Intel PXA27X Intel PXA27x Processor Power Supply Domains, External Power Supply Descriptions

Intel® PXA27x Processor Family Power Requirements

The terms run mode and normal mode are used interchangeably, although normal mode comprises both the run-mode and turbo-mode settings.

2.0Intel® PXA27x Processor Power Supply Domains

Viewed externally, the main or backup battery powers ten power-supply domains. Additional supply domains are present internally, but power for these is derived from the external supply inputs.

All functional units within a power domain connect to the same power supply and are powered up and down together. The PXA27x processor architecture, with its multiple power-supply domains, provides flexibility in system configuration (including selection of I/O voltages for different memory and peripherals) and efficient power management (for instance, flexibility in selecting which peripherals are powered at the same time). Together, these let system designers make power/ complexity trade-offs and optimize a product for intended markets.

Product designers can also choose to strap certain supplies together (to power several domains from a common regulator) to reduce complexity, cost, and the number of regulators in the system. Guidelines showing which supplies can be combined are provided in this document.

A summary of the voltage and tolerance requirements for each external supply input is shown in Table 1. Figure 1 shows the PXA27x processor internal and external power domains and their connections.

Table 1. External Power Supply Descriptions

Power Domain	Enable1	Units	Specified Levels	Tolerance
			(Volts)	(%)
VCC_BATT	None	Sleep-control subsystem, oscillators and	3.0	± 25
		real-time clock
VCC_IO	SYS_EN	Peripheral input/output	3.0, 3.3	±10 (@ 3.0 V
				=10%, -10.3%)
VCC_LCD	SYS_EN	LCD input/output	1.8, 2.5, 3.0, 3.3	+20,-5 (@ 1.8 V)
				otherwise ±10
VCC_MEM	SYS_EN	Memory controller input/output	1.8, 2.5, 3.0, 3.3	+20,-5 (@ 1.8 V)
				otherwise ±10
VCC_BB	SYS_EN	Baseband interface	1.8, 2.5, 3.0, 3.3	+20,-5 (@ 1.8 V)
				otherwise ±10
VCC_USIM	SYS_EN	USIM interface	1.8, 3.0	+20,-5 (@ 1.8 V)
				otherwise ±10
VCC_USB	SYS_EN	Differential USB input/output	3.0, 3.3	±10
VCC_PLL	PWR_EN	Phase-locked loops	1.3	±10
VCC_SRAM	PWR_EN	Internal SRAM units	1.1	±10
VCC_CORE	PWR_EN	CPU and other internal units	variable 0.85 – 1.551	-5 +10

NOTE: SYS_EN and PWR_EN are PXA27x processor output control signals.

1.PXA27x processors have different maximum frequencies and VCC_CORE voltages. Refer to both of the Intel® PXA27x Processor Family EMTSs for details.

6 Application Note