Example Power Supply Utilizing Minimal Regulators; External Power Supply Descriptions - Intel PXA27 Series Design Manual

Mixed Voltage Design Considerations
Table 4-1. External Power Supply Descriptions
Name
VCC_BATT
VCC_IO
VCC_LCD
VCC_USB
VCC_MEM
VCC_BB
VCC_USIM
VCC_PLL
VCC_SRAM PWR_EN
VCC_CORE PWR_EN
NOTES:
1. VCC_USIM must be held to the VCC_IO specification when using alternate function other than USIM signals.
2. Any legal voltage between 0.85 V and 1.55 V is valid. There is no default.
4.3

Example Power Supply Utilizing Minimal Regulators

See Figure 4-1
minimum number of voltage supplies.
The 1.8 V regulators are shown in dashed lines to indicate where the regulators are used. Use either
the dashed black lines or the dashed lines if that peripheral is used in the system. However, ensure
both voltages (if used) are not connected together.
I:4-2
Enable Units
None Sleep-active units, oscillators
SYS_EN Peripheral I/O
SYS_EN LCD I/O
SYS_EN USB I/O
SYS_EN Memory Controller Interface
SYS_EN Baseband Interface
1
SYS_EN USIM Interface
PWR_EN Phase Locked Loops
Internal SRAM units
All other internal units
for an example of a power supply system for the PXA27x processor that uses the
Default
Allowed Levels
Voltage
(V)
3.0
3.3
3.3 1.8, 2.5, 3.0, 3.3
3.3
3.3 1.8, 2.5, 3.0, 3.3
3.3 1.8, 2.5, 3.0, 3.3
3.3 1.8, 3.0, 3.3
1.3
1.1
2
any variable 0.85-1.55
®
Intel PXA27x Processor Family Design Guide
Tolerance
(V) (%)
±
3.0 25
±
3.0, 3.3 10
±
10
±
3.0, 3.3 10
±
10
±
10
±
10
±
1.3 10
±
1.1 10
±
10