DE910 Series Hardware User Guide
1vv0300951 Rev.9 – 2015-05-11
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Reserved. Page 56 of 77
10.6.
RTC Bypass Output
The VRTC pin brings out the Real Time Clock supply, which is separate from the rest of the
digital part, allowing only RTC to be active when all the other parts of the device are off. To
this power output a backup capacitor can be added in order to increase the RTC autonomy
during power off of the battery. No devices must be powered from this pin.
For additional details on the Backup solutions please refer to the related application note
(xE910 RTC Backup Application Note).
VRTC also supplies reference power to help DE910 check the time from SMPL (Sudden
Momentary Power Loss).
So it is recommended as best practice to connect VRTC to a shunt capacitor (VRTC to GND)
and the acceptable capacitor value is:
Parameter
Min
Keep-alive capacitor
on Pad no. = C14
6.8uF
NOTE:
SMPL (Sudden Momentary Power Loss) : SMPL feature initiates a power-on sequence if the
monitored system voltage; VBATT drops out of range and then returns in range within a
programmable interval. SMPL achieves immediate and automatic recovery from momentary
power loss such as a brief battery disconnect.
NOTE:
VBATT must be supplied in order to use RTC function.
NOTE:
It is recommended to add a keep-alive capacitor on VRTC.
WARNING:
NO devices must be powered from this pin.
