Service Guide
Table Of Contents
- Safety Information
- About the Document
- Contents
- Table Index
- Figure Index
- 1 Introduction
- 2 Product Overview
- 3 Operating Characteristics
- 4 Application Interfaces
- 5 Antenna Interfaces
- 6 Reliability, Radio, and Electrical Characteristics
- 7 Mechanical Information
- 8 Storage, Manufacturing, and Packaging
- 9 Appendix References
LTE Standard Module Series
EG915U_Series_Hardware_Design 50 / 90
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 μF
0.1 μF
RI_MCU
DCD_MCU
RTS_MCU
TXD_MCU
DTR_MCU
CTS_MCU
RXD_MCU
VDD_MCU
Translator
10K
120K
Connect to the CTS of MCU
Connect to the RTS of MCU
Connect to the RXD of MCU
Connect to the TXD of MCU
Figure 24: Reference Circuit with Translator Chip
Please visit http://www.ti.com for more information.
Another example with transistor circuit is shown as follows. For the design of circuits in dotted lines,
please refer to that of the 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
1 nF
1 nF
Figure 25: 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
to the host RTS.
3. When using pins 30, 38, and 39, please note that these pins will have a period of variable level
state (not controllable by software) after the module is powered on: first high level (3 V) for 2 s and
NOTE