Fibocom L831-EAU-01 - Logic Level Definition

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L831-EAU-01 Hardware User Manual Page
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The filter capacitor design for power supply as shown in the following table:
Recommended
capacitance
Application
Description
220uF
Voltage-stabilizing
capacitors
Reduce power fluctuations of the module in
operation, requiring capacitors with low ESR.
 LDO or DC/DC power supply requires the
capacitor of no less than 220uF
 The capacitor for battery power supply can be
reduced to 100uF
1uF,100nF
Digital signal noise
Filter out the interference generated from the clock
and digital signals
39pF
900 MHz frequency band
Filter out low frequency band RF interference
18pF,8.2pF,6.8pF
1800/1900,2100/2300,2500
/2600MHz frequency band
Filter out medium/high frequency band RF
interference
The stable power supply can ensure the normal operation of L831-EAU module; and the ripple of the
power supply should be less than 300mV in design. When the module operates under maximum
transmitted power, the maximum operating current can reach 750mA, so the power source should be not
lower than 3.0V, or the module may shut down or reboot.
3.2.2 Logic level
The L831-EAU module 1.8V logic level definition as 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 L831-EAU module 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