AM1707_1008 Datasheet, PDF (42/199 Pages) Texas Instruments – ARM Microprocessor

AM1707
SPRS637A – FEBRUARY 2010 – REVISED APRIL 2010
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6.3 Power Supplies
6.3.1 Power-on Sequence
The device should be powered-on in the following order:
• 1) RTC (RTC_CVDD) may be powered from an external device (such as a battery) prior to all other
supplies being applied or powered-up at the same time as CVDD. If the RTC is not used, RTC_CVDD
should be connected to CVDD. RTC_CVDD should not be left unpowered while CVDD is powered.
• 2a) CVDD core logic supply
• 2b) Other 1.2V logic supplies (RVDD, PLL0_VDDA). Groups 2a) and 2b) may be powered up together
or 2a) first followed by 2b).
• 3) All 1.8V IO supplies (USB0_VDDA18, USB1_VDDA18).
• 4) All digital IO and analog 3.3V PHY supplies (DVDD, USB0_VDDA33, USB1_VDDA33).
USB0_VDDA33 and USB1_VDDA33 are not required if both USB0 and USB1 are not used) and may
be left unconnected.USB0_VDDA33 is not required if USB0 is not used and may be left unconnected.
There is no specific required voltage ramp rate for any of the supplies.
RESET must be maintained active until all power supplies have reached their nominal values.
Note: Future devices may support higher performance at a higher core logic voltage (CVDD). If future
migration is desired, the current design should provide separate supplies for 2a) and 2b). If not, then 2a)
and 2b) may be provided by a single supply.
6.3.2 Power-off Sequence
The power supplies can be powered-off in any order as long as the 3.3V supplies do not remain powered
with the other supplies unpowered.
6.4 Unused USB0 (USB2.0) and USB1 (USB1.1) Pin Configurations
If one or both USB modules on the device are not used, then some of the power supplies to those
modules may not be required. This can eliminate the requirement for a 1.8V power supply to the USB
modules. The required pin configurations for unused USB modules are shown below.
Table 6-1. Unused USB0 and USB1 Pin Configurations
SIGNAL NAME
USB0_DM
USB0_DP
USB0_VDDA33
USB0_VDDA18
USB0_ID
USB0_VBUS
USB0_DRVVBUS/GP4[15]
USB0_VDDA12
USB1_DM
USB1_DP
USB1_VDDA33
USB1_VDDA18
AHCLKX0/AHCLKX2/USB_REFCLKIN/
GP2[11]
Configuration
(When USB0 and USB1 are not used)
No connect
No connect
No connect
No connect
No connect
No connect
No connect or use as alternate function
No connect
No connect
No connect
No connect
No connect
No connect or use as alternate function
Configuration
(When USB0 is used
and USB1 is not used)
Use as USB0 function
Use as USB0 function
3.3V
1.8V
Use as USB0 function
Use as USB0 function
Use as USB0 or alternate function
Internal USB0 PHY output connected to an
external filter capacitor
Ground
Ground
No connect
No connect
Use as USB0 or alternate function
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Peripheral Information and Electrical Specifications
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