SARA-R5 series - System integration manual
UBX-19041356 - R04 Design-in Page 96 of 118
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2.13 Design-in checklist
This section provides a design-in checklist.
2.13.1 Schematic checklist
The following are the most important points for a simple schematic check:
DC supply must provide a nominal voltage at VCC pin within the operating range limits.
DC supply must be capable of supporting the highest peak / pulse current consumption values
and the maximum averaged current consumption values in connected mode, as specified in the
SARA-R5 series data sheet [1].
VCC voltage supply should be clean, with very low ripple/noise: provide the suggested bypass
capacitors, in particular if the application device integrates an internal antenna.
Do not apply loads which might exceed the limit for maximum available current from V_INT supply.
Check that voltage level of any connected pin does not exceed the relative operating range.
Provide accessible test points directly connected to the V_INT, PWR_ON and RESET_N pins of the
SARA-R5 series modules for diagnostic purposes.
Capacitance and series resistance must be limited on each SIM signal to match the SIM
specifications.
Insert the suggested pF capacitors on each SIM signal and low capacitance ESD protections if
accessible.
Check UART signals direction, considering the modules’ signal names follow the ITU-T V.24
recommendation [5].
Provide accessible test points directly connected to the TXD and RXD pins of the SARA-R5 series
modules for FW update purpose and to the DCD and DTR pins for diagnostic purpose, in particular
providing a 0 series jumper on each line to detach each pin of the module from the DTE
application processor.
Provide accessible test points directly connected to the VUSB_DET, USB_D+ and USB_D- pins of
the SARA-R5 series modules for diagnostic purposes.
Use transistors with at least an integrated resistor in the base pin or otherwise put a 10 k resistor
on the board in series to the GPIO when those are used to drive LEDs.
Provide adequate precautions for EMC / ESD immunity as required on the application board.
Do not apply voltage to any generic digital interface pin of SARA-R5 series modules before the
switch-on of the generic digital interface supply source (V_INT).
All unused pins can be left unconnected.
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