Quectel EC21 Mini PCIe Series Supplement

EC21 Mini PCIe
Hardware Design
LTE Standard Module Series
Rev. EC21_Mini_PCIe_Hardware_Design_V1.4
Date: 2019-11-26
Status: Released
www.quectel.com

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About the Document
Revision History
Revision
Date
Author
Description
1.0
2016-06-07
Yeoman CHEN/
Frank WANG
Initial
1.1
2017-01-24
Lyndon LIU/
Rex WANG
1. Deleted description of EC21-AUTL and EC21-CT
Mini PCIe in Table 1.
2. Updated key features of EC21 Mini PCIe in Table 2.
3. Added current consumption of EC21 Mini PCIe in
Chapter 4.7.
4. Updated mechanical dimensions of EC21 Mini PCIe
in Figure 15.
5. Updated conducted RF output power in Table 16.
6. Updated conducted RF receiving sensitivity of
EC21-Ain Table 18.
7. Added conducted RF receiving sensitivity of
EC21-KL in Table 21.
8. Added conducted RF receiving sensitivity of
EC21-J in Table 22.
1.2
2019-04-30
Woody WU/
Nathan LIU/
Frank WANG
1. Added new variants EC21-EU Mini PCIe/EC21-EC
Mini PCIe and related information.
2. Added pin definition and description of pin 44 in
Figure 2 and Table 4.
3. Updated mechanical dimensions in Figure 18.
4. Added USIM_PRESENCE in (U)SIM interface and
updated the reference circuit in Chapter 3.4.
5. Updated reference circuit of USB interface in
Chapter 3.5.
6. Modified description of W_DISABLE# signal in
Chapter 3.8.3.
7. Modified description of LED_WWAN# signal in
Chapter 3.8.5.

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8. Added thermal consideration in Chapter 6.7.
9. Updated UMTS and GSM features and added
storage temperature range in Table 2.
10. Added operating frequencies in Table 15
11. Added GNSS frequency in Table 16.
12. Updated antenna requirements in Table 17.
13. Updated EC21 Mini PCIe conducted RF output
power in Table 20.
14. Updated conducted RF receiving sensitivity of
EC21-E Mini PCIe in Table 21.
15. Updated conducted RF receiving sensitivity of
EC21-A Mini PCIe in Table 22.
16. Updated conducted RF receiving sensitivity of
EC21-V Mini PCIe in Table 23
17. Updated conducted RF receiving sensitivity of
EC21-AUT Mini PCIe in Table 24.
18. Added conducted RF receiving sensitivity of
EC21-AU Mini PCIe in Table 27.
19. Added conducted RF receiving sensitivity of
EC21-EU Mini PCIe in Table 28.
20. Added conducted RF receiving sensitivity of
EC21-EC Mini PCIe in Table 29.
21. Added current consumption of EC21-EC Mini PCIe
in Table 34.
1.3
2019-08-19
Ward WANG/
Owen WEI
1. Deleted the information of GNSS supported on
EC21-EC Mini PCIe in Table 1.
2. Added ThreadX variant EC21-AUX Mini PCIe and
updated related contents in Table 1.
3. Updated supported protocols and USB serial driver
in Table 2.
4. Updated conducted RF receiving sensitivity of
EC21-EU Mini PCIe in Table 29.
5. Added conducted RF receiving sensitivity of
EC21-AUX Mini PCIe in Table 31.
6. Added current consumption of EC21-AUX Mini
PCIe in Table 36.
7. Added current consumption of EC21-EU Mini PCIe
in Table 37.
8. Added current consumption of EC21-AU Mini PCIe
in Table 38.
9. Added note 2 for antenna requirement in Chapter
5.4.1.
10. Deleted current consumption of EC21-EC Mini
PCIe, and the data will be updated in the future

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version.
1.4
2019-11-26
Fanny CHEN
1. Removed related information of ThreadX OS
because the baseline has been updated.
2. Updated the supported protocols and USB serial
drivers in Table 2.
3. Added operating modes of module in Chapter 3.3.
4. Updated description of W_DISABLE# in Chapter
3.10.3.
5. Updated the notes for GNSS performance in
Chapter 4.2.
6. Added current consumption of EC21-J Mini PCIe in
Table 40.
7. Updated the Mini PCI Express connector in Chapter
7.3.

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Contents
About the Document...................................................................................................................................2
Contents.......................................................................................................................................................5
Table Index...................................................................................................................................................7
Figure Index.................................................................................................................................................9
1Introduction ........................................................................................................................................10
1.1. Safety Information....................................................................................................................11
2Product Concept................................................................................................................................12
2.1. General Description.................................................................................................................12
2.2. Description of Module Series ..................................................................................................13
2.3. Key Features ...........................................................................................................................14
2.4. Functional Diagram .................................................................................................................17
3Application Interfaces .......................................................................................................................18
3.1. Pin Assignment........................................................................................................................18
3.2. Pin Description.........................................................................................................................19
3.1. Operating Modes.....................................................................................................................22
3.2. Power Saving...........................................................................................................................23
3.2.1. Sleep Mode....................................................................................................................23
3.2.2. Airplane Mode................................................................................................................23
3.3. Power Supply...........................................................................................................................23
3.4. (U)SIM Interface ......................................................................................................................24
3.5. USB Interface ..........................................................................................................................26
3.6. UART Interface........................................................................................................................28
3.7. PCM and I2C Interfaces..........................................................................................................29
3.8. Control and Indication Signals.................................................................................................31
3.8.1. RI Signal.........................................................................................................................32
3.8.2. DTR Signal.....................................................................................................................32
3.8.3. W_DISABLE# Signal......................................................................................................32
3.8.4. PERST# Signal..............................................................................................................33
3.8.5. LED_WWAN# Signal .....................................................................................................33
3.8.6. WAKE# Signal................................................................................................................34
4GNSS Receiver...................................................................................................................................36
4.1. General Description.................................................................................................................36
4.2. GNSS Performance.................................................................................................................36
4.3. GNSS Frequency.....................................................................................................................37
5Antenna Connection..........................................................................................................................38
5.1. Antenna Connectors................................................................................................................38
5.1.1. Operating Frequency .....................................................................................................38
5.2. Antenna Requirements............................................................................................................39
5.3. Recommended Mating Plugs forAntenna Connection...........................................................40

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6Electrical, Reliability and Radio Characteristics............................................................................42
6.1. General Description.................................................................................................................42
6.2. Power Supply Requirements...................................................................................................42
6.3. I/O Requirements.....................................................................................................................43
6.4. RF Characteristics...................................................................................................................43
6.5. ESD Characteristics ................................................................................................................49
6.6. Current Consumption ..............................................................................................................49
6.7. Thermal Consideration............................................................................................................60
7Dimensions and Packaging..............................................................................................................62
7.1. General Description.................................................................................................................62
7.2. Mechanical Dimensions of EC21 Mini PCIe............................................................................62
7.3. Standard Dimensions of Mini PCI Express .............................................................................63
7.4. Packaging Specifications.........................................................................................................64
8Appendix A References.....................................................................................................................65

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Table Index
TABLE 1: DESCRIPTION OF EC21 MINI PCIE................................................................................................ 13
TABLE 2: KEY FEATURES OF EC21 MINI PCIE ............................................................................................. 14
TABLE 3: I/O PARAMETERS DEFINITION....................................................................................................... 19
TABLE 4: PIN DESCRIPTION........................................................................................................................... 19
TABLE 5: OVERVIEW OF OPERATING MODES............................................................................................. 22
TABLE 6: PIN DEFINITION OF VCC_3V3 AND GND PINS............................................................................. 23
TABLE 7: PIN DEFINITION OF (U)SIM INTERFACE ....................................................................................... 24
TABLE 8: PIN DEFINITION OF USB INTERFACE ........................................................................................... 26
TABLE 9: PIN DEFINITION OF MAIN UART INTERFACE............................................................................... 28
TABLE 10: PIN DEFINITION OF PCM AND I2C INTERFACES....................................................................... 29
TABLE 11: PIN DEFINITION OF CONTROLAND INDICATION SIGNALS...................................................... 31
TABLE 12: AIRPLANE MODE CONTROLLED BY HARDWARE METHOD..................................................... 32
TABLE 13: AIRPLANE MODE CONTROLLED BY SOFTWARE METHOD ..................................................... 33
TABLE 14: INDICATIONS OF NETWORK STATUS (AT+QCFG="LEDMODE",0, DEFAULT SETTING)......... 34
TABLE 15: INDICATIONS OF NETWORK STATUS (AT+QCFG="LEDMODE",2) ........................................... 34
TABLE 16: GNSS PERFORMANCE ................................................................................................................. 36
TABLE 17: GNSS FREQUENCY....................................................................................................................... 37
TABLE 18: OPERATING FREQUENCIES ........................................................................................................ 38
TABLE 19: ANTENNA REQUIREMENTS.......................................................................................................... 39
TABLE 20: POWER SUPPLY REQUIREMENTS.............................................................................................. 42
TABLE 21: I/O REQUIREMENTS...................................................................................................................... 43
TABLE 22: CONDUCTED RF OUTPUT POWER OF EC21 MINI PCIE........................................................... 43
TABLE 23: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-E MINI PCIE.......................................... 44
TABLE 24: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-A MINI PCIE.......................................... 44
TABLE 25: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-V MINI PCIE.......................................... 45
TABLE 26: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-AUT MINI PCIE..................................... 45
TABLE 27: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-KL MINI PCIE........................................ 45
TABLE 28: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-J MINI PCIE .......................................... 46
TABLE 29: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-AU MINI PCIE....................................... 46
TABLE 30: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-EU MINI PCIE....................................... 47
TABLE 31: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-EC MINI PCIE....................................... 47
TABLE 32: CONDUCTED RF RECEIVING SENSITIVITY OF EC21-AUX MINI PCIE..................................... 48
TABLE 33: ESD CHARACTERISTICS OF EC21 MINI PCIE............................................................................ 49
TABLE 34: CURRENT CONSUMPTION OF EC21-A MINI PCIE ..................................................................... 49
TABLE 35: CURRENT CONSUMPTION OF EC21-V MINI PCIE..................................................................... 50
TABLE 36: CURRENT CONSUMPTION OF EC21-KL MINI PCIE................................................................... 51
TABLE 37: CURRENT CONSUMPTION OF EC21-AUX MINI PCIE................................................................ 51
TABLE 38: CURRENT CONSUMPTION OF EC21-EU MINI PCIE .................................................................. 54
TABLE 39: CURRENT CONSUMPTION OF EC21-AU MINI PCIE .................................................................. 56
TABLE 40: CURRENT CONSUMPTION OF EC21-J MINI PCIE...................................................................... 59
TABLE 41: GNSS CURRENT CONSUMPTION OF EC21 MINI PCIE SERIES MODULE............................... 60

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TABLE 42: RELATED DOCUMENTS................................................................................................................ 65
TABLE 43: TERMS AND ABBREVIATIONS...................................................................................................... 65

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Figure Index
FIGURE 1: FUNCTIONAL DIAGRAM ............................................................................................................... 17
FIGURE 2: PIN ASSIGNMENT ......................................................................................................................... 18
FIGURE 3: REFERENCE CIRCUIT OF POWER SUPPLY .............................................................................. 24
FIGURE 4: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH AN 8-PIN (U)SIM CARD CONNECTOR 25
FIGURE 5: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH A 6-PIN (U)SIM CARD CONNECTOR... 25
FIGURE 6: REFERENCE CIRCUIT OF USB INTERFACE .............................................................................. 27
FIGURE 7: REFERENCE CIRCUIT OF POWER SUPPLY .............................................................................. 28
FIGURE 8: TIMING IN PRIMARY MODE.......................................................................................................... 30
FIGURE 9: TIMING IN AUXILIARY MODE........................................................................................................ 30
FIGURE 10: REFERENCE CIRCUIT OF PCM APPLICATION WITH AUDIO CODEC.................................... 31
FIGURE 11: RI BEHAVIORS............................................................................................................................. 32
FIGURE 12: TIMING OF RESETTING MODULE ............................................................................................. 33
FIGURE 13: LED_WWAN# SIGNAL REFERENCE CIRCUIT DIAGRAM ........................................................ 34
FIGURE 14: WAKE# BEHAVIORS.................................................................................................................... 35
FIGURE 15: DIMENSIONS OF THE RECEPTACLE RF CONNECTORS (UNIT: MM).................................... 40
FIGURE 16: MECHANICALS OF U.FL-LP MATING PLUGS ........................................................................... 41
FIGURE 17: SPACE FACTOR OF MATING PLUGS (UNIT: MM)..................................................................... 41
FIGURE 18: REFERENCED HEATSINK DESIGN ........................................................................................... 61
FIGURE 19: MECHANICAL DIMENSIONS OF EC21 MINI PCIE .................................................................... 62
FIGURE 20: STANDARD DIMENSIONS OF MINI PCI EXPRESS................................................................... 63
FIGURE 21: DIMENSIONS OF THE MINI PCI EXPRESS CONNECTOR (MOLEX 679105700).................... 64

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1Introduction
This document defines EC21 Mini PCIe module, and describes its air interfaces and hardware interfaces
which are connected with customers’ applications.
This document helps customers quickly understand module interface specifications, electrical
characteristics, mechanical specifications and other related information of the module. To facilitate
application designs, it also includes some reference designs for customers’ reference. The document,
coupled with application notes and user guides, makes it easy to design and set up wireless applications
with EC21 Mini PCIe.

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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 EC21 Mini PCIe 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
EC21 Mini PCIe module provides data connectivity on LTE-FDD, LTE-TDD, DC-HSDPA, HSPA+, HSDPA,
HSUPA, WCDMA, EDGE and GPRS networks with PCI Express Mini Card 1.2 standard interface. It
supports embedded operating systems such as Linux, Android etc., and also provides audio, high-speed
data transmission and GNSS functionalities for customers’ applications.
EC21 Mini PCIe module can be applied in the following fields:
PDA and Laptop Computer
Remote Monitor System
Vehicle System
Wireless POS System
Intelligent Meter Reading System
Wireless Router and Switch
Other Wireless Terminal Devices

EC21 Mini PCIe contains Telematics version and Data-only version. Telematics version supports voice
and data functions, while Data-only version only supports data function.
NOTE

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2.2. Description of Module Series
EC21 Mini PCIe series contains 10 variants, and are listed in the following table.
Table 1: Description of EC21 Mini PCIe
Module Series
Description
EC21-E Mini PCIe
Support GSM: 900/1800MHz
Support WCDMA: B1/B5/B8
Support LTE-FDD: B1/B3/B5/B7/B8/B20
Support LTE/WCDMA receive diversity
Support GNSS1)
Support digital audio2)
EC21-A Mini PCIe
Support WCDMA: B2/B4/B5
Support LTE-FDD: B2/B4/B12
Support LTE/WCDMA receive diversity
Support GNSS1)
Support digital audio2)
EC21-V Mini PCIe
Support LTE-FDD: B4/B13
Support LTE receive diversity
Support GNSS1)
Support digital audio2)
EC21-AUT Mini PCIe
Support WCDMA: B1/B5
Support LTE-FDD: B1/B3/B5/B7/B28
Support LTE/WCDMA receive diversity
Support GNSS1)
Support digital audio2)
EC21-AU Mini PCIe3)
Support GSM: 850/900/1800/1900MHz
Support WCDMA: B1/B2/B5/B8
Support LTE-FDD: B1/B2/B3/B4/B5/B7/B8/B28
Support LTE-TDD: B40
Support LTE/WCDMA receive diversity3)
Support GNSS1)
Support digital audio2)
EC21-J Mini PCIe
Support LTE-FDD: B1/B3/B8/B18/B19/B26
Support LTE receive diversity
Support digital audio2)
EC21-KL Mini PCIe
Support LTE-FDD: B1/B3/B5/B7/B8
Support LTE receive diversity
Support digital audio2)

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1. 1) GNSS function is optional.
2. 2) Digital audio (PCM) function is only supported on Telematics version.
3. 3) B2 band on EC21-AU Mini PCIe and EC21-AUX Mini PCIe module does not support Rx-diversity.
2.3. Key Features
The following table describes the detailed features of EC21 Mini PCIe module.
Table 2: Key Features of EC21 Mini PCIe
EC21-EU Mini PCIe
Support GSM: 900/1800MHz
Support WCDMA: B1/B8
Support LTE-FDD: B1/B3/B7/B8/B20/B28A
Support LTE/WCDMA receive diversity
Support GNSS1)
Support digital audio2)
EC21-EC Mini PCIe
Support LTE-FDD: B1/B3/B7/B8/B20/B28A
Support WCDMA: B1/B8
Support GSM: 900/1800MHz
Support LTE/WCDMA receive diversity
Support digital audio2)
EC21-AUX Mini PCIe3)
Support GSM: 850/900/1800/1900MHz
Support WCDMA: B1/B2/B4/B5/B8
Support LTE-FDD: B1/B2/B3/B4/B5/B7/B8/B28
Support LTE-TDD: B40
Support LTE/WCDMA receive diversity3)
Support GNSS1)
Support digital audio2)
Features
Description
Function Interface
PCI Express Mini Card 1.2 Standard Interface
Power Supply
Supply voltage: 3.0V~3.6V
Typical supply voltage: 3.3V
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
NOTES

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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 1.4/3/5/10/15/20MHz 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 42Mbps (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)
Internet Protocol Features
Support TCP/UDP/PPP/FTP/FTPS/HTTP/HTTPS/NTP/PING/QMI/NITZ/
SMTP/SSL/MQTT/CMUX/SMTPS/MMS*/FILE* protocols protocols
Support PAP (Password Authentication Protocol) and CHAP (Challenge
Handshake Authentication Protocol) protocols which are usually used for
PPP connection
SMS
Text and PDU modes
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
UART Interfaces
Main UART:
Support RTS and CTS hardware flow control
Baud rate can reach up to 230400bps, 115200bps by default
Used for AT command communication and data transmission

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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.
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
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, firmware
upgrade, software debugging, GNSS NMEA output and voice over USB.
Support USB serial drivers for: Windows 7/8/8.1/10, Linux 2.6~5.4, Android
4.x/5.x/6.x/7.x/8.x/9.x, etc.
Antenna Connectors
Include main antenna, diversity antenna and GNSS antenna receptacle
connectors
Rx-diversity (Optional)
Support LTE/WCDMA Rx-diversity
GNSS Features
Gen8C Lite of Qualcomm
Protocol: NMEA 0183
Data update rate: 1Hz by default
AT Commands
Compliant with 3GPP TS 27.007, 27.005 and Quectel enhanced AT
commands
Physical Characteristics
Size: (51.0±0.15)mm ×(30.0±0.15)mm ×(4.9±0.2)mm
Weight: approx. 9.8g
Temperature Range
Operation temperature range: -35°C to +75°C 1)
Extended temperature range: -40°C to +80°C 2)
Storage temperature range: -40°C to +90°C
Firmware Upgrade
Upgrade via USB interface or DFOTA*
RoHS
All hardware components are fully compliant with EU RoHS directive
NOTES

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2.4. Functional Diagram
The following figure shows the block diagram of EC21 Mini PCIe.
EC21
Module
PCM&I2C
Mini PCI Express
Interface
USB
W_DISABLE#
PERST#
LED_WWAN#
Main
Antenna
Connector
VCC
Main
Antenna
VBAT
GNSS
Antenna
Connector
GNSS
Antenna
Boost
Circuit
Diversity
Antenna
Connector
Diversity
Antenna
WAKE#
UART
DTR
RI
(U)SIM
Figure 1: Functional Diagram

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3Application Interfaces
The physical connections and signal levels of EC21 Mini PCIe comply with PCI Express Mini Card
Electromechanical Specification. This chapter mainly describes the definition and application of the
following interfaces/pins of EC21 Mini PCIe.
Power supply
(U)SIM interface
USB interface
UART interface
PCM and I2C interfaces
Control and indication signals
3.1. Pin Assignment
The following figure shows the pin assignment of EC21 Mini PCIe module. The top side contains EC21
module and antenna connectors.
BOT
TOP
Pin Name Pin No.
WAKE# 1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
41
43
45
47
49
51
RESERVED
RESERVED
RESERVED
GND
UART_RX
UART_TX
GND
RI
RESERVED
GND
UART_CTS
UART_RTS
GND
GND
DTR
RESERVED
GND
GND
VCC_3V3
VCC_3V3
GND
PCM_CLK
PCM_DOUT
PCM_DIN
PCM_SYNC
Pin Name
Pin No.
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
VCC_3V3
GND
NC
USIM_VDD
USIM_DATA
USIM_CLK
USIM_RST
RESERVED
GND
W_DISABLE#
PERST#
RESERVED
GND
NC
I2C_SCL
I2C_SDA
GND
USB_DM
USB_DP
GND
LED_WWAN#
USIM_PRESENCE
RESERVED
NC
GND
VCC_3V3
Pin 1 Pin 2
Pin 51 Pin 52
Figure 2: Pin Assignment

LTE Standard Module Series
EC21 Mini PCIe Hardware Design
EC21_Mini_PCIe_Hardware_Design 19 / 67
3.2. Pin Description
The following tables show the pin definition and description of the 52 pins on EC21 Mini PCIe.
Table 3: I/O Parameters Definition
Table 4: Pin Description
Type
Description
DI
Digital Input
DO
Digital Output
IO
Bidirectional
OC
Open Collector
PI
Power Input
PO
Power Output
Pin No.
Mini PCI Express
Standard Name
EC21 Mini PCIe
Pin Name
I/O
Description
Comment
1
WAKE#
WAKE#
OC
Output signal used to wake
up the host
2
3.3Vaux
VCC_3V3
PI
3.0V~3.6V, typically 3.3V
DC supply
3
COEX1
RESERVED
Reserved
It is
prohibited to
be pulled up
to high level
before
startup.
4
GND
GND
3.0V~3.6V, typically 3.3V
DC supply
5
COEX2
RESERVED
Reserved
It is
prohibited to
be pulled up
to high level
before
startup.