BCM20713A1KUFBXG Datasheet, PDF (33/65 Pages) Cypress Semiconductor – Single-Chip Bluetooth Transceiver and Baseband Processor

BCM20713 Preliminary Data Sheet
External Frequency Reference
Figure 7: Recommended TCXO Connection
TCXO
10–1000 pF*
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.
XIN
XOUT
TCXO Clock Request Support
If the application utilizes an external TCXO as a clock reference, the BCM20713 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 BCM20713 clock request output,
without requiring an extra component on the board.
Clock Request Output
The CLK_REQ signal on the GPIO_5 lead is asserted whenever the BCM20713 is in the Awake state. It is
deasserted when in Sleep state. When the BCM20713 is sleeping, it uses an LPO clock (external or internal) as
the timing reference.
The TM0 lead controls the polarity of the CLK_REQ output on GPIO_5 as follows:
TM0 = 0
CLK_REQ is active low
TM0 = 1
CLK_REQ is active high
If the clock request feature is not desired, GPIO_5 can be configured for other functions.
TCXO OR Option
The BCM20713 has an optional feature that allows the application to perform a logical OR function on a system
TCXO clock request signal and the BCM20713 clock request to form one clock request output to the TCXO
device. This logical OR function is embedded in the pad ring so that it is available at any time, as long as the
pad ring is receiving a VDDO supply. The function works even if the BCM20713’s digital core is sleeping or
completely powered off.
To use this feature, the TCXO_MODE lead must be tied high. In this mode, the GPIO_6 lead functions as the
external clock request input. Without TCXO_MODE asserted, GPIO_5 functions as the clock request output
(based only on the internal clock requirements of the BCM20713) and the state of GPIO_6 is ignored.
Broadcom^®
December 21, 2015 • 20713-DS102-R
Single-Chip Bluetooth Transceiver and Baseband Processor
Page 32
BROADCOM CONFIDENTIAL