SARA-G450 - System integration manual
UBX-18046432 - R08
Design-in
Page 72 of 143
C1-Public
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If the V_INT supply output is not required by the customer application, the V_INT pin can be left
unconnected.
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It is recommended to provide on the application board a directly accessible Test-Point connected
to the V_INT pin for diagnostic purpose.
2.2.3.2
Guidelines for V_INT layout design
There are no specific layout design recommendations for V_INT output.
2.3
System functions interfaces
2.3.1
Module power-on (PWR_ON)
2.3.1.1
Guidelines for PWR_ON circuit design
Connecting the PWR_ON input to a push button that shorts the PWR_ON pin to GND, the pin will be
externally accessible on the application device: according to EMC/ESD requirements of the
application, provide an additional ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) on the
line connected to this pin, close to accessible point, as described in
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The ESD sensitivity rating of the PWR_ON pin is 1 kV (HBM according to JESD22-A114). A 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 PWR_ON pin. A higher protection level can be
achieved by mounting an ESD protection (e.g. EPCOS CA05P4S14THSG) close to accessible points
When connecting the PWR_ON input to an external device (e.g. application processor), use an open
drain output on the external device, as described in
A compatible push-pull output of an application processor can be used too.
The PWR_ON input voltage thresholds are different from the other generic digital interfaces of the
module: see the SARA-G450 data sheet
for detailed electrical characteristics.
Take care to fix the correct level in all the possible scenarios to avoid an inappropriate module
switch-on.
1:1 scaling
SARA-G450
15
PWR_ON
Power-on
push button
ESD
Open drain
output
Application
Processor
SARA-G450
15
PWR_ON
TP
TP
Figure 33: PWR_ON application circuits using a push button and an open drain output of an application processor
Reference
Description
Part Number - Manufacturer
ESD
Varistor array for ESD protection
CT0402S14AHSG - EPCOS
Table 22: Example of ESD protection for the PWR_ON application circuit
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It is recommended to provide on the application board a directly accessible Test-Point connected
to the PWR_ON pin for diagnostic purpose.
