Product Info

LTE Standard Module Series
EG91 Series Hardware Design
EG91_Series_Hardware_Design
48 / 102
10K
V
OL
0
0.45
V
V
OH
1.35
1.8
V
The module provides 1.8V UART interfaces. A level translator should be used if customers’ application is
equipped with a 3.3V UART interface. A level translator TXS0108EPWR provided by Texas Instruments is
recommended. The following figure shows a reference design.
VDD_EXT
0.1uF
VCCA
VCCB
0.1uF
VDD_MCU
RI
DCD
CTS
RTS
DTR
TXD
RXD
120K
51K
OE
A1
A2
A3
Translator
A4
A5
A6
A7
A8
GND
B1
B2
B3
B4
B5
B6
B7
B8
51K
RI_MCU
DCD_MCU
CTS_MCU
RTS_MCU
DTR_MCU
TXD_MCU
RXD_MCU
Figure 20: Reference Circuit with Translator Chip
Please visit http://www.ti.com for more information.
Another example with transistor translation circuit is shown as below. The circuit design of dotted line
section can refer to the circuit design of solid line section, in terms of both module input and output circuit
design. Please pay attention to the direction of connection.