BCM43907 Preliminary Data Sheet
Power-Off Shutdown
Power-Off Shutdown
The BCM43907 provides a low-power shutdown feature that allows the device to be turned off while the host,
and any other system devices remain operational. When the BCM43907 is not needed in the system,
VDDIO_RF and VDDC are shut down while VDDIO remains powered. This allows the BCM43907 to be
effectively off while keeping the I/O pins powered so that they do not draw extra current from devices connected
to the I/O.
During a low-power shutdown state, provided VDDIO remains applied to the BCM43907, 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
BCM43907 to be fully integrated in an embedded device while taking full advantage of the lowest power-saving
modes.
When the BCM43907 is powered on from this state, it is the same as a normal power-up and does not retain
any information about its state from before it was powered down.
Power-Up/Power-Down/Reset Circuits
The BCM43907 has two signals (see Table 2) that enable or disable circuits and the internal regulator blocks,
allowing the host to control power consumption. For timing diagrams of these signals and the required power-
up sequences, see Section 18: “Power-Up Sequence and Timing,” on page 122.
Table 2: Power-Up/Power-Down/Reset Control Signals
Signal
Description
REG_ON
This signal is used by the PMU to power up the BCM43907. It controls the internal
BCM43907 regulators. When this pin is high, the regulators are enabled and the device is
out of reset. When this pin is low, the device is in reset and the regulators are disabled. This
pin has an internal 200 k pull-down resistor that is enabled by default. It can be disabled
through programming.
HIB_REG_ON_IN This signal is used by the hibernation block to decide whether or not to power down the
internal BCM43907 regulators. If HIB_REG_ON_IN is low, the regulators will be disabled.
For a signal at HIB_REG_ON_IN to function as intended, HIB_REG_ON_OUT must be
connected to REG_ON.
Broadcom®
March 12, 2016 • 43907-DS104-R
Page 23
BROADCOM CONFIDENTIAL
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