Quectel EG21-G Supplement

EG21-G
Hardware Design
LTE Module Series
Rev. EG21-G_Hardware_Design_V1.0
Date: 2019-03-12
Status: Released
www.quectel.com

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About the Document
History
Revision
Date
Author
Description
1.0
2019-03-11
Lorry XU/
Harry HUANG
Initial

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Contents
About the Document................................................................................................................................ 2
Contents.................................................................................................................................................... 3
Table Index ............................................................................................................................................... 5
Figure Index.............................................................................................................................................. 7
1Introduction....................................................................................................................................... 9
1.1. Safety Information................................................................................................................. 10
2Product Concept ............................................................................................................................. 11
2.1. General Description ...............................................................................................................11
2.2. Key Features.........................................................................................................................12
2.3. Functional Diagram............................................................................................................... 14
2.4. Evaluation Board................................................................................................................... 15
3Application Interfaces..................................................................................................................... 16
3.1. General Description .............................................................................................................. 16
3.2. Pin Assignment ..................................................................................................................... 17
3.3. Pin Description......................................................................................................................18
3.4. Operating Modes ..................................................................................................................26
3.5. Power Saving........................................................................................................................27
3.5.1. Sleep Mode..................................................................................................................27
3.5.1.1. UART Application...............................................................................................27
3.5.1.2. USB Application with USB Remote Wakeup Function ....................................... 28
3.5.1.3. USB Application with USB Suspension/Resume and RI Function .....................29
3.5.1.4. USB Application without USB Suspension Function ..........................................30
3.5.2. Airplane Mode.............................................................................................................. 30
3.6. Power Supply........................................................................................................................31
3.6.1. Power Supply Pins.......................................................................................................31
3.6.2. Decrease Voltage Drop................................................................................................ 32
3.6.3. Reference Design for Power Supply............................................................................33
3.6.4. Monitor the Power Supply............................................................................................ 33
3.7. Power-on and off Scenarios..................................................................................................34
3.7.1. Turn on Module Using the PWRKEY ........................................................................... 34
3.7.2. Turn off Module............................................................................................................ 35
3.7.2.1. Turn off Module Using the PWRKEY Pin ........................................................... 36
3.7.2.2. Turn off Module Using AT Command .................................................................36
3.8. Reset the Module..................................................................................................................36
3.9. (U)SIM Interface.................................................................................................................... 38
3.10. USB Interface........................................................................................................................40
3.11. UART Interfaces.................................................................................................................... 42
3.12. PCM and I2C Interfaces........................................................................................................ 44
3.13. SD Card Interface ................................................................................................................. 46
3.14. ADC Interfaces...................................................................................................................... 48
3.15. Network Status Indication .....................................................................................................49
3.16. STATUS ................................................................................................................................ 50

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3.17. Behaviors of RI .....................................................................................................................51
3.18. USB_BOOT Interface............................................................................................................51
4GNSS Receiver................................................................................................................................ 54
4.1. General Description .............................................................................................................. 54
4.2. GNSS Performance .............................................................................................................. 54
4.3. Layout Guidelines ................................................................................................................. 55
5Antenna Interfaces.......................................................................................................................... 56
5.1. Main/Rx-diversity Antenna Interfaces.................................................................................... 56
5.1.1. Pin Definition................................................................................................................ 56
5.1.2. Operating Frequency ...................................................................................................56
5.1.3. Reference Design of RF Antenna Interface ................................................................. 58
5.1.4. Reference Design of RF Layout................................................................................... 58
5.2. GNSS Antenna Interface....................................................................................................... 60
5.3. Antenna Installation ..............................................................................................................61
5.3.1. Antenna Requirement..................................................................................................61
5.3.2. Recommended RF Connector for Antenna Installation................................................62
6Electrical, Reliability and Radio Characteristics .......................................................................... 65
6.1. Absolute Maximum Ratings .................................................................................................. 65
6.2. Power Supply Ratings........................................................................................................... 66
6.3. Operation and Storage Temperatures ...................................................................................66
6.4. Current Consumption............................................................................................................ 67
6.5. RF Output Power .................................................................................................................. 72
6.6. RF Receiving Sensitivity .......................................................................................................72
6.7. Electrostatic Discharge .........................................................................................................74
6.8. Thermal Consideration.......................................................................................................... 74
7Mechanical Dimensions.................................................................................................................. 77
7.1. Mechanical Dimensions of the Module..................................................................................77
7.2. Recommended Footprint....................................................................................................... 79
7.3. Design Effect Drawings of the Module ..................................................................................80
8Storage, Manufacturing and Packaging........................................................................................ 81
8.1. Storage .................................................................................................................................81
8.2. Manufacturing and Soldering ................................................................................................82
8.3. Packaging .............................................................................................................................83
9Appendix A References.................................................................................................................. 85
10 Appendix B GPRS Coding Schemes............................................................................................. 89
11 Appendix C GPRS Multi-slot Classes............................................................................................ 90
12 Appendix D EDGE Modulation and Coding Schemes.................................................................. 92

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Table Index
TABLE 1: FREQUENCY BANDS OF EG21-G MODULE...................................................................................11
TABLE 2: KEY FEATURES OF EG21-G MODULE........................................................................................... 12
TABLE 3: I/O PARAMETERS DEFINITION....................................................................................................... 18
TABLE 4: PIN DESCRIPTION........................................................................................................................... 18
TABLE 5: OVERVIEW OF OPERATING MODES............................................................................................. 27
TABLE 6: VBAT AND GND PINS....................................................................................................................... 31
TABLE 7: PIN DEFINITION OF PWRKEY ........................................................................................................ 34
TABLE 8: RESET_N PIN DESCRIPTION ......................................................................................................... 37
TABLE 9: PIN DEFINITION OF (U)SIM INTERFACE ....................................................................................... 38
TABLE 10: PIN DESCRIPTION OF USB INTERFACE ..................................................................................... 40
TABLE 11: PIN DEFINITION OF MAIN UART INTERFACE ............................................................................. 42
TABLE 12: PIN DEFINITION OF DEBUG UART INTERFACE ......................................................................... 42
TABLE 13: LOGIC LEVELS OF DIGITAL I/O .................................................................................................... 43
TABLE 14: PIN DEFINITION OF PCM AND I2C INTERFACES ....................................................................... 45
TABLE 15: PIN DEFINITION OF SD CARD INTERFACE ................................................................................ 47
TABLE 18: PIN DEFINITION OF ADC INTERFACES....................................................................................... 48
TABLE 19: CHARACTERISTIC OF ADC .......................................................................................................... 49
TABLE 20: PIN DEFINITION OF NETWORK CONNECTION STATUS/ACTIVITY INDICATOR...................... 49
TABLE 21: WORKING STATE OF THE NETWORK CONNECTION STATUS/ACTIVITY INDICATOR ........... 49
TABLE 22: PIN DEFINITION OF STATUS ........................................................................................................ 50
TABLE 23: BEHAVIORS OF RI ......................................................................................................................... 51
TABLE 24: PIN DEFINITION OF USB_BOOT INTERFACE ............................................................................. 52
TABLE 25: GNSS PERFORMANCE ................................................................................................................. 54
TABLE 26: PIN DEFINITION OF THE RF ANTENNA....................................................................................... 56
TABLE 27: MODULE OPERATING FREQUENCIES........................................................................................ 56
TABLE 28: PIN DEFINITION OF GNSS ANTENNA INTERFACE..................................................................... 60
TABLE 29: GNSS FREQUENCY....................................................................................................................... 61
TABLE 30: ANTENNA REQUIREMENTS.......................................................................................................... 62
TABLE 31: ABSOLUTE MAXIMUM RATINGS .................................................................................................. 65
TABLE 32: THE MODULE POWER SUPPLY RATINGS .................................................................................. 66
TABLE 33: OPERATION AND STORAGE TEMPERATURES .......................................................................... 66
TABLE 34: EG21-G CURRENT CONSUMPTION............................................................................................. 67
TABLE 35: GNSS CURRENT CONSUMPTION OF EG21-G MODULE........................................................... 71
TABLE 36: RF OUTPUT POWER ..................................................................................................................... 72
TABLE 37: EG21-G CONDUCTED RF RECEIVING SENSITIVITY ................................................................. 72
TABLE 38: ELECTROSTATICS DISCHARGE CHARACTERISTICS (25ºC, 45% RELATIVE HUMIDITY)...... 74
TABLE 39: RECOMMENDED THERMAL PROFILE PARAMETERS ............................................................... 82
TABLE 40: RELATED DOCUMENTS................................................................................................................ 85
TABLE 41: TERMS AND ABBREVIATIONS ...................................................................................................... 85
TABLE 42: DESCRIPTION OF DIFFERENT CODING SCHEMES .................................................................. 89
TABLE 43: GPRS MULTI-SLOT CLASSES ...................................................................................................... 90

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TABLE 44: EDGE MODULATION AND CODING SCHEMES........................................................................... 92

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Figure Index
FIGURE 1: FUNCTIONAL DIAGRAM ............................................................................................................... 15
FIGURE 2: PIN ASSIGNMENT (TOP VIEW) .................................................................................................... 17
FIGURE 3: SLEEP MODE APPLICATION VIA UART....................................................................................... 28
FIGURE 4: SLEEP MODE APPLICATION WITH USB REMOTE WAKEUP .................................................... 29
FIGURE 5: SLEEP MODE APPLICATION WITH RI ......................................................................................... 30
FIGURE 6: SLEEP MODE APPLICATION WITHOUT SUSPENSION FUNCTION.......................................... 30
FIGURE 7: POWER SUPPLY LIMITS DURING BURST TRANSMISSION...................................................... 32
FIGURE 8: STAR STRUCTURE OF THE POWER SUPPLY............................................................................ 33
FIGURE 9: REFERENCE CIRCUIT OF POWER SUPPLY .............................................................................. 33
FIGURE 10: TURN ON THE MODULE BY USING DRIVING CIRCUIT ........................................................... 34
FIGURE 11: TURN ON THE MODULE BY USING KEYSTROKE.................................................................... 35
FIGURE 12: POWER-ON SCENARIO OF MODULE ....................................................................................... 35
FIGURE 13: POWER-OFF SCENARIO OF MODULE...................................................................................... 36
FIGURE 14: REFERENCE CIRCUIT OF RESET_N BY USING DRIVING CIRCUIT ...................................... 37
FIGURE 15: REFERENCE CIRCUIT OF RESET_N BY USING BUTTON ...................................................... 37
FIGURE 16: TIMING OF RESETTING MODULE ............................................................................................. 38
FIGURE 17: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH AN 8-PIN (U)SIM CARD CONNECTOR
................................................................................................................................................................... 39
FIGURE 18: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH A 6-PIN (U)SIM CARD CONNECTOR. 39
FIGURE 19: REFERENCE CIRCUIT OF USB APPLICATION ......................................................................... 41
FIGURE 20: REFERENCE CIRCUIT WITH TRANSLATOR CHIP ................................................................... 43
FIGURE 21: REFERENCE CIRCUIT WITH TRANSISTOR CIRCUIT .............................................................. 44
FIGURE 22: PRIMARY MODE TIMING ............................................................................................................ 45
FIGURE 23: AUXILIARY MODE TIMING .......................................................................................................... 45
FIGURE 24: REFERENCE CIRCUIT OF PCM APPLICATION WITH AUDIO CODEC .................................... 46
FIGURE 25: REFERENCE CIRCUIT OF SD CARD......................................................................................... 47
FIGURE 29: REFERENCE CIRCUIT OF THE NETWORK INDICATOR.......................................................... 50
FIGURE 30: REFERENCE CIRCUITS OF STATUS ......................................................................................... 51
FIGURE 31: REFERENCE CIRCUIT OF USB_BOOT INTERFACE ................................................................ 52
FIGURE 32: TIMING SEQUENCE FOR ENTERING INTO EMERGENCY DOWNLOAD MODE.................... 53
FIGURE 32: REFERENCE CIRCUIT OF RF ANTENNA INTERFACE ............................................................. 58
FIGURE 33: MICROSTRIP DESIGN ON A 2-LAYER PCB............................................................................... 59
FIGURE 34: COPLANAR WAVEGUIDE DESIGN ON A 2-LAYER PCB........................................................... 59
FIGURE 35: COPLANAR WAVEGUIDE DESIGN ON A 4-LAYER PCB (LAYER 3 AS REFERENCE GROUND)
................................................................................................................................................................... 59
FIGURE 36: COPLANAR WAVEGUIDE DESIGN ON A 4-LAYER PCB (LAYER 4 AS REFERENCE GROUND)
................................................................................................................................................................... 60
FIGURE 37: REFERENCE CIRCUIT OF GNSS ANTENNA............................................................................. 61
FIGURE 38: DIMENSIONS OF THE U.FL-R-SMT CONNECTOR (UNIT: MM)................................................ 63
FIGURE 39: MECHANICALS OF U.FL-LP CONNECTORS............................................................................. 63
FIGURE 40: SPACE FACTOR OF MATED CONNECTOR (UNIT: MM) ........................................................... 64

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FIGURE 41: REFERENCED HEATSINK DESIGN (HEATSINK AT THE TOP OF THE MODULE) .................. 75
FIGURE 42: REFERENCED HEATSINK DESIGN (HEATSINK AT THE BACKSIDE OF CUSTOMERS’ PCB)
................................................................................................................................................................... 75
FIGURE 43: MODULE TOP AND SIDE DIMENSIONS..................................................................................... 77
FIGURE 44: MODULE BOTTOM DIMENSIONS (BOTTOM VIEW) ................................................................. 78
FIGURE 45: RECOMMENDED FOOTPRINT (TOP VIEW) .............................................................................. 79
FIGURE 46: TOP VIEW OF THE MODULE...................................................................................................... 80
FIGURE 47: BOTTOM VIEW OF THE MODULE.............................................................................................. 80
FIGURE 48: REFLOW SOLDERING THERMAL PROFILE.............................................................................. 82
FIGURE 49: TAPE AND REEL SPECIFICATIONS ........................................................................................... 84
FIGURE 51: TAPE AND REEL DIRECTIONS ................................................................................................... 84

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1Introduction
This document defines EG21-G module, and describes its air interfaces and hardware interfaces which
are connected with customers’ applications.
This document can help customers quickly understand module interface specifications, electrical and
mechanical details as well as other related information of EG21-G module. To facilitate its application in
different fields, relevant reference design is also provided for customers’ reference. Associated with
application note and user guide, customers can use the module to design and set up mobile applications
easily.

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1.1. Safety Information
The following safety precautions must be observed during all phases of operation, such as usage, service
or repair of any cellular terminal or mobile incorporating EG21-G module. Manufacturers of the cellular
terminal should send the following safety information to users and operating personnel, and incorporate
these guidelines into all manuals supplied with the product. If not so, Quectel assumes no liability for
customers’ failure to comply with these precautions.
Full attention must be given to driving at all times in order to reduce the risk of an
accident. Using a mobile while driving (even with a handsfree kit) causes
distraction and can lead to an accident. Please comply with laws and regulations
restricting the use of wireless devices while driving.
Switch off the cellular terminal or mobile before boarding an aircraft. The operation
of wireless appliances in an aircraft is forbidden to prevent interference with
communication systems. If the device offers an Airplane Mode, then it should be
enabled prior to boarding an aircraft. Please consult the airline staff for more
restrictions on the use of wireless devices on boarding the aircraft.
Wireless devices may cause interference on sensitive medical equipment, so
please be aware of the restrictions on the use of wireless devices when in
hospitals, clinics or other healthcare facilities.
Cellular terminals or mobiles operating over radio signals and cellular network
cannot be guaranteed to connect in all possible conditions (for example, with
unpaid bills or with an invalid (U)SIM card). When emergent help is needed in such
conditions, please remember using emergency call. In order to make or receive a
call, the cellular terminal or mobile must be switched on in a service area with
adequate cellular signal strength.
The cellular terminal or mobile contains a transmitter and receiver. When it is ON, it
receives and transmits radio frequency signals. RF interference can occur if it is
used close to TV set, radio, computer or other electric equipment.
In locations with potentially explosive atmospheres, obey all posted signs to turn
off wireless devices such as your phone or other cellular terminals. Areas with
potentially explosive atmospheres include fuelling areas, below decks on boats,
fuel or chemical transfer or storage facilities, areas where the air contains
chemicals or particles such as grain, dust or metal powders, etc.

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2Product Concept
2.1. General Description
EG21-G is an LTE-FDD/LTE-TDD/UMTS/GSM wireless communication module with receive diversity. It
provides data connectivity on LTE-FDD, LTE-TDD, DC-HSDPA, HSPA+, HSDPA, HSUPA, UMTS, EDGE
and GPRS networks. It also provides GNSS 1) and voice functionality 2) for customers’ specific
applications. The following table shows the frequency bands of EG21-G module.
Table 1: Frequency Bands of EG21-G Module
1. 1) GNSS function is optional.
2. 2) EG21-G module includes Data-only and Telematics versions. Data-only version does not support
voice function, while Telematics version supports it.
With a compact profile of 29.0mm × 32.0mm × 2.4mm, EG21-G can meet almost all requirements for
M2M applications such as automotive, metering, tracking system, security, router, wireless POS, mobile
computing device, PDA phone, tablet PC, etc.
EG21-G is an SMD type module which can be embedded into applications through its 144-pin LAG pads.
Network Mode/GNSS
EG21-G
LTE-FDD
(with receive diversity)
B1/B2/B3/B4/B5/B7/B8/B12/B13/B18/B19/B20/B25/B26/B28
LTE-TDD
(with receive diversity)
B38/B39/B40/B41
UMTS
(with receive diversity)
B1/B2/B4/B5/B6/B8/B19
GSM
850/900/1800/1900MHz
GNSS 1) Function
GPS, GLONASS, BeiDou/Compass, Galileo, QZSS
NOTES

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2.2. Key Features
The following table describes the detailed features of EG21-G module.
Table 2: Key Features of EG21-G Module
Feature
Details
Power Supply
Supply voltage: 3.3V~4.3V
Typical supply voltage: 3.8V
Transmitting Power
Class 4 (33dBm±2dB) for GSM850
Class 4 (33dBm±2dB) for EGSM900
Class 1 (30dBm±2dB) for DCS1800
Class 1 (30dBm±2dB) for PCS1900
Class E2 (27dBm±3dB) for GSM850 8-PSK
Class E2 (27dBm±3dB) for EGSM900 8-PSK
Class E2 (26dBm±3dB) for DCS1800 8-PSK
Class E2 (26dBm±3dB) for PCS1900 8-PSK
Class 3 (24dBm+1/-3dB) for WCDMA bands
Class 3 (23dBm±2dB) for LTE FDD bands
Class 3 (23dBm±2dB) for LTE TDD bands
LTE Features
Support up to non-CA Cat 1 FDD and TDD
Support 1.4MHz~20MHz RF bandwidth
Support MIMO in DL direction
LTE-FDD: Max 10Mbps (DL), Max 5Mbps (UL)
LTE-TDD: Max 8.96Mbps (DL), Max 3.1Mbps (UL)
UMTS Features
Support 3GPP R8 DC-HSDPA, HSPA+, HSDPA, HSUPA and WCDMA
Support QPSK, 16-QAM and 64-QAM modulation
DC-HSDPA: Max 7.2Mbps (DL)
HSUPA: Max 5.76Mbps (UL)
WCDMA: Max 384Kbps (DL), Max 384Kbps (UL)
GSM Features
GPRS:
Support GPRS multi-slot class 33 (33 by default)
Coding scheme: CS-1, CS-2, CS-3 and CS-4
Max 107Kbps (DL), Max 85.6Kbps (UL)
EDGE:
Support EDGE multi-slot class 33 (33 by default)
Support GMSK and 8-PSK for different MCS (Modulation and Coding
Scheme)
Downlink coding schemes: CS 1-4 and MCS 1-9
Uplink coding schemes: CS 1-4 and MCS 1-9
Max 296Kbps (DL), Max 236.8Kbps (UL)

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Internet Protocol
Features
Support TCP/UDP/PPP/FTP/HTTP/NTP/PING/QMI/NITZ/CMUX*/HTTPS*/
SMTP/MMS*/FTPS*/SMTPS*/SSL*/FILE* protocols
Support PAP (Password Authentication Protocol) and CHAP (Challenge
Handshake Authentication Protocol) protocols which are usually used for
PPP connections
SMS
Text and PDU mode
Point to point MO and MT
SMS cell broadcast
SMS storage: ME by default
(U)SIM Interface
Support USIM/SIM card: 1.8V, 3.0V
Audio Features
Support one digital audio interface: PCM interface
GSM: HR/FR/EFR/AMR/AMR-WB
WCDMA: AMR/AMR-WB
LTE: AMR/AMR-WB
Support echo cancellation and noise suppression
PCM Interface
Used for audio function with external codec
Support 16-bit linear data format
Support long frame synchronization and short frame synchronization
Support master and slave modes, but must be the master in long frame
synchronization
USB Interface
Compliant with USB 2.0 specification (slave only); the data transfer rate can
reach up to 480Mbps
Used for AT command communication, data transmission, GNSS NMEA
output, software debugging, firmware upgrade and voice over USB*
Support USB serial drivers for: Windows 7/8/8.1/10, Windows CE
5.0/6.0/7.0*, Linux 2.6/3.x/4.1~4.14, Android 4.x/5.x/6.x/7.x/8.x, etc.
UART Interfaces
Main UART:
Used for AT command communication and data transmission
Baud rates reach up to 921600bps, 115200bps by default
Support RTS and CTS hardware flow control
Debug UART:
Used for Linux console and log output
115200bps baud rate
SD Card Interface
Support SD 3.0 protocol
Rx-diversity
Support LTE/WCDMA Rx-diversity
GNSS Features
Gen8C Lite of Qualcomm
Protocol: NMEA 0183
AT Commands
Compliant with 3GPP TS 27.007, 27.005 and Quectel enhanced AT
commands
Network Indication
Two pins including NET_MODE and NET_STATUS to indicate network
connectivity status

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Antenna Interfaces
Including main antenna interface (ANT_MAIN), Rx-diversity antenna
interface (ANT_DIV) and GNSS antenna interface (ANT_GNSS)
Physical Characteristics
Size: (29.0±0.15)mm × (32.0±0.15)mm × (2.4±0.2)mm
Weight: approx. 4.9g
Temperature Range
Operation temperature range: -35°C ~ +75°C 1)
Extended temperature range: -40°C ~ +85°C 2)
Storage temperature range: -40°C ~ +90°C
Firmware Upgrade
USB interface or DFOTA*
RoHS
All hardware components are fully compliant with EU RoHS directive.
1. 1) Within operation temperature range, the module is 3GPP compliant.
2. 2) Within extended temperature range, the module remains the ability to establish and maintain a
voice, SMS, data transmission, emergency call, etc. There is no unrecoverable malfunction. There
are also no effects on radio spectrum and no harm to radio network. Only one or more parameters like
Pout might reduce in their value and exceed the specified tolerances. When the temperature returns to
normal operation temperature levels, the module will meet 3GPP specifications again.
3. “*” means under development.
2.3. Functional Diagram
The following figure shows a block diagram of EG21-G and illustrates the major functional parts.
Power management
Baseband
DDR+NAND flash
Radio frequency
Peripheral interfaces
NOTES

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Baseband
PMIC
Transceiver NAND
DDR2
SDRAM
PA
PAM
LNA
Switch
ANT_MAIN ANT_DIVANT_GNSS
VBAT_BB
VBAT_RF
APT
PWRKEY
ADCs
VDD_EXT USB (U)SIM PCM UARTsI2C
RESET_N
19.2M
XO
STATUS
GPIOs
SAW
Control
IQ Control
Duplex
SAW
Tx
PRx DRx
SD
Figure 1: Functional Diagram
“*” means under development.
2.4. Evaluation Board
In order to help customers develop applications with EG21-G, Quectel supplies an evaluation board
(EVB), USB to RS-232 converter cable, earphone, antenna and other peripherals to control or test the
module.
NOTE

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3Application Interfaces
3.1. General Description
EG21-G is equipped with 144 LGA pads that can be connected to cellular application platform.
Sub-interfaces included in these pads are described in detail in the following chapters:
Power supply
(U)SIM interface
USB interface
UART interfaces
PCM and I2C interfaces
SD card interface
ADC interfaces
Status indication
USB_BOOT interface

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3.2. Pin Assignment
The following figure shows the pin assignment of EG21-G module.
34
3
35 36 20 21 22 23 24 25 26 27 28 29 30 31 32 33
1
4
5
6
7
2
WAKEUP_IN1)
AP_READY
RESERVED
W_DISABLE#
NET_MODE1)
NET_STATUS
VDD_EXT
GND
GND
DBG_RXD
DBG_TXD
USIM_PRESENCE
USIM_VDD
USIM_DATA
USIM_CLK
USIM_RST
RESERVED
8
9
10
11
12
13
14
15
16
17
18
19
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55
USIM_GND
GND
RESET_N
PWRKEY2)
GND
SD_INS_DET
SDC2_DATA3 SDC2_DATA2 SDC2_DATA1 SDC2_DATA0
SDC2_CLK SDC2_CMD
ANT_DIV
GND
GND
USB_VBUS
USB_DM
USB_DP
RXD
TXD
DTR
RTS
CTS
DCD
RI
STATUS
VBAT_BB VBAT_BB
VBAT_RF
VBAT_RF
GND
RESERVED
GND
GND
ANT_MAIN
GND
ANT_GNSS
GND
ADC1
RESERVED
I2C_SDA
I2C_SCL
ADC0
GND
GND
GND
73
74
75
76
77
78
79
80
81
82
83
84
100
101
102
106
107
111
112
103
104
109
105
110
89
94
98
88
93
97
86
91
96
85
90
95
99
87
92
108
113
RESERVED
RESERVED
117
126
125
124
123
122
121
118
127
128
115 USB_BOOT1)
RESERVED
116
140
1371)
1361)
135
134
133
132
131
130
129
114
VDD_SDIO
Power Pins Signal Pins
GND Pins
RESERVED
RESERVED
14 1
14 2
RESERVED
RESERVED
14 3
14 4
119
120
RESERVED Pins
Bluetooth Pins
PCM_IN3) PCM_OUT3) PCM_SYNC3) PCM_CLK3)
BT_CTS1)*
BT_RXD*
BT_TXD*
BT_RTS*
139*
1381)
Figure 2: Pin Assignment (Top View)
1. 1) means that these pins cannot be pulled up before startup.
2. 2) PWRKEY output voltage is 0.8V because of the diode drop in the Qualcomm chipset.
3. 3) means these interface functions are only supported on Telematics version.
4. Keep all RESERVED pins and unused pins unconnected.
5. Pads 37~40 and 139 are used for Bluetooth (BT) function pins. BT function is under development.
6. GND pads 85~112 should be connected to ground in the design. RESERVED pads 73~84 should not
be designed in schematic and PCB decal, and these pins should be served as a keepout area.
7. “*” means under development.
NOTES

LTE Module Series
EG21-G Hardware Design
EG21-G_Hardware_Design 18 / 100
3.3. Pin Description
The following tables show the pin definition of EG21-G modules.
Table 3: I/O Parameters Definition
Type
Description
AI
Analog input
AO
Analog output
DI
Digital input
DO
Digital output
IO
Bidirectional
OD
Open drain
PI
Power input
PO
Power output
Table 4: Pin Description
Power Supply
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
VBAT_BB
59, 60
PI
Power supply for
module’s baseband
part
Vmax=4.3V
Vmin=3.3V
Vnorm=3.8V
It must be able to
provide sufficient
current up to 0.8A.
VBAT_RF
57, 58
PI
Power supply for
module’s RF part
Vmax=4.3V
Vmin=3.3V
Vnorm=3.8V
It must be able to
provide sufficient
current up to 1.8A in a
burst transmission.
VDD_EXT
7
PO
Provide 1.8V for
external circuit
Vnorm=1.8V
IOmax=50mA
Power supply for
external GPIO’s pull up
circuits.
If unused, keep it open.
GND
8, 9, 19,
22, 36, 46,
48, 50~54,
Ground

LTE Module Series
EG21-G Hardware Design
EG21-G_Hardware_Design 19 / 100
56, 72,
85~112
Turn on/off
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
PWRKEY
21
DI
Turn on/off the
module
VIHmax=2.1V
VIHmin=1.3V
VILmax=0.5V
The output voltage is
0.8V because of the
diode drop in the
Qualcomm chipset.
RESET_N
20
DI
Reset the module
VIHmax=2.1V
VIHmin=1.3V
VILmax=0.5V
If unused, keep it
open.
Status Indication
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
STATUS
61
OD
Indicate the module
operating status
The drive current
should be less than
0.9mA.
An external pull-up
resistor is required. If
unused, keep it open.
NET_MODE
5
DO
Indicate the module
network registration
mode
VOHmin=1.35V
VOLmax=0.45V
1.8V power domain.
Cannot be pulled up
before startup.
If unused, keep it
open.
NET_
STATUS
6
DO
Indicate the module
network activity
status
VOHmin=1.35V
VOLmax=0.45V
1.8V power domain.
If unused, keep it
open.
USB Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
USB_VBUS
71
PI
USB power supply,
used for USB
detection
Vmax=5.25V
Vmin=3.0V
Vnorm=5.0V
Typical: 5.0V
If unused, keep it
open.
USB_DP
69
IO
USB differential data
bus (+)
Compliant with USB
2.0 standard
specification.
Require differential
impedance of 90Ω.
If unused, keep it
open.
USB_DM
70
IO
USB differential data
bus (-)
Compliant with USB
2.0 standard
specification.
Require differential
impedance of 90Ω.
If unused, keep it
open.
(U)SIM Interface