CYW20732A0
1.7 Integrated Radio Transceiver
The CYW20732 has an integrated radio transceiver that is optimized for 2.4 GHz Bluetooth wireless systems. It has been designed
to provide low power, low cost, and robust communications for applications operating in the globally available 2.4 GHz unlicensed
ISM band. It is fully compliant with Bluetooth Radio Specification 4.0 and meets or exceeds the requirements to provide the highest
communication link quality of service.
1.7.1 Transmitter Path
The CYW20732 features a fully integrated transmitter. The baseband transmit data is GFSK modulated in the 2.4 GHz ISM band.
1.7.2 Digital Modulator
The digital modulator performs the data modulation and filtering required for the GFSK signal. The fully digital modulator minimizes
any frequency drift or anomalies in the modulation characteristics of the transmitted signal.
1.7.3 Power Amplifier
The CYW20732 has an integrated power amplifier (PA) that can transmit up to +4 dBm for class 2 operation.
1.7.4 Receiver Path
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, which has built-in out-of-band attenuation,
enables the CYW20732 to be used in most applications without off-chip filtering.
1.7.5 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.
1.7.6 Receiver Signal Strength Indicator
The radio portion of the CYW20732 provides a receiver signal strength indicator (RSSI) to the baseband. This enables the controller
to 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.
1.7.7 Local Oscillator
The local oscillator (LO) provides fast frequency hopping (1600 hops/second) across the 79 maximum available channels. The
CYW20732 uses an internal loop filter.
1.7.8 Calibration
The CYW20732 radio transceiver features a self-contained automated calibration scheme. No user interaction is required during
normal operation or during manufacturing to provide optimal performance. Calibration compensates for filter, matching network, and
amplifier gain and phase characteristics to yield radio performance within 2% of what is optimal. Calibration takes process and
temperature variations into account, and it takes place transparently during normal operation and hop setting times.
1.7.9 Internal LDO Regulator
The CYW20732 has an integrated 1.2V LDO regulator that provides power to the digital and RF circuits. The 1.2V LDO regulator
operates from a 1.425V to 3.63V input supply with a 30 mA maximum load current.
Note: Always place the decoupling capacitors near the pins as closely together as possible.
1.8 Peripheral Transport Unit
1.8.1 Cypress Serial Communications Interface
The CYW20732 provides a 2-pin master BSC interface, which can be used to retrieve configuration information from an external
EEPROM or to communicate with peripherals such as track-ball or touch-pad modules, and motion tracking ICs used in mouse
devices. The BSC interface is compatible with I2C slave devices. The BSC does not support multimaster capability or flexible wait-
state insertion by either master or slave devices.
The following transfer clock rates are supported by the BSC:
■ 100 kHz
■ 400 kHz
■ 800 kHz (not a standard I2C-compatible speed.)
Document Number: 002-14837 Rev. *L
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