PRELIMINARY
CYW43364
3. Frequency References
An external crystal is used for generating all radio frequencies and normal operation clocking. As an alternative, an external frequency
reference driven by a temperature-compensated crystal oscillator (TCXO) signal may be used. No software settings are required to
differentiate between the two. In addition, a low-power oscillator (LPO) is provided for lower power mode timing.
3.1 Crystal Interface and Clock Generation
The CYW43364 can use an external crystal to provide a frequency reference. The recommended configuration for the crystal oscillator,
including all external components, is shown in Figure 5. Consult the reference schematics for the latest configuration.
Figure 5. Recommended Oscillator Configuration
C
WLRF_XTAL_XOP
12 – 27 pF
C
WLRF_XTAL_XON
R
12 – 27 pF
Note: Resistor value determined by crystal
drive level. See reference schematics for
details.
The CYW43364 uses a fractional-N synthesizer to generate the radio frequencies, clocks, and data/packet timing so that it can operate
using numerous frequency references. The frequency reference can be an external source such as a TCXO or a crystal interfaced
directly to the CYW43364.
The default frequency reference setting is a 37.4 MHz crystal or TCXO. The signal requirements and characteristics for the crystal
interface are shown in Table 3 on page 12.
Note: Although the fractional-N synthesizer can support many reference frequencies, frequencies other than the default require
support to be added in the driver, plus additional extensive system testing. Contact Cypress for further details.
Document Number: 002-14781 Rev. *C
Page 11 of 68
CYPRESS [ CYPRESS ]
