BCM4354 datasheet(35/192 Pages) CYPRESS

35 / 192 page

Bluetooth Radio

BCM4354 Data Sheet

BROADCOM CONFIDENTIAL

Broadcom®

October 15, 2014 • 4354-DS109-R

Page 34

Receiver

The receiver path uses a low-IF scheme to downconvert the received signal for demodulation in the digital

demodulator and bit synchronizer. The receiver path provides a high degree of linearity, an extended dynamic

range, and high-order on-chip channel filtering to ensure reliable operation in the noisy 2.4 GHz ISM band. The

front-end topology with built-in out-of-band attenuation enables the BCM4354 to be used in most applications

with minimal off-chip filtering. For integrated handset operation, in which the Bluetooth function is integrated

close to the cellular transmitter, external filtering is required to eliminate the desensitization of the receiver by

the cellular transmit signal.

Digital Demodulator and Bit Synchronizer

The digital demodulator and bit synchronizer take the low-IF received signal and perform an optimal frequency

tracking and bit synchronization algorithm.

Receiver Signal Strength Indicator

The radio portion of the BCM4354 provides a Receiver Signal Strength Indicator (RSSI) signal to the baseband,

so that the controller can take part in a Bluetooth power-controlled link by providing a metric of its own receiver

signal strength to determine whether the transmitter should increase or decrease its output power.

Local Oscillator Generation

Local Oscillator (LO) generation provides fast frequency hopping (1600 hops/second) across the 79 maximum

available channels. The LO generation subblock employs an architecture for high immunity to LO pulling during

PA operation. The BCM4354 uses an internal RF and IF loop filter.

Calibration

The BCM4354 radio transceiver features an automated calibration scheme that is fully self contained in the

radio. No user interaction is required during normal operation or during manufacturing to provide the optimal

performance. Calibration optimizes the performance of all the major blocks within the radio to within 2% of

optimal conditions, including gain and phase characteristics of filters, matching between key components, and

key gain blocks. This takes into account process variation and temperature variation. Calibration occurs

transparently during normal operation during the settling time of the hops and calibrates for temperature

variations as the device cools and heats during normal operation in its environment.

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