  9. 6 JTAG Emulators and Trace
  10. 7 Multiplexed Peripherals
  11. 8 Digital Peripherals
    1. 8.1 General Digital Peripheral Routing Guidelines
  12. 9 Analog Peripherals
    1. 9.1 General Analog Peripheral Routing Guidelines
      1. 9.1.1 Resolver ADC Routing Guidelines
  13. 10Layer Stackup
    1. 10.1 Key Stackup Features
  14. 11Vias
  15. 12BGA Power Fan-Out and Decoupling Placement
    1. 12.1 Ground Return
    2. 12.2 1.2 V Core Digital Power
      1. 12.2.1 Key Layout Considerations
    3. 12.3 3.3 V Digital and Analog Power
      1. 12.3.1 Key Layout Considerations
    4. 12.4 1.8 V Digital and Analog Power
      1. 12.4.1 Key Layout Considerations
  16. 13References
  17.   Revision History

2.6 e-Fuse Power

The AM263x and AM263Px one-time programmable, e-Fuse memory can be utilized for storing customer cryptographic keys and other information specific to individual devices. These e-Fuse memory locations can only be programmed when the target device VPP, e-Fuse power pin, is powered by a 1.7 V nominal output voltage, 100 mA peak current supply. This 1.7V VPP power supply can be onboard or off-board. The specific placement of the VPP supply and implementation depend on how the e-Fuse memory will be utilized by the designer. The implementation should follow the diagram shown in Figure 2-18

GUID-20230518-SS0I-TV3M-B8NF-CFQMWMVGVH4M-low.svg Figure 2-18 AM263x and AM263Px e-Fuse VPP Power Implementation Example

The AM263Px has the option to source VPP internally using the ANALDO. The ANALDO must be overwritten to provide 1.7V during e-Fuse programming, then reverted back to normal operation.

The e-Fuse programming typically follows one or both of the following scenarios:

  • Factory programming – e-Fuse memory programmed during post assembly test of the AM263x system.
  • Field programming – e-Fuse memory is programmed after the device has left the factory and is installed in the end-equipment.

If the factory programming scenario is all that is required for a product, then it is typically preferable for the VPP power supply to be implemented off-board since this reduces the number of supplies required to be placed on the PCB assembly. The VPP supply would only be used during this programming sequence, so keeping it on the board would not be an efficient use of PCB floor plan area, BOM cost or test time.

However, if the e-Fuse memory must be programmed outside the factory environment, the VPP power must either be supplied from an onboard component or from an attached accessory board that can supply this power as needed.

In the case of the TMDSCNCD263 controlCard evaluation module design, the VPP supply was left on the board to enable convenient e-fuse programming by customers experimenting with this process. On the controlCard the TLV75801PDRVR LDO, U66, was used to drop down the 3.3 V system I/O voltage to the VPP 1.7 V. Additionally, the GPIO expander, U50 was used to toggle the VPP_LDO_EN pin to enable/disable the LDO in the required sequence for e-Fuse programming.

For the full VPP electrical requirements and e-Fuse programming sequence, see the VPP Specifications for One-Time Programmable (OTP) eFuses section in the AM263x Sitara™ Microcontroller Data Sheet or AM263Px Sitara™ Microcontroller Data Sheet.