SARA-N2 / N3 series - System integration manual
UBX-17005143 - R13
System description
Page 17 of 95
C1-Public
1.5.3
Interfaces supply output (V_INT)
The same voltage domain internally used as supply for the generic digital interfaces of SARA-N2 / N3
series modules is also available on the
V_INT
output pin, as illustrated in
In detail, the
V_INT
supply rail is used internally to supply the:
•
I2C interface, and the GPIO pins of SARA-N2 series modules
•
UART interfaces, the I2C interface, and the GPIO pins of SARA-N3 series modules
The internal regulator that generates the
V_INT
supply output is a low drop out (LDO) converter, which
is directly supplied from the
VCC
main supply input of the module.
The
V_INT
supply output provides internal short circuit protection to limit start-up current and
protect the load to short circuits.
The
V_INT
voltage regulator output of SARA-N2 series modules is disabled (i.e. 0 V) when the module
is switched off, and it can be used to monitor the operating mode when the module is switched on:
•
When the radio is off, the voltage level is low (i.e. 0 V)
•
When the radio is on, the voltage level is high (i.e. 1.8 V)
The
V_INT
voltage regulator output of SARA-N3 series modules is disabled (i.e. 0 V) when the module
is switched off, and it can be used to monitor the operating mode of the module as follows:
•
When the module is off, or in deep sleep mode, the voltage level is low (i.e. 0 V)
•
When the module is on, outside deep sleep mode, the voltage level is high (i.e. 1.8 V or 2.8 V)
The
V_INT
operating voltage of SARA-N3 series modules can be selected using the
VSEL
input pin:
•
If the
VSEL
input pin is connected to
GND
, the digital I/O interfaces operate at 1.8 V
•
If the
VSEL
input pin is left unconnected, the digital I/O interfaces operate at 2.8 V
☞
If the
VSEL
input pin is left unconnected, the
VCC
voltage shall be inside normal operating range
to let the digital I/O interfaces work correctly (see SARA-N3 series data sheet
for more details).
☞
Provide a test point connected to the
V_INT
pin for diagnostic purpose.
Baseband
processor
51
VCC
52
VCC
53
VCC
4
V_INT
LDO
Digital I/O
interfaces
Power
management
SARA-N2/N3 series
Figure 6: SARA-N2 / N3 series interfaces supply output (V_INT) simplified block diagram
