SIM800C datasheet(37/52 Pages) SIMCOM

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Smart Machine Smart Decision

SIM800C_Hardware_Design_V1.02

2015-4-27

Pin name

Pin number

Mode 0(default)

Mode 1

RF_SYNC

RF Synchronization Signal

JD（RF jamming detection）

Note: About AT+SJDR, please refer to document [1].

4.13. Antenna Interface

There are two antenna interfaces, GSM_ANT and BT_ANT.



The input impendence of the antenna should be 50Ω, and the VSWR should be less than 2.



It is recommended that the GSM antenna and the BT antenna should be placed as far as possible.



The isolations of the two antenna should be bigger than 30dB

NOTE：About the RF trace layout please refer to“AN_SMT Module_RF_Reference Design_Guide”.

4.13.1 GSM Antenna Interface

SIM800C provides a GSM antenna named GSM_ANT, customer could use 50Ω microstrip line or stripline

antenna connect to the module.

It is recommended to reserve the matching circuit as following:

Module

GN D

(P in33)

R F connector

R101

GS M _ A N T

C101

C102

GN D

(P in31)

GS M

Antenna

(P in33)

Figure 36: GSM antenna matching circuit

R101，C101，C102 are the matching circuit, the value should be defined by the antenna design. Normally R101 is

0Ω, C101 and C102 are not mounted.

The RF connector is used for conduction test. If the space between RF pin and antenna is not enough, the

matching circuit should be designed as in the following figure:

M odule

R101

GS M _A N T

C101

C102

GN D

(P in33)

GN D

(P in31)

GS M

Antenna

(P in33)

Figure 37: GSM antenna matching circuit without RF connector

SIM800C Datasheet(PDF) 37 Page - SIMCom

SIM800C Datasheet(HTML) 37 Page - SIMCom

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