Integration Manual

Table Of Contents
TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R26 Design-in
Page 84 of 162
If the RTC timing is not required when the VCC supply is removed, it is not needed to connect the V_BCKP
pin to an external capacitor or battery. In this case the date and time are not updated when VCC is
disconnected. If VCC is always supplied, then the internal regulator is supplied from the main supply and
there is no need for an external component on V_BCKP.
V_BCKP supply output pin provides internal short circuit protection to limit start-up current and protect the device
in short circuit situations. No additional external short circuit protection is required.
Do not apply loads which might exceed the limit for maximum available current from V_BCKP supply (see
TOBY-L2 series Data Sheet [1]) as this can cause malfunctions in internal circuitry.
ESD sensitivity rating of the V_BCKP supply pin is 1 kV (Human Body Model according to JESD22-A114).
Higher protection level could be required if the line is externally accessible and it can be achieved by
mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to the accessible point.
2.2.2.2 Guidelines for V_BCKP layout design
V_BCKP supply requires careful layout: avoid injecting noise on this voltage domain as it may affect the stability
of the internal circuitry.