TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R07
Advance Information
Design-in
Page 120 of 158
2.9
Mini PCIe specific signals (W_DISABLE#, LED_WWAN#)
Mini PCI Express specific signals (
W_DISABLE#
,
LED_WWAN#
) are not available on TOBY-L2 series.
2.9.1.1
Guidelines for W_DISABLE# circuit design
As described in Figure 68, the MPCI-L2 series modules
W_DISABLE#
wireless disable input is equipped with an
internal pull-up to the
3.3Vaux
supply: an external pull-up resistor is not required and should not be provided.
If connecting the
W_DISABLE#
input to a push button, the pin will be externally accessible on the application
device. According to EMC/ESD requirements of the application, an additional ESD protection device should be
provided close to accessible point, as described in Figure 68 and Table 43.
ESD sensitivity rating of the
W_DISABLE#
pin is 1 kV (HBM according to JESD22-A114). Higher protection
level can be required if the line is externally accessible on the application board, e.g. if an accessible push
button is directly connected to the
W_DISABLE#
pin, and it can be achieved by mounting an ESD
protection (e.g. EPCOS CA05P4S14THSG varistor) close to accessible point.
An open drain output is suitable to drive the
W_DISABLE#
input from an application processor as it is equipped
with an internal pull-up to the
3.3Vaux
supply as described in Figure 68.
A compatible push-pull output of an application processor can also be used. In any case, take care to set the
proper level in all the possible scenarios to avoid an inappropriate disabling of the radio operations.
MPCI-L2 series
3.3Vaux
20
W_DISABLE#
Power-on
push button
ESD
Open
Drain
Output
Application
Processor
MPCI-L2 series
3.3Vaux
20
W_DISABLE#
TP
TP
22 k
22 k
Figure 68: W_DISABLE# application circuit using a push button and an open drain output of an application processor
Reference
Description
Remarks
ESD
Varistor for ESD protection
CT0402S14AHSG - EPCOS
Table 43: Example of ESD protection component for the W_DISABLE# application circuit
If the
W_DISABLE#
functionality is not required by the application, the pin can be left unconnected.