Quectel EC20 Mini PCIe Hardware Design

Contact Information

Quectel Wireless Solutions Co., Ltd.

Office 501, Building 13, No.99, Tianzhou Road, Shanghai, China, 200233

Tel: +86 21 5108 6236

Mail: info@quectel.com

For local office information, please visit: www.quectel.com/support/salesupport.aspx

For technical support or documentation errors, please visit: www.quectel.com/support/techsupport.aspx or Email: Support@quectel.com

General Notes

Quectel offers this information as a service to its customers. The information provided is based upon customers' requirements. Quectel makes every effort to ensure the quality of the information it makes available. Quectel does not make any warranty as to the information contained herein, and does not accept any liability for any injury, loss or damage of any kind incurred by use of or reliance upon the information. The information supplied herein is subject to change without prior notice.

Copyright

This information contained herein is proprietary technical information of Quectel Co., Ltd. Transmittable, reproduction, dissemination and editing of this document as well as utilization of its contents are forbidden without permission. Offenders will be held liable for payment of damages. All rights are reserved in the event of a patent grant or registration of a utility model or design.

Copyright © Quectel Wireless Solutions Co., Ltd. 2015. All rights reserved.

About the Document

History

1. Introduction

This document defines the EC20 Mini PCIe module and describes its hardware interfaces, which are connected with your application and air interfaces. It helps users quickly understand the interface specifications, electrical and mechanical details, and related product information of the EC20 Mini PCIe module. To facilitate its application in different fields, relevant reference design documents are also provided. Coupled with application notes and user guides for the EC20 Mini PCIe module, users can easily design and set up mobile applications.

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 the EC20 Mini PCIe module. Manufacturers of the cellular terminal should provide this safety information to users and operating personnel and incorporate these guidelines into all manuals supplied with the product. Failure to comply with these precautions may result in Quectel not being liable for customer issues.

• Driving Safety: Give full attention to driving to reduce the risk of an accident. Using a mobile while driving, even with a hands-free kit, can cause distraction and lead to an accident. Comply with laws and regulations restricting the use of wireless devices while driving. [Vehicle Icon]
• Aircraft Safety: Switch off the cellular terminal or mobile before boarding an aircraft. Ensure it is switched off. The operation of wireless appliances in an aircraft is forbidden to prevent interference with communication systems. Consult airline staff regarding the use of wireless devices on board, if your device offers an Airplane Mode which must be enabled prior to boarding. [Airplane Icon]
• Medical Facilities: Switch off your wireless device when in hospitals or clinics or other health care facilities. These requests are designed to prevent possible interference with sensitive medical equipment. [Hospital/Health Icon]
• Emergency Calls: Cellular terminals or mobiles operate over radio frequency signals and cellular networks and cannot be guaranteed to connect in all conditions (e.g., no mobile fee or invalid SIM card). If you are in such a condition and need emergent help, remember to use the emergency call function. To make or receive calls, the cellular terminal or mobile must be switched on and in an area with adequate cellular signal strength. [SOS Icon]
• RF Interference: Your cellular terminal or mobile contains a transmitter and receiver. When ON, it receives and transmits radio frequency energy. RF interference can occur if it is used close to a TV set, radio, computer, or other electric equipment. [Heartbeat/Signal Icon]
• Explosive Atmospheres: In locations with potentially explosive atmospheres, obey all posted signs to turn off wireless devices. This includes areas like fueling stations, below decks on boats, fuel or chemical transfer or storage facilities, and areas where the air contains chemicals or particles such as grain, dust, or metal powders. [Explosion/Hazard Icon]

2. Product Concept

2.1. General Description

The EC20 Mini PCIe module provides data connectivity on FDD-LTE, WCDMA, and GSM networks using a PCI Express Mini Card 1.2 standard interface. It supports embedded operating systems like WinCE, Linux, and Android, and offers audio, high-speed data transmission, and GPS/GLONASS functionality for applications.

The EC20 Mini PCIe module can be applied in the following fields:

• PDAs and Laptop Computers
• Remote Monitor Systems
• Vehicle Systems
• Wireless POS Systems
• Intelligent Meter Reading Systems
• Wireless Routers and Switches
• Other Wireless Terminal Devices

This chapter generally introduces the following aspects of the EC20 Mini PCIe module:

• Product Series
• Key Features
• Functional Diagram

2.2. Description of Product Series

The following table shows the product series of the EC20 Mini PCIe module.

2.3. Key Features

The following table describes the detailed features of the EC20 Mini PCIe module.

2.4. Functional Diagram

The following figure shows a block diagram of the EC20 Mini PCIe module. It illustrates the main components and interfaces:

Diagram Description: A block diagram showing the EC20 Module at the center, connected to the Mini PCI Express Interface (VCC, USB, PCM&I2C, UART, USIM, W_DISABLE#, PERST#, DTR, RI, LED_WWAN#). It also shows connections to Main Antenna Interface, GNSS Antenna Interface, and Diversity Antenna Interface. A USIM Holder is shown as optional.

3. Application Interface

3.1. General Description

The physical connections and signal levels of the EC20 Mini PCIe comply with PCI Express Mini CEM specifications. This chapter describes the interface definitions and applications of the EC20 Mini PCIe:

• Power supply
• USIM interface
• USB interface
• UART interface
• PCM&I2C interface
• Control signals
• Antenna interface

3.2. EC20 Mini PCIe Interface

3.2.1. Definition of Interface

The following tables show the pin assignments of the EC20 Mini PCIe on the 52-pin application.

3.2.2. Pin Assignment

The following figure shows the pin assignment of the EC20 Mini PCIe module. The top side contains the EC20 module and antenna connectors.

Diagram Description: A pin assignment diagram for the 52-pin Mini PCIe connector, showing pin numbers and corresponding pin names for both the Mini PCI Express Standard and EC20 Mini PCIe Pin Name. It indicates connections for power, ground, UART, USIM, I2C, USB, control signals, and PCM.

3.3. Power Supply

The following table shows the VCC_3V3 pins and ground pins.

The typical supply voltage of EC20 Mini PCIe is 3.3V. In 2G networks, the input peak current may reach up to 2.7A during transmission. Therefore, the power supply must be able to provide enough current, and a bypass capacitor of no less than 470µF with low ESR should be used to prevent voltage dropping.

The following figure shows a reference design of the power supply. The precision of resistors R2 and R3 is 1%, and capacitor C3 requires low ESR.

Diagram Description: A reference circuit diagram for power supply, featuring an LDO (MIC29302WU), resistors (R1, R2, R3, R4), and capacitors (C1, C2, C3, C4, C5) connected to VCC_3V3 and GND.

3.4. USIM Card Interface

The following table shows the pin definition of the USIM card interface.

EC20 Mini PCIe supports 1.8V and 3.0V USIM cards. The following figure shows the reference design of the 6-pin USIM card.

Diagram Description: A reference circuit for the 6-pin USIM card, showing connections between the module (USIM_VDD, USIM_DATA, USIM_CLK, USIM_RST, GND) and a USIM Holder (VCC, GND, RST, CLK, VPP, IO), including series resistors (22R) and decoupling capacitors (33pF, 100nF).

To enhance reliability and availability of the USIM card in your application, follow these criteria:

• Keep the USIM card layout as close to the module as possible, with trace lengths less than 200mm.
• Keep USIM card signals away from RF and power supply alignment.
• Maintain a ground and USIM_VDD width of at least 0.5mm for consistent electric potential.
• The decoupling capacitor for USIM_VDD should be less than 1uF and placed near the USIM holder.
• To avoid cross-talk between USIM_DATA and USIM_CLK, keep them separated and shield them with ground.
• For ESD protection, add TVS diodes. Use 22R resistors in series between the module and USIM card to suppress EMI and enhance ESD protection. 33pF capacitors are for filtering GSM850/EGSM900 interference. Ensure the USIM peripheral circuit is close to the USIM card holder.
• A pull-up resistor on the USIM_DATA line can improve anti-jamming capability for long traces and sensitive applications, and should be placed close to the holder.

3.5. USB Interface

The following table shows the pin definition of the USB interface.

EC20 Mini PCIe is compliant with USB 2.0 specification and can only be used as a slave device. It supports high-speed (480Mbps) and full-speed (12Mbps) modes. The USB interface is used for AT command communication, data transmission, GNSS NMEA output, software debug, and firmware upgrade. The following figure shows the reference circuit of the USB interface.

Diagram Description: A reference circuit for the USB interface, showing connections between the Module (USB_DM, USB_DP, GND) and an MCU (VCC_MCU, VCC, USB_DM, USB_DP, GND), including a differential layout and a NM_2pF capacitor.

To ensure USB interface design compliance with the USB 2.0 specification, follow these principles:

• Route USB signal traces as differential pairs with total grounding. The impedance of USB differential traces should be 90Ω.
• Avoid routing signal traces under crystals, oscillators, magnetic devices, and RF signal traces. Route USB differential traces on an inner layer with ground shielding, and ensure shielding on all sides.
• If using a USB connector, keep ESD components as close to the connector as possible. Pay attention to the junction capacitance of ESD components on USB data lines; typically, this value should be less than 2pF.

3.6. UART Interface

The following table shows the pin definition of the UART interface.

The UART interface supports baud rates of 9600, 19200, 38400, 57600, 115200, and 230400bps, with a default of 115200bps. This interface can be used for AT communication.

EC20 Mini PCIe is designed as the DCE, and the DCE-DTE connection of the UART interface is shown below.

Diagram Description: A diagram illustrating the DCE-DTE connection of the UART interface. It shows EC20 Mini PCIe (DCE) with UART_RX, UART_TX, DTR, RI, GND pins connected to the Application (DTE) with corresponding TXD, RXD, DTR, RI, GND pins.

The following figure is an example of connection between EC20 Mini PCIe and a PC. Since the UART interface does not support RS-232 levels, an RS-232 level translator IC must be inserted between the module and the PC. A RS-232 level shifter SN65C3238 from Texas Instruments is recommended. The following figure shows the reference design of the RS232 level match circuit.

Diagram Description: A reference circuit diagram for RS232 level matching, showing connections between EC20 Mini PCIe (UART_TX, UART_RX, DTR, RI, GND) and a DB9 connector (PC) via an SN65C3238 level shifter IC. The diagram details the IC's pins (DIN1-5, DOUT1-5, ROUT1-3, RIN1-3) and their connections.

3.7. PCM and I2C Interface

The following table shows the pin definition of the PCM interface, applicable for audio codec design.

EC20 Mini PCIe provides one PCM digital interface supporting 8-bit A-law and µ-law, and 16-bit linear data formats, with the following modes:

• Primary mode (short sync, works as either master or slave)
• Auxiliary mode (long sync, works as master only)

In primary mode, data is sampled on the falling edge of PCM_CLK and transmitted on the rising edge. The PCM_SYNC falling edge represents the MSB. In this mode, PCM_CLK supports 128kHz, 256kHz, 512kHz, 1024kHz, 2048kHz, and 4096kHz. The following figure shows the timing relationship in primary mode with 8kHz PCM_SYNC and 2048kHz PCM_CLK.

Diagram Description: Timing diagram for Primary Mode showing PCM_CLK, PCM_SYNC, PCM_DOUT, and PCM_DIN signals over a 125us interval, illustrating MSB and LSB data transmission.

In auxiliary mode, data is sampled on the falling edge of PCM_CLK and transmitted on the rising edge, while the PCM_SYNC rising edge represents the MSB. In this mode, the PCM interface operates with a 128kHz PCM_CLK and an 8kHz, 50% duty cycle PCM_SYNC only. The following figure shows the timing relationship in auxiliary mode with 8kHz PCM_SYNC and 128kHz PCM_CLK.

Diagram Description: Timing diagram for Auxiliary Mode showing PCM_CLK, PCM_SYNC, PCM_DOUT, and PCM_DIN signals over a 125us interval, illustrating MSB and LSB data transmission with specific clock and sync configurations.

Clock and mode can be configured by AT command. The default configuration is master mode using short sync data format with 2048kHz PCM_CLK and 8kHz PCM_SYNC.

The following figure shows the reference design of the PCM interface with an external codec IC (such as ALC5616).

Diagram Description: A reference circuit diagram for PCM interface application with an audio codec. It shows connections between the Module (PCM_CLK, PCM_SYNC, PCM_DOUT, PCM_DIN, I2C_SCL, I2C_SDA) and a Codec IC (BCLK, FS, DACIN, ADCOUT, SCLK, SDIN) and microphone/speaker connections (MIC_BIAS, MIC+, MIC-, SPKOUT+, SPKOUT-).

3.8. Control Signals

The following table shows the pin definition of control signals.

3.8.1. RI Signal

The RI signal can be used to wake up the host. When URC returns, the RI pin will behave as follows:

Diagram Description: A simple timing diagram showing the RI signal transitioning from High to Low over 120ms, labeled as 'URC return'.

3.8.2. DTR Signal

The DTR signal supports sleep control function; driving it to a low level will wake up the module. The AT command AT+QCFG="pwrsavedtr" is used to disable the sleep control function.

3.8.3. W_DISABLE# Signal

EC20 Mini PCIe provides the W_DISABLE# signal to disable wireless communications via hardware operation. The following table shows the radio operational states of the module. Refer to document [2] for related AT commands.

3.8.4. PERST# Signal

The PERST# signal can be used to force a hardware reset on the card. You can reset the module by driving PERST# to a low level voltage for more than 150ms and then releasing it. The reset scenario is illustrated in the following figure.

Diagram Description: A timing diagram for module resetting. It shows the VCC_3V3 voltage level and the PERST# signal. PERST# is shown going from a high level (VIH ≥ 2.3V) to a low level (VIL ≤ 0.5V) for over 150ms, indicating a 'RESETTING' state, before returning to a high level for the 'RUNNING' state. The module status transitions from RUNNING to RESETTING and back to RUNNING.

3.8.5. LED_WWAN# Signal

The LED_WWAN# signal of EC20 Mini PCIe indicates the network status of the module and can absorb current up to 40mA. To reduce the LED current, a resistor must be placed in series with the LED. The LED emits light when the LED_WWAN# output signal is active low.

Diagram Description: A reference circuit diagram for the LED_WWAN# signal. It shows the LED_WWAN# output connected through a resistor (R) to an LED, which is then connected to VCC. The diagram indicates that the LED lights up when LED_WWAN# is active low.

The following table shows the indications of network status based on the LED_WWAN# signal.

3.9. Antenna Interface

The EC20 Mini PCIe antenna interfaces include a main LTE/UMTS/GSM antenna interface, a LTE/UMTS Rx-diversity antenna interface, and a GNSS antenna interface. All these connectors are ECT818000117.

The following figure shows the overall sizes of the RF connector.

Diagram Description: Dimensions of the RF connector (Unit: mm), showing a central signal pin and surrounding ground connections, with specific measurements and tolerances indicated.

You can use the U.FL-LP serial connectors listed in the following figure to match the ECT818000117. For more details, please visit www.hirose.com.

Diagram Description: Mechanical specifications of U.FL-LP connectors (Part No. U.FL-LP-040, U.FL-LP-066, U.FL-LP(V)-040, U.FL-LP-062, U.FL-LP-088). It includes details on Mated Height, Applicable cable size, Weight, and RoHS compliance.

4. Electrical and Radio Characteristics

4.1. General Description

This chapter mainly describes the following electrical and radio characteristics of the EC20 Mini PCIe:

• Power supply requirements
• IO requirements
• Current consumption
• RF characteristics
• GNSS receiver
• ESD characteristics

4.2. Power Supply Requirements

The input voltage of EC20 Mini PCIe is 3.3V±9%, as specified by PCI Express Mini CEM Specifications 1.2. The following table shows the power supply requirements of EC20 Mini PCIe.

4.3. IO Requirements

The following table shows the IO requirements of EC20 Mini PCIe.

4.4. RF Characteristics

The following tables show the output power and receiving sensitivity of conducted RF of the EC20 Mini PCIe module.

Output Power of Conducted RF

Conducted RF Receiving Sensitivity

4.5. GNSS Receiver

The EC20 Mini PCIe integrates a GNSS receiver that supports Qualcomm's gpsOne Gen8A (GPS and GLONASS) and can be used with Qualcomm gpsOneXTRA technology (a form of A-GNSS). This technology downloads XTRA files from internet servers to enhance the Time To First Fix (TTFF). XTRA files contain predicted GPS and GLONASS satellite coordinates and clock biases valid for up to 7 days. It is recommended to download XTRA files every 1-2 days. Additionally, the EC20 Mini PCIe supports the standard NMEA-0183 protocol and can output NMEA messages at 1Hz via the USB NMEA interface.

The EC20 Mini PCIe GNSS engine is switched off by default. It must be switched on using an AT command. Refer to document [3] for more details on GNSS engine technology and configurations. A passive antenna should be used.

4.6. ESD Characteristics

The following table shows the ESD characteristics of the EC20 Mini PCIe.

5. Mechanical Dimensions

5.1. General Description

This chapter mainly describes the dimensions of the EC20 Mini PCIe:

• Mechanical Dimensions of EC20 Mini PCIe
• Standard Dimensions of Mini PCI Express
• Packaging

5.2. Mechanical Dimensions of EC20 Mini PCIe

Diagram Description: Mechanical dimensions of the EC20 Mini PCIe module (Unit: mm). It shows top, side, and bottom views with detailed measurements for length, width, height, pin positions, and mounting holes.

5.3. Standard Dimensions of Mini PCI Express

The following figure shows the standard dimensions of Mini PCI Express. Please refer to document [1] for detailed A and B.

Diagram Description: Standard dimensions of the Mini PCI Express form factor (Unit: mm). It illustrates top and bottom views with key measurements, pin numbering references (odd pins on top, even pins on bottom), and mounting hole details.

5.4. Packaging

The EC20 Mini PCIe is packaged in trays. Each tray contains 10 modules. The smallest package of EC20 Mini PCIe contains 100 modules.

6. Appendix Reference

Table 18: Related Documents

Table 19: Terms and Abbreviations