User's Manual

Document Number: 002-19525 Rev. ** Page 18 of 49
PRELIMINARY
CYBT-343026-01
CYBT-343029-01
CYBT-143038-01
Integrated Radio Transceiver
The CYBT-X430XX-01 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 CYBT-X430XX-01 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.
Transmitter Path
The CYBT-X430XX-01 a fully integrated z6ro-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 π/4-DQPSK for 2 Mbps and 8-DPSK for 3 Mbps to support
EDR. The transmitter section is compatible with the BLE 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, π/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 bitsyn-
chronization 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 integrated mobile handset appli-
cations 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 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, with built-in out-of-band attenuation,
enables the CYBT-X430XX-01 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 CYBT-X430XX-01 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.
Local Oscillator Generation
The local oscillator (LO) 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 CYBT-X430XX-01 uses an
internal loop filter.
Calibration
The CYBT-X430XX-01 radio transceiver features an auotmated calibration scheme that is fully self-contained in the radio. No user
interaction is required during normal operation or during manufacturing to provide optimal performance. Calibration tunes the perfor-
mance 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..