LTE Standard Module Series
is recommended. The following figure shows a reference design.
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
0.1
μ
F
0.1
μ
F
RI_MCU
DCD_MCU
RTS_MCU
TXD_MCU
DTR_MCU
CTS_MCU
RXD_MCU
VDD_MCU
Translator
10
K
120K
Figure 23: Reference Circuit with Translator Chip
Please visit http://www.ti.com for more information.
Another example with transistor circuit is shown as below. For the design of circuits shown in dotted
lines, please refer to that shown in solid lines, but 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
1 nF
1 nF
Figure 24: Reference Circuit with Transistor Circuit
1. Transistor circuit solution is not suitable for applications with baud rates exceeding 460 kbps.
2. Please note that the module CTS is connected to the host CTS, and the module RTS is connected
NOTE