BCM88335 Data Sheet
Bluetooth Radio
Power Amplifier
The fully integrated PA supports Class 1 or Class 2 output using a highly linearized, temperature-compensated
design. This provides greater flexibility in front-end matching and filtering. Due to the linear nature of the PA
combined with some integrated filtering, external filtering is required to meet the Bluetooth and regulatory
harmonic and spurious requirements. For integrated telematics applications in which Bluetooth is integrated
next to the cellular radio, external filtering can be applied to achieve near-thermal-noise levels for spurious and
radiated noise emissions. The transmitter features a sophisticated on-chip transmit signal strength indicator
(TSSI) block to keep the absolute output power variation within a tight range across process, voltage, and
temperature.
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 BCM88335 to be used in most applications
with minimal off-chip filtering. For integrated telematics 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 BCM88335 provides a Receiver Signal Strength Indicator (RSSI) signal to the
baseband, so that the controller can 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 BCM88335 uses an internal RF and IF loop filter.
Calibration
The BCM88335 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 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.
Broadcom®
September 23, 2015 • 88335-DS100-R
Page 33
BROADCOM CONFIDENTIAL
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