Hardware Manual

 A protection diode must be inserted close to the power input, in order to save
HE910 V2 from power polarity inversion. This can be the same diode as for spike
protection.
An example of switching regulator with 12V input is in the schematic below:
The desired nominal output for the power supply is 3.8V and the maximum voltage allowed is
4.2V. A single 3.7V lithium-ion cell battery type is ideal to supply power to the Telit HE910
V2 module.
WARNING:
The three battery cells (Ni/Cd or Ni/MH 3.6V nom. battery types or 4V PB types) MUST
NOT be used directly because their maximum voltage can rise over the absolute maximum
voltage for the HE910 V2 and cause damage. USE only Li-Ion battery types.
NOTE:
Do not use any Ni-Cd, Ni-MH, and Pb battery types directly connected with HE910 V2. Their
use can lead to overvoltage on HE910 V2 and damage it. Use only Li-Ion battery types.
 A Bypass low ESR capacitor of adequate capacity must be provided in order to
cut the current absorption peaks, a 100μF tantalum capacitor is usually suited.
 Make sure the low ESR capacitor (usually a tantalum one) is rated at least 10V.