User's Manual

LE920 Hardware User Guide
1vv0301026 Rev.8 2015-01-03
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 67 of 88
12.6. RTC Bypass
The VRTC pin brings out the Real Time Clock supply, which is separate from the rest of the
digital part, allowing having only the RTC operating when all the other parts of the device are
turned off.
If maintaining internal RTC block is needed, it recommended to connect a backup capacitor
or a coin cell to this pin (valid range from 2.5V to 3.2V), otherwise, it can be left unconnected
Operating Modes:
1. LE920 has a valid VBAT supply, and the unit is turned ON – RTC block supply will be
generated from main VBAT supply, and the VRTC pin will output the VRTC supply,
charging external coin cell or capacitor.
2. LE920 has no VBAT connected – The External coin cell or capacitor will maintain
VRTC supply, keeping the internal RTC unit block operational.
NOTE:
NO devices may be powered from this pin.
12.7. VAUX Power Output
A regulated power supply output is provided in order to supply small devices from the
module. This output is active when the module is ON and goes OFF when the module is shut
down. The operating range characteristics of the supply are:
Operating Range – VAUX power supply
Min
Typical
Max
Output voltage
1.75V
1.80V
1.85V
Output current
100mA
Output bypass capacitor
(Inside the module)
1μF