SimCom SIM7000 Hardware Design page 44

RF Antenna
TVS
LXES15AAA 1-153
R 101 0 R
NC
C 106
Power supply
VBAT
C 101 C 102
C 103
100 uF 100 uF 100 uF
R 102
4 . 7 K
Turn on / off impulse
R 103
R 105 4 . 7 K
Turn on / off impulse
R 106
UART _ TXD
UART _ RXD
UART _ CTS
UART _ RTS
UART _ RI
UART _ DCD
UART _ DTR
SIM _DATA SIM _ CLK
SIM_RST
SIM _VDD
C 109
220 nF
TVS
ESDA 6 V 1 W 5
Test Point
VDD _ EXT
LDO Output : 1. 8 V
Test Point
Test Point
In above figures, the components C1, L1 and L2 are used for antenna matching. Usually, the values
of the components can only be achieved after antenna tuning and usually provided by antenna
vendor. C2 is used for DC blocking. L3 is the matching component of the external LNA, and the
value of L3 is determined by the LNA characteristic and PCB layout. Both VDD of active antenna
and V_LNA need external power supplies which should be considered according to active antenna
and LNA characteristic. LDO/DCDC is recommended to get lower current consuming by shutting
down active antennas and LNA when GNSS is not working.
GNSS can be tested by NMEA port. NMEA sentences can be obtained through UART or USB
automatically. NMEA sentences include GSV, GGA, RMC, GSA, and VTG. Before using GNSS,
user should configure SIM7000 in proper operating mode by AT command. Please refer to related
documents for details. SIM7000 can also get position location information through AT directly.
Note:
1. GNSS is closed by default and can be started by "AT+CGNSPWR=1". The AT command has
two parameters, the first is on/off, and the second is GNSS mode. Default mode is standalone
mode.
AGPS mode needs more support from the mobile telecommunication network. Please refer to
document [21] for more details.
2. If the passive antenna is used, put the LNA close to the antenna.
3. Make sure there are no noise signals around GNSS antenna.
SIM7000 _Hardware Design _V1.04
60 RF _ ANT
NC
61
C 107 GND
62
GND
63 GND
55 VBAT
VBAT
56
C 104
GND
57
1 uF
GND
58
GND
59
1 POWERKEY
SIM7000
47 K
16
NRESET
47 K
9
TXD
RXD
10
7
CTS
8
RTS
4 RI
5 DCD
3 DTR
31
USIM _ DATA
32
USIM _ CLK
33
USIM _ RST
30
USIM_ VDD
34 USIM _DET
15
VDD _ EXT
6
BOOT _ CFG
23
MDM _ LOG _ TX
2
GND
17
GND
18
GND
29
GND
39
GND
45
GND
46
GND
64
GND
65
GND
Figure 28: Passive antenna circuit (Default)
Smart Machine Smart Decision
GNSS
53
GNSS_ ANT
C 108
L 101
33pF
NC
54
GND
R 108 4. 7 K
NETLIGHT 52
R 107
47 K
R 110 4. 7K
STATUS 66
R 112
47 K
38
I 2 C_ SCL
37
I 2 C_ SDA
25
ADC
Input range : 0 . 1~1 . 7 V
24
USB_VBUS USB _ VBUS
28
USB _ DN USB _ DN
27
USB _ DP USB_ DP
13
PCM _DIN
12
PCM _ SYNC Audio CODEC
14
PCM _DOUT
or
11
PCM _CLK
DSP
50
GPIO 0/ UART3_ TXD
GPIO 1/ UART3_RXD 49
68
GPIO2
67
GPIO3
48
GPIO4
19
NC
20
NC
21
NC
22
NC
26
NC
35
NC
36
NC
40
NC
41
NC
42
NC
43
NC
44
NC
47
NC
51
NC
Antenna
L 102
NC
LED
R 109
VBAT
Power supply
510R
LED
R 111
VBAT
Power supply
510 R
VDD _ EXT
I 2 C_ SCL
I 2 C_ SDA
ADC
2018-1-31