Quectel BG95 - Page 33

LPWA Module Series
BG95&BG96 Compatible Design
BG95&BG96_Compatible_Design 32 / 47
VCCA VCCB
OE
A1
A2
A3
A4
A5
A6
A7
A8
GND
B1
B2
B3
B4
B5
B6
B7
B8
VDD_EXT
MAIN_RI
MAIN_DCD
MAIN_RTS
MAIN_RXD
MAIN_DTR
MAIN_CTS
MAIN_TXD
51K
51K
0.1uF
0.1uF
RI_MCU
DCD_MCU
RTS_MCU
RXD_MCU
DTR_MCU
CTS_MCU
TXD_MCU
VDD_MCU
Translator
10K
120K
RI
BG95 BG96
DCD
CTS
MAIN_RTS
RTS
MAIN_DTRMAIN_DTRMAIN_DTR
TXD
DTR
RXD
Figure 15: Reference Circuit with Translator Chip
Another example with transistor translation circuit is shown as below. For the design of circuits in dotted
lines, please refer to that of circuits in solid lines, but please pay attention to the direction of connection.
MCU/ARM
TXD
RXD
VDD_EXT
10K
VCC_MCU
4.7K
10K
VDD_EXT
MAIN_TXD
MAIN_RXD
MAIN_RTS
MAIN_CTS
MAIN_DTR
MAIN_RI
RTS
CTS
GND
GPIO MAIN_DCD
Module
GPIO
EINT
VDD_EXT
4.7K
GND
1nF
1nF
TXD
RXD
RTS
CTS
DTR
RI
GND
DCD
BG95 BG96
Figure 16: Reference Circuit with Transistor Circuit

Transistor circuit solution is not suitable for applications with high baud rates exceeding 460Kbps.
NOTE