BCM4330 Preliminary Data Sheet
Low-Power Shutdown
Low-Power Shutdown
The BCM4330 provides a low-power shutdown feature that allows the device to be turned off while the host,
and any other devices in the system, remain operational. When the BCM4330 is not needed in the system,
VDDRF and VDDC are shut down while VDDO remains powered. This allows the BCM4330 to be effectively off
while keeping the I/O pins powered so that they do not draw extra current from any other devices connected
to the I/O.
During a low-power shut-down state, provided VDDO remains applied to the BCM4330, all outputs are
tristated, and most inputs signals are disabled. Input voltages must remain within the limits defined for normal
operation. This is done to prevent current paths or create loading on any digital signals in the system, and
enables the BCM4330 to be fully integrated in an embedded device and take full advantage of the lowest
power-savings modes.
Two signals on the BCM4330, the frequency reference input (WRF_XTAL_ON) and the LPO input, are designed
to be high-impedance inputs that do not load down the driving signal even if the chip does not have VDDO
power applied to it.
When the BCM4330 is powered on from this state, it is the same as a normal power-up and the device does
not contain any information about its state from before it was powered down.
®
BROADCOM
BCM4330 Preliminary Data Sheet
April 28, 2011 • 4330-DS304-RI
Page 30
CYPRESS [ CYPRESS ]
