Specifications

Smart Machine Smart Decision
SIM7600G_SIM7600G-H_Hardware Design _V1.01 28 2019-10-21
Figure 13: UART full modem
Figure 14: UART null modem
The MODULE UART is 1.8V voltage interface. If user’s UART application circuit is 3.3V voltage
interface, the level shifter circuits should be used for voltage matching. The TXB0108RGYR
provided by Texas Instruments is recommended. The following figure shows the voltage matching
reference design.
TXD
RXD
RTS
CTS
DTR
DCD
RI
A7
A1
A2
A3
A4
A5
A6
MODULE
TXB0108RGYR
UART port
A8
B7
B1
B2
B3
B4
B5
B6
B8
VCCA
OE
VDD_1V8 or
External 1V8
100nF
3.3V
100nF
VCCB
GND
TXD_3.3V
RXD_3.3V
RTS_3.3V
CTS_3.3V
DTR_3.3V
DCD_3.3V
RI_3.3V
47K 47K
Figure 15: Reference circuit of level shift
User can use another level shifter circuits as follow