Analog Integrated Circuit Device Data
Freescale Semiconductor
51
13892
FUNCTIONAL DEVICE OPERATION
Because of an order from the United States International Trade Commission, BGA-packaged product lines and part numbers indicated here currently are not
available from Freescale for import or sale in the United States prior to September 2010: MC13892VK and MC13892VL in 139, 186 MAPBGA packages.
SUPPLIES
A system power scheme for portable devices is provided
which includes both switching and linear regulators. Various
operational modes are available for the power circuitry, which
may be accessible through SPI programming and the state of
the STANDBY pins. Programmable Standby mode
configuration allows automated system level control to
optimize quiescent efficiency without the need for or latency
of SPI intervention.
The switch mode supply subsystem include a core block
for clock generation, 4 step down (buck) switching regulators
and two step up (boost) switching regulators.
Linear regulators are provided for key power domains not
supplied directly by switching regulators or the battery. Pass
devices are integrated for most regulators for board area and
cost advantages. External PNP pass devices are used
selectively to help manage internal power dissipation.
A general application of the power tree is illustrated in the
Figure 6 diagram. Supply names are suggestive of typical
applications, but not restrictive.
Figure 6. General Application of the Power Tree
The minimum operating voltage for the supply tree while
maintaining the performance as specified is 3.0 V. For lower
voltages, the performance may be degraded.
BUCK CONVERTERS
Four buck switchers are provided with integrated power
switches and synchronous rectification. In a typical
application, SW1 and SW2 are used for supplying the
Application Processor core power domains. Split power
domains allow independent DVS control for processor power
optimization, or to support technologies with a mix of device
types with different voltage ratings. SW3 is used for powering
internal processor memory as well as low voltage peripheral
devices and interfaces, which can run at the same voltage
level. SW4 is used for powering external memory as well as
low voltage peripheral devices and interfaces, which can run
at the same voltage level.
An anticipated platform use case applies SW1 and SW2 to
processor power domains that require voltage alignment to
allow direct interfacing without bandwidth limiting
synchronizers.
The buck switchers are supplied from the system supply
BP, which is drawn from the main battery or the battery
charger (when present).
Figure 7 shows a high level block
diagram of the buck switchers.