Download Power Suppply and UART Circuit

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Power Suppply and UART Circuit
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For 3.3V MCU
Customer's MCU
VCC_MCU_3.3V
RXD
RXD_MCU
TXD
TXD_MCU
10K
Q102
MCU_ON/OFF
R104
RXD_MCU
For 5V MCU
R103,R104 are resrved for debugging the waveform of UART,
and they are also beneficial to ESD protection.
DTC143ZEBTL
RXD_MCU
RXD
GND
XC6209E332MR
MCU_ON/OFF
4
R106
4.7K
1K
NC
CE
C106
MCU_ON/OFF
GND
R105
GPIO_X
3
MCU
R108
4.7K
RXD1_MODULE
TXD_MCU
B
R110
4.7K
R109
4.7K
RXD_MCU
TXD1_MODULE
Q104
Q103
TXD_MCU
TXD
R107
4.7K
VCC_MODULE_3.3V
VCC_MODULE_3.3V
5
D102
FORCE_ON
100nF
VOUT
C105
GPIO_X
100uF
2
100nF
GPIO_RESET
C104
4.7uF
GPIO_X
+
C103
U102
VIN
VCC_MCU_5V
U103
1
VCC_MCU_5V
VCC_MODULE_3.3V
VCC_MCU_5V
Customer's MCU
VCC
C
Level Shifting for UART
LDO Circuit
VCC_MCU_5V
TXD1_MODULE
Generally,100R for R103 and R104 is recommended,but 0R also works well.
MCU
B
100R
1K
MCU_ON/OFF
C102
GPIO_X
R101
R102
FORCE_ON
100nF
GPIO_X
RXD1_MODULE
100R
VCC_MODULE_3.3V
SI2333DS
D101
GPIO_RESET
C101
GPIO_X
GND
C
R103
TXD_MCU
4.7uF
VCC
UART Circuit
Power ON/OFF Circuit
Q101
U101
VCC_MCU_3.3V
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The transistor circuit will realize the voltage level shifting between
VCC_MCU_5V and VCC_MODULE_3.3V, and block the leakage
current from one power-on device to another power-off device.
Quectel Wireless Solutions
A
DRAWN BY
<King HAO>
CHECKED BY
<Ray XU>
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PORJECT
<L26>
SIZE
TITLE
<L26_Reference_Design>
VER
<1.01>
A2
SHEET 1 of 3
<2013.05>
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Module Interface
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Module Interface
Test Points
U201
ANTON
R203
R204
TXD1_MODULE
RXD1_MODULE
V_BCKP
VCC_MODULE_3.3V
C
C201
C202
10uF
100nF
NM
NM
13
14
15
16
17
18
19
20
21
22
23
24
GND
ANT_ON
RESERVED
RESERVED
NC
RESERVED
RESERVED
TXD1
RXD1
V_BCKP
VCC
GND
GND
RF_IN
GND
VCC_RF
RESET
NC
V_ANT
AADET_N
RESERVED
1PPS
NC
FORCE_ON
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10
9
8
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RF_IN
VCC_RF
RESET
L26_TXD1
TXD1_MODULE
L26_RXD1
RXD1_MODULE
L26_VCC
GND
V_ANT
AADET_N
VCC_MODULE_3.3V
GND
1. UART1 can be used to output NMEA message as well as to upgrade firmware.
1PPS
C
2. R203,R204 are reserved to modify baud rate for future.
FORCE_ON
Keep R203,R204 unmounted in L26 module.
L26
3. The test points are reserved for module debugging.
Indicating Circuit
VCC_MODULE_3.3V
D
Charging Circuit for RTC logic
Reset Circuit
RESET
D202
VCC_MODULE_3.3V
B
RB520S30T1G
Schottky Diode
D201
GPIO_RESET
R201
1K
1PPS
Q202
V_BCKP
DTC143ZEBTL
Q201
DTC143ZEBTL
The 1PPS indicator will blink at 1Hz frequency
after fixing the position.
B
1K
R202
B201
XH414
C203
4.7uF
C204
100nF
1. If the reset function is unused, the RESET
pin can be connected to the VCC directly.
V_BCKP is designed to supply power for L26 RTC
2. RESET has been pulled up internally.
logic circuit when VCC_MODULE_3.3V is powered off.
Quectel Wireless Solutions
A
DRAWN BY
<King HAO>
CHECKED BY
<Ray XU>
6
5
4
3
2
PORJECT
<L26>
SIZE
A2
SHEET
2 of 3
TITLE
<L26_Reference_Design>
VER
<1.01>
<2013.05>
1
A
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Antenna Interface
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Active Antenna
Passive Antenna
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Reference Design for Detection Circuit
Active Antenna
R301
J302
Passive Antenna
RF_IN
C304
R303 22R
VCC_RF
C305
NM
NM
C302
J301
0R
R304
330R
C306
V_ANT
2.2uF
RF_IN
Q301
56pF
C301
C303
NM
NM
The most simplified power supply circuit is as follows:
C
VCC_RF
R302 10R
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2SA1037AKT146
2SA1037AKT146
R306 10K
R305 10K
Q302
C
R307 1K
AADET_N
V_ANT
3
1. Fig.1 shows the passive antenna circuit, here, Pi circuit (C301,C302,C303) is reserved for impedance matching for antenna.
Reference Design for ANTON Circuit
By default, C301 and C303 are not mounted, C302 is 56pF.
2. Fig.2 shows the basic active antenna circuit, here, Pi circuit (C304,R301,C305) is reserved for impedance matching for antenna.
By default, C304 and C305 are not mounted, R301 is 0R. A 10R resistor (R302) is needed between VCC_RF and V_ANT to supply
Q303
R309
VCC_RF
10R
B
R308
10K
SI2333
V_ANT
power. When use active antenne, the R301 must not be capacitance, because the current flows through R301 to the antenna.
3. Fig.3 shows the reference design for detection circuit.When active antenna is removed or not connected well, AADET_N will keep
B
a high level to indicate the active antenna absent. AADET_N will change to a low level when active antenna is connected well.
4. Fig.4 shows the active antenna with ANTON circuit. The voltage level of ANTON will be pulled down in sleep mode.
ANTON
Q304
5. The typical value of VCC_RF is 3.3V, ranging from 2.8V to 4.3V. If it is not suitable for the active antenna, it can be replaced
by an external LDO.
DTC143ZEBTL
6. Impedance of RF trace should be controlled by 50 ohm and the length should be kept as short as possible.
For more details, please refer to L26 Hardware Design.
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Quectel Wireless Solutions
A
DRAWN BY
<Rain Zhou>
CHECKED BY
<David WEI>
6
5
4
3
2
TITLE
<L26_Reference_Design>
PORJECT
<L26>
SIZE
SHEET
A2
3 of 3
VER
<V1.01>
<2013.05>
1
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