Texas Instruments 3138 155 232931 - Manual (Page 18)

CC2420
SWRS041B Page 18 of 89
and Q LO signals to the down-conversion
mixers in receive mode and up-conversion
mixers in transmit mode. The VCO
operates in the frequency range 4800 –
4966 MHz, and the frequency is divided by
two when split in I and Q.
A crystal must be connected to
XOSC16_Q1
and XOSC16_Q2 and
provides the reference frequency for the
synthesizer. A digital lock signal is
available from the PLL.
The digital baseband includes support for
frame handling, address recognition, data
buffering and MAC security.
The 4-wire SPI serial interface is used for
configuration and data buffering.
An on-chip voltage regulator delivers the
regulated 1.8 V supply voltage. The
voltage regulator may be enabled /
disabled through a separate pin.
A battery monitor may optionally be used
to monitor the unregulated power supply
voltage. The battery monitor is
configurable through the SPI interface.