Reference Manual

16 Design in guide
16.1 Advice for schematic and layout
For users with less RF experience it is advisable to closely copy the relating evaluation
board with respect to schematic and layout, as it is a proven design. The layout should
be conducted with particular care, because even small deficiencies could affect the radio
performance and its range or even the conformity.
The following general advice should be taken into consideration:
• A clean, stable power supply is strongly recommended. Interference, especially oscil-
lation can severely restrain range and conformity.
• Variations in voltage level should be avoided.
• LDOs, properly designed in, usually deliver a proper regulated voltage.
• Blocking capacitors and a ferrite bead in the power supply line can be included to filter
and smoothen the supply voltage when necessary.
No fixed values can be recommended, as these depend on the circumstances
of the application (main power source, interferences etc.).
The use of an external reset IC should be considered if one of the following
points is relevant:
• The slew rate of the power supply exceeds the electrical specifications.
• The effect of different current consumptions on the voltage level of bat-
teries or voltage regulators should be considered. The module draws
higher currents in certain scenarios like start-up or radio transmit which
may lead to a voltage drop on the supply. A restart under such circum-
stances should be prevented by ensuring that the supply voltage does
not drop below the minimum specifications.
• Voltage levels below the minimum recommended voltage level may lead
to misfunction. The /Reset pin of the module shall be held on LOW logic
level whenever the VCC is not stable or below the minimum operating
Voltage.
• Special care must be taken in case of battery powered systems.
Proteus-III reference manual version 0.11 © November 2019
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