Personal Computer User Manual

Intel® PXA27x Processor Family Power Requirements
Application Note 5
1.0 Introduction
The Intel® PXA27x Processor Family (PXA27x processor) is a highly integrated system-on-chip
optimized for handheld battery-powered devices such as PDAs and 2.5G or 3G cell phones. The
PXA27x processor is ideal for products requiring substantial computing and multimedia capability
with very low power consumption.
The PXA27x processor combines a high-performance CPU with a variety of integrated peripheral
functions. The processor has separate power supply domains for the processor core, memory, and
peripherals to enable low-power system design. The PXA27x processor provides several dedicated
control signals as well as an I
2
C interface to connect to an external power management integrated
circuit.
Other system components, such as SDRAM and flash memory, audio codecs, touchscreen
controllers, and specialized companion chips, have with their own unique power requirements. In
many designs, a highly integrated power controller supplies power for these other components,
particularly those that interface directly to the PXA27x processor. An advanced power controller
can contain circuitry for charging batteries, powering the display panel, and include other analog
functions required by the system.
In any system design, factors such as operating conditions, application workload, environmental
considerations and the sophistication of the device’s power management software all play a role in
determining the amount of power consumed. When designing a system, manufacturers need to take
into account where the device is intended to be used (such as high temperature environments) and
what it is expected to do for an end user (such as play a game, a video or do simple email
transactions).
The Intel® PXA27x Processor Family EMTS provides manufacturers with a typical system power
consumption specification for all frequencies of the processor family. The purpose of this
application note is to provide guidance on how power consumption, in a typical environment can
change, based on different software workloads. In addition, this application note provides further
details on the requirements for providing power to the processor and for interfacing to its power
control signals, including behavioral requirements and typical system design examples under these
workloads.
The power numbers generated utilized Intel development platforms in lab conditions and the
information provided should be used as a guideline only.
1.1 Naming Conventions
In this document, active low items are prefixed with a lowercase “n”.
nRESET
Bits within a signal name are enclosed in angle brackets:
EXTERNAL_ADDRESS<31:0>
nCS<1>
Bits within a register bit field are enclosed in square brackets:
REGISTER_BITFIELD[3:0]
REGISTER_BIT[0]