BCM20706 Data Sheet
Integrated Radio Transceiver
Integrated Radio Transceiver
The BCM20706 has an integrated radio transceiver that has been optimized for use in 2.4 GHz Bluetooth
wireless systems. It has been designed to provide low-power, low-cost, robust communications for applications
operating in the globally available 2.4 GHz unlicensed ISM band. The BCM20706 is fully compliant with the
Bluetooth Radio Specification and enhanced data rate (EDR) specification and meets or exceeds the
requirements to provide the highest communication link quality of service.
Transmit
The BCM20706 features a fully integrated zero-IF transmitter. The baseband transmit data is GFSK-modulated
in the modem block and upconverted to the 2.4 GHz ISM band in the transmitter path. The transmitter path
consists of signal filtering, I/Q upconversion, output power amplifier, and RF filtering. The transmitter path also
incorporates /4-DQPSK for 2 Mbps and 8-DPSK for 3 Mbps to support EDR. The transmitter section is
compatible to the Bluetooth Low Energy specification. The transmitter PA bias can also be adjusted to provide
Bluetooth class 1 or class 2 operation.
Digital Modulator
The digital modulator performs the data modulation and filtering required for the GFSK, /4-DQPSK, and
8-DPSK signal. The fully digital modulator minimizes any frequency drift or anomalies in the modulation
characteristics of the transmitted signal and is much more stable than direct VCO modulation schemes.
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.
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 applications in which Bluetooth is integrated next to other radios such
as 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.
Broadcom®
Bluetooth SoC
May 19, 2016 • 20706-DS202-R
Page 13
BROADCOM CONFIDENTIAL
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