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AIROC™ Bluetooth® LE module
Connections and optional external components
5
Connections and optional external components
5.1
Power connections (VDDIN)
The CYBLE-3x307x-02 contains one power supply connection, VDDIN, which accepts a supply input range of 2.5 V
to 3.6 V for CYBLE-3x307x-02.
power connection is 100 mV, as shown in
It is not required to place any power supply decoupling or noise reduction circuitry on the host PCB. If desired,
an external ferrite bead between the supply and the module connection can be included, but is not necessary. If
used, the ferrite bead should be positioned as close as possible to the module pin connection and the recom-
mended ferrite bead value is 330 , 100 MHz.
Considerations and Optional Components for Brown Out (BO) Conditions
Power supply design must be completed to ensure that the CYBLE-3x307x-02 module does not encounter a
Brown Out condition, which can lead to unexpected functionality, or module lock up. A Brown Out condition may
be met if power supply provided to the module during power up or reset is in the following range:
Refer to
Table 13
for the V
System design should ensure that the condition above is not encountered when power is removed from the
system. In the event that this cannot be guaranteed (that is, battery installation, high-value power capacitors
with slow discharge), it is recommended that an external voltage detection device be used to prevent the Brown
Out voltage range from occurring during power removal. Refer to
when using an external voltage detection IC.
Figure 8
Reference circuit block diagram for external voltage detection IC
In the event that the module does encounter a Brown Out condition, and is operating erratically or is not
responsive, power cycling the module will correct this issue and once reset, the module should operate correctly.
Brown Out conditions can potentially cause issues that cannot be corrected, but in general, a power-on-reset
operation will correct a Brown Out condition.
5.2
External reset (XRES)
The CYBLE-3x307x-02 has an integrated power-on reset circuit, which completely resets all circuits to a known
power-on state. This action can also be evoked by an external reset signal, forcing it into a power-on reset state.
The XRES signal is an active-low signal, which is an input to the CYBLE-3x307x-02 module (solder pad 3). The
CYBLE-3x307x-02 module does not require an external pull-up resistor on the XRES input
During power-on operation, the XRES connection to the CYBLE-3x307x-02 is required to be held low 50 ms after
the VDD power supply input to the module is stable. This can be accomplished in the following ways:
• The host device should connect a GPIO to the XRES of the CYBLE-3x307x-02 module and pull XRES low until VDD
is stable. XRES is recommended to be released 50 ms after VDDIN is stable.
Preliminary Datasheet
Table 12
provides this specification. The maximum power supply ripple for this
Table
12.
V
IL
and V
specifications.
IL
IH
VDDIN
V
IH
Figure 8
17 of 58
for the recommended circuit design
002-33419 Rev. **
2021-07-22
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