SPRABJ8D September   2022  – May 2025 AM2612 , AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1 , AM263P2 , AM263P2-Q1 , AM263P4 , AM263P4-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  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
      1. 2.3.1 ADC/DAC Voltage Reference Decoupling
    4. 2.4 Estimated Power Consumption
    5. 2.5 Power Distribution Network
      1. 2.5.1 Simulations
        1. 2.5.1.1 Core Digital Power 1.2V
        2. 2.5.1.2 Digital and Analog I/O Power 3.3V
    6. 2.6 eFuse 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
  9. 6 OSPI and QSPI Memory Implementation
    1. 6.1 ROM OSPI and QSPI Boot Requirements
      1. 6.1.1 AM263x QSPI Boot Pin Requirements
      2. 6.1.2 AM263Px OSPI and QSPI Boot Pin Requirements
      3. 6.1.3 AM261x OSPI and QSPI Boot Pin Requirements
    2. 6.2 Additional OSPI and QSPI References
  10. 7 Debug Interfaces
    1. 7.1 JTAG Emulators and Trace
    2. 7.2 UART
  11. 8 USB
    1. 8.1 USB Device Mode
    2. 8.2 USB Host Mode
  12. 9 Multiplexed Peripherals
  13. 10Digital Peripherals
    1. 10.1 General Digital Peripheral Routing Guidelines
    2. 10.2 Trace Length Matching
  14. 11Analog Peripherals
    1. 11.1 General Analog Peripheral Routing Guidelines
      1. 11.1.1 Resolver ADC Routing Guidelines
  15. 12Layer Stackup
    1. 12.1 Key Stackup Features
  16. 13Vias
  17. 14BGA Power Fan-Out and Decoupling Placement
    1. 14.1 Ground Return
      1. 14.1.1 Ground Return - ZCZ Package AM26x Devices
      2. 14.1.2 Ground Return - ZNC and ZFG Package AM261x Devices
    2. 14.2 1.2V Core Digital Power
      1. 14.2.1 1.2V Core Digital Power Key Layout Considerations - ZCZ
      2. 14.2.2 1.2V Core Digital Power Key Layout Considerations - ZFG
    3. 14.3 3.3V Digital and Analog Power
      1. 14.3.1 3.3V I/O Power Key Layout Considerations - ZCZ
      2. 14.3.2 3.3V I/O Power Key Layout Considerations - ZFG
    4. 14.4 1.8V Digital and Analog Power
      1. 14.4.1 1.8V Key Layout Considerations - ZCZ
      2. 14.4.2 1.8V Key Layout Considerations - ZFG
  18. 15Summary
  19. 16References
  20. 17Revision History

2.2 Integrated PMIC Power Solution

A PMIC-based power tree allows for a more streamlined, single-chip design for controlling the power rails in an AM26x system. Several Texas Instruments PMICs are recommended for use with AM26x MCUs, and are detailed in the table below:

Table 2-3 AM26x PMICs
PMIC Orderable Part Number AM26x Target Device TI EVM / Reference Design Example
TPS6538600QDCARQ1 + TPS6290x-Q1(1)
  • TPS62903x-Q1 = 3A supply for AM263x/AM263Px
  • TPS62902x-Q1 = 2A supply for AM261x
 AM263x
AM263Px AM263Px controlCARD (TMDSCNCD263P)
AM261x AM261x controlSOM (AM261-SOM-EVM)
TPS65036x(2) AM261x AM261x LaunchPad (LP-AM261)
TPS65219x AM263Px
TPS65214x AM261x
(1) TPS6290x-Q1 is required to supply the 1.2V (AM263x, AM263Px, Automotive-grade AM261x) / 1.25V (Industrial-grade AM261x) core voltage to the AM26x device. The correct orderable part number to supply 3A for AM263x and AM263Px and 2A for AM261x is requried.
(2) There are multiple orderable part numbers of this PMIC associated with AM261x. See Table 2-6 for additional details.

Using TPS653860 with AM26x

The AM263Px controlCard EVM and AM261x controlSOM EVM designs make use of a multirail power supply for microcontrollers in safety-relevant applications (TPS6538600QDCARQ1). The PMIC integrates four supply rails to power the MCU, CAN, and other on-board peripherals.

Note: This implementation requires a separate TPS62902QRYTQ1 (3A for AM263x/AM263Px) / TPS62902QRYTQ1 (2A for AM261x) buck converter to supply the AM26x core voltage

The NRES output of the PMIC needs to be used to help drive the PORz reset input to the AM263x, AM263Px, or AM261x device to make sure the power on sequencing of the power rails is complete before releasing the MCU from reset.

AM263Px TMDSCNCD263P PMIC Implementation Figure 2-5 AM263Px TMDSCNCD263P PMIC Implementation
Table 2-4 TPS6538600QDCARQ1 Configuration for AM26x Devices
Output Power Rail Voltage Purpose Enabled at Power-On?
BB_OUT 6V Power input to separate 1.2V/1.25V regulator for AM26x VDD/VDDAR supply ✓
LDO1_OUT 3.3V AM26x IO voltage supply ✓
LDO2_OUT 3.3V System IO and peripheral hardware voltage supply ✓
LDO3_OUT 5V System supply and peripheral hardware voltage
LDO4_OUT 1.8V ADC voltage refrence supply
PLDO1_OUT CONFIGURABLE
PLDO2_OUT CONFIGURABLE
Note: SPI writes to the PMIC internal registers are required to enable power rails that do not come up by default at power-on.

Using TPS650360x with AM261x

The AM261x LaunchPad EVM design makes use of the smaller-package, lower-cost TPS65036x PMIC. This PMIC integrates four supply rails to power the MCU and other on-board peripherals.

Note: This PMIC can output 1.2V or 1.25V at 2A, which meets the VDD CORE supply requirements of the AM261x MCU. AM263x and AM263Px require 1.2V at 3A, so this PMIC must not be used to power these devices.
LP-AM261 PMIC Implementation Figure 2-6 LP-AM261 PMIC Implementation
Table 2-5 TPS65036x Configuration on LP-AM261
Output Power Rail Voltage Purpose Enabled at Power-On?
BUCK1 3.3V AM261x IO voltage and peripheral supply ✓
BUCK2 2.5V System Ethernet PHY supply ✓
BUCK3 1.25V (500MHz Industrial-grade AM261x) AM261x core voltage supply ✓
LDO 1.8V Flash IO voltage supply ✓

There are several variants of this PMIC depending on what supply voltages and features are required for an AM261x system.

Table 2-6 TPS65036x Variants for AM261x
Orderable Part Number BUCK1 BUCK2 BUCK3 LDO WD Enabled
TPS65036501RAYRQ1 3.3V 2.5V 1.25V (for Industrial-grade AM261x) 1.8V (for 1.8V IO external flash) YES
TPS65036601RAYRQ1 3.3V 2.5V 1.2V (for Automotive-grade AM261x) 1.8V (for 1.8V IO external flash) YES
PTPS65036605RAYRQ1 5V 3.3V 1.25V (for Industrial-grade AM261x) 1.8V or 3.3V YES
TPS65036608RAYRQ1 3.3V 1.8V 1.25V (for Industrial-grade AM261x) BYPASS YES
Note: Watchdog Enabled refers to the PMIC's watchdog Long Window Timer, a 12 minute timer that stops the PMIC, MCU operation from hanging if the system is idle for 12 minutes or longer. This feature is relevant for applications where safety is a priority. When the Watchdog is enabled, the PMIC asserts a reset if left idle for 12 minutes.

For the TPS650360x variants with the Watchdog enabled, this can be disabled via an I2C write to the PMIC registers, or by connecting the GPIO pin (pin 13) to the VDD_1P8 pin (pin 3) or any other supply that comes up before the PMIC ramps. If the watchdog is to be disabled using this hardware method, then the power supply pulling the GPIO pin high must ramp before the PMIC turns on. This way, the internal bit to disable the PMIC is set before the PMIC powers on.

The nRSTOUT output of the PMIC must be used to help drive the PORz reset input to the AM261x device to make sure the power on sequencing of the power rails is complete before releasing the MCU from reset. For more information, see Figure 4-3.