User's Manual

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L850-GL Hardware User Manual Page
22
of
51
Recommended
capacitance
Application
Description
39pF,33pF
700/800, 850/900
MHzfrequency band
Filter out low frequency band RF interference
18pF,8.2pF,6.8pF
1500/1700/1800/1900,2100/
2300,2500/2600MHzfrequen
cy band
Filter out medium/high frequency band RF
interference
The stable power supply can ensure the normal operation of L850 module;and the ripple of the power
supply should be less than 300mV in design. When the module operates with themaximum emission
power, the maximum operating current can reach 1000mA, so the power source should be not lower than
3.135V, or the module may shut down or reboot. The power supply limits are shown in Figure 3-3:
Figure 3-3 Power Supply Limit
3.2.2 Logic level
The L850module 1.8V logic level definitionas shown in the following table:
Parameters
Minimum
Typical
Maximum
Unit
1.8V logic level
1.71
1.8
1.89
V
V
IH
1.3
1.8
1.89
V
V
IL
-0.3
0
0.5
V
The L850module 3.3V logic level definition as shown in the following table:
Parameters
Minimum
Typical
Maximum
Unit
3.3V logic level
3.135
3.3
3.465
V
V
IH
2.3
3.3
3.465
V
V
IL
-0.3
0
0.9
V