PRELIMINARY
CYW20713
6.2 Crystal Oscillator
The CYW20713 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 6.
Figure 6. Recommended Oscillator Configuration
XIN
0 to 18 pF*
Crystal
Oscillator
XOUT
0 to 18 pF*
*Capacitor value range depends on the
manufacturer of the XTAL as well as board layout.
6.3 External Frequency Reference
An external frequency reference generated by a TCXO signal that may be directly connected to the crystal input pin on the CYW20713,
as shown in Figure 7. The external frequency reference input is designed to not change loading on the TCXO when the CYW20713
is powered up or powered down.
When using the CYW20713 with the TXCO OR gate option, GPIO 6 must be driven active high or active low. Excessive leakage
current results if GPIO6 is allowed to float.
Figure 7. Recommended TCXO Connection
TCXO
XIN
10–1000 pF*
XOUT
No Connection
* Recommended value is 100 pF.
Higher values produce a longer startup time.
Lower values have greater isolation.
Larger values help small signal swings.
6.3.1 TCXO Clock Request Support
If the application utilizes an external TCXO as a clock reference, the CYW20713 provides a clock request output to allow the system
to power off the TCXO when not in use. Optionally, some packages support a TCXO OR function that allows a clock request in the
system to be combined with the CYW20713 clock request output, without requiring an extra component on the board.
Document Number: 002-14806 Rev. *C
Page 21 of 52
CYPRESS [ CYPRESS ]
