Filter
Top Products
A-4 PXA250 and PXA210 Applications Processors Design Guide
SA-1110/Applications Processor Migration
A.1.3 Power Delivery
Although both products are tolerant to 3.3 V inputs and outputs, there is a difference in the supply
voltage that drives the transistors of the microprocessor megacell. The PXA250 applications
processor takes advantage of lower supply voltages to offer substantial power consumption
savings. A design using SA-1110 has a supply voltage of 1.55 V to 1.75 V. The PXA250
applications processor is rated to 1.4 V maximum.
Drive the PXA250 applications processor core voltage pins at a lower voltage than the SA-1110 to
reduce overall power consumption. The choice of voltage impacts the maximum upper frequency
of operation so check the PXA250 documentation for the correct voltages as they are application
dependent.
Also notice that the PXA250 applications processor supports independent power sources for Core,
IO, Memory Bus, phase lock loops (PLLs), and a backup battery. It is recommended that these be
independent power sources.
A.1.4 Package
The SA-1110 and the PXA250 applications processors are similar but not identical. The ball pitch
of 1 mm is the same and the body outlines are both 17x17 mm but the heights are different. The
PXA250 applications processor contains 4-layers within the package making it fractionally thicker
than the SA-1110 2-layer package.
When migrating to the PXA210
applications processor there a few limits to functionality:
• The upper 16-bits of the databus are unavailable
• Only two of the primary GPIO pins are available
• The upper two SDRAM bank strobes are unavailable
• UART hardware flow control and external DMA are not accessible
This smaller package than the SA-1110 accommodates a lower overall power envelope that may
restrict upper voltage operation and maximum frequency for power consumption reasons. The ball
pitch is reduced to 0.8 mm and the package is much thinner than the mBGA.
A.1.5 Clocks
The crystal inputs for the PXA250 applications processor are at the same frequency as those for the
SA-1110:
• High frequency input of 3.6864 MHz
• Slow real-time clock source of 32.768 KHz.
The input frequency requirements are relatively low, such that any crystal that is an AT-cut style
with a certain amount of shunt capacitance will work for both products.
The actual PLL design and process technology is different between the two products, such that a
marginal SA-1110 design may not work with the PXA250 applications processor. Please refer to
the product specifications of each device for further details.