ADVANCE
CYW43570
■ Full support for power savings modes
❐ Bluetooth clock request
❐ Bluetooth standard sniff
❐ Deep-sleep modes and software regulator shutdown
■ TCXO input and auto-detection of all standard handset clock frequencies. Also supports a low-power crystal, which can be used
during power save mode for better timing accuracy.
■ Improved audio interface capabilities with full-featured bidirectional PCM and I2S
■ I2S can be master or slave
4.2 Bluetooth Radio
The CYW43570 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. It is fully compliant with the Bluetooth Radio Specification and EDR specification and meets or exceeds the
requirements to provide the highest communication link quality of service. An integrated T/R switch combines Bluetooth transmit and
receive paths, and connects directly to a dedicated Bluetooth antenna.
4.2.1 Transmit
The CYW43570 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.
4.2.2 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 trans-
mitted signal and is much more stable than direct VCO modulation schemes.
4.2.3 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.
4.2.4 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 PAcombined 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.
4.2.5 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 CYW43570 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.
Document Number: 002-15054 Rev. *I
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