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Bluetooth Power Management Unit

BCM4354 Data Sheet

BROADCOM CONFIDENTIAL

Broadcom®

October 15, 2014 • 4354-DS109-R

Page 39

BBC Power Management

The following are low-power operations for the BBC:

• Physical layer packet-handling turns the RF on and off dynamically within transmit/receive packets.

• Bluetooth-specified low-power connection modes: sniff, hold, and park. While in these modes, the

BCM4354 runs on the low-power oscillator and wakes up after a predefined time period.

• A low-power shutdown feature allows the device to be turned off while the host and any other devices in the

system remain operational. When the BCM4354 is not needed in the system, the RF and core supplies are

shut down while the I/O remains powered. This allows the BCM4354 to effectively be off while keeping the

I/O pins powered so they do not draw extra current from any other devices connected to the I/O.

During the low-power shut-down state, provided VDDIO remains applied to the BCM4354, all outputs are

tristated, and most input 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 BCM4354 to be fully integrated in an embedded device to take full advantage of the lowest

power-saving modes.

Two BCM4354 input signals are designed to be high-impedance inputs that do not load the driving signal

even if the chip does not have VDDIO power supplied to it: the frequency reference input (WRF_TCXO_IN)

and the 32.768 kHz input (LPO). When the BCM4354 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 the time before it was

powered down.

FM Power Management

The BCM4354 FM subsystem can operate independently of, or in tandem with, the Bluetooth RF and BBC

subsystems. The FM subsystem power management scheme operates in conjunction with the Bluetooth RF and

BBC subsystems. The FM block does not have a low power state, it is either on or off.

Wideband Speech

The BCM4354 provides support for wideband speech (WBS) using on-chip SmartAudio technology. The

BCM4354 can perform subband-codec (SBC), as well as mSBC, encoding and decoding of linear 16 bits at

16 kHz (256 Kbps rate) transferred over the PCM bus.

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