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SimCom SIM808 Hardware Design

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Summary of Contents for SimCom SIM808

  • Page 1 SIM808_Hardware Design_V1.00...
  • Page 2 Document Control ID General Notes SIMCom offers this information as a service to its customers, to support application and engineering efforts that use the products designed by SIMCom. The information provided is based upon requirements specifically provided to SIMCom by the customers. SIMCom has not undertaken any independent search for additional relevant information, including any information that may be in the customer’s possession.

  • Page 3: Table Of Contents

    Power Saving Mode..........................26 4.3.1 Function Mode ............................ 27 4.3.2 Sleep Mode (AT+CSCLK=1) ......................27 4.3.3 Wake Up SIM808 from Sleep Mode (AT+CSCLK=1) ..............27 Charging Interface ..........................28 4.4.1 Battery Pack Characteristics........................ 28 4.4.2 Recommended Battery Pack ....................... 28 4.4.3...
  • Page 4 Module RF Receive Sensitivity ....................... 59 6.10.3 Module Operating Frequencies......................60 Manufacturing ..............................61 Top and Bottom View of SIM808......................61 Typical Solder Reflow Profile ........................ 61 The Moisture Sensitivity Level ......................62 Baking Requirements ..........................62 Appendix ................................63 SIM808_Hardware Design_V1.00...
  • Page 5 B. Terms and Abbreviations ..........................64 C. Safety Caution ..............................65 Table Index TABLE 1: SIM808 GSM/GPRS ENGINE KEY FEATURES ..................10 TABLE 2: GPS ENGINE PERFORMANCE ........................12 TABLE 3: CODING SCHEMES AND MAXIMUM NET DATA RATES OVER AIR INTERFACE ......12 TABLE 4: OVERVIEW OF OPERATING MODES......................
  • Page 6 ......................56 TABLE 46: THE ESD CHARACTERISTICS (TEMPERATURE: 25℃, HUMIDITY: 45 %) ........57 TABLE 47: SIM808 GSM 900 AND GSM 850 CONDUCTED RF OUTPUT POWER ..........58 TABLE 48: SIM808 DCS 1800 AND PCS 1900 CONDUCTED RF OUTPUT POWER..........58 TABLE 49: SIM808 CONDUCTED RF RECEIVE SENSITIVITY ................
  • Page 7 FIGURE 11: POWERED ON/DOWN MODULE USING BUTTON ................22 FIGURE 12: TIMING OF POWER ON MODULE......................23 FIGURE 13: TIMING OF POWER ON MODULE......................23 FIGURE 14: TIMING OF POWER DOWN SIM808 BY PWRKEY ................24 FIGURE 15: RESET CIRCUIT............................26 FIGURE 16: RESET TIMING SEQUENCE........................26 FIGURE 17: SIM808 WITH BATTERY CHARGER AND PACK CONNECTION............
  • Page 8 FIGURE 49: RF_SYNC SIGNAL DURING TRANSMIT BURST ................51 FIGURE 50: GSM ANTENNA MATCHING CIRCUIT ....................51 FIGURE 51: GPS ANTENNA MATCHING CIRCUIT....................53 FIGURE 52: TOP AND BOTTOM VIEW OF SIM808 ....................61 FIGURE 53: TYPICAL SOLDER REFLOW PROFILE ....................61 SIM808_Hardware Design_V1.00...

  • Page 9: Version History

    Smart Machine Smart Decision Version History Date Version Description of change Author 2014-03-27 1.00 Origin ShengWu.Sun Xuegang.Wang SIM808_Hardware Design_V2.00 2014.03.27...

  • Page 10: Introduction

    Support PWM and ADC. PCM/SPI/SD card interface, only one function can be accessed synchronously. (Default function is PCM). SIM808 is designed with power saving technique so that the current consumption is as low as 1mA in sleep mode (GPS engine is powered down).
  • Page 11 Smart Machine Smart Decision can search the 4 frequency bands automatically. The frequency bands also can be set by AT command “AT+CBAND”. For details, please refer to document [1]. Compliant to GSM Phase 2/2+ Class 4 (2W) at GSM 850 and EGSM 900 Transmitting power Class 1 (1W) at DCS 1800 and PCS 1900 GPRS multi-slot class 12（default）...

  • Page 12: Table 2: Gps Engine Performance

    Smart Machine Smart Decision Firmware upgrade Firmware upgrading by USB interface. Table 2: GPS engine Performance Performance Parameter Description Type Unit Horizontal Position Autonomous <2.5 Accuracy(1) Velocity Without Aid Accuracy(2) DGPS 0.05 Acceleration Without Aid Accuracy DGPS 0.05 Timing Accuracy Dynamic Maximum Altitude 18000...

  • Page 13: Operating Modes

    Smart Machine Smart Decision Operating Modes The table below summarizes the various operating modes of SIM808. Table 4: Overview of operating modes Mode Function Module will automatically go into sleep mode if the conditions of sleep mode are enabling and there is no on air and no hardware interrupt (such as GSM/GPRS GPIO interrupt or data on serial port).

  • Page 14: Sim808 Functional Diagram

    Smart Machine Smart Decision SIM808 Functional Diagram The following figure shows a functional diagram of SIM808: The GSM baseband engine The GPS engine Flash The GSM radio frequency part The antenna interface The other interfaces Figure 1: SIM808 functional diagram SIM808_Hardware Design_V1.00...

  • Page 15: Package Information

    Smart Machine Smart Decision 3 Package Information Pin out Diagram Figure 2: SIM808 pin out diagram (Top view) SIM808_Hardware Design_V1.00 2014.03.27...

  • Page 16: Pin Description

    Pin Description Table 5: Pin description Pin name Pin number Description Comment Power supply SIM808 supplies 3 VBAT pins, and the power Zener diode range is from 3.4V to 4.4V. Power supply Strongly VBAT 4,5,6 should provide sufficient current so that the recommended to anti module can work normally;...
  • Page 17 Smart Machine Smart Decision GPIO GPIO5 Programmable general purpose input and output. GPIO6 NETLIGHT Network status Can not multiplex with GPIO function. STATUS Power on status Serial port Data terminal ready Ring indicator Data carrier detect Keep floating Clear to send unused.

  • Page 18: Package Dimensions

    Smart Machine Smart Decision Other signal RESET Reset input(Active low) Time Mark outputs timing pulse related to 1PPS If unused, keep open. receiver time Package Dimensions Figure 3: Dimensions of SIM808（Unit: mm） SIM808_Hardware Design_V1.00 2014.03.27...

  • Page 19: Figure 4: Recommended Pcb Footprint Outline（Unit: Mm

    Smart Machine Smart Decision Figure 4: Recommended PCB footprint outline（Unit: mm） SIM808_Hardware Design_V1.00 2014.03.27...

  • Page 20: Gsm Application Interface

    4 GSM Application Interface Power Supply The power supply range of SIM808 is from 3.4V to 4.4V.Recommended voltage is 4.0V.The transmitting burst will cause voltage drop and the power supply must be able to provide sufficient current up to 2A. For the VBAT input, a bypass capacitor (low ESR) such as a 100 µF is strongly recommended.

  • Page 21: Power Supply Pin

    Figure 7: Reference circuit of the DC-DC power supply The single 3.7V Li-ion cell battery can be connected to SIM808 VBAT pins directly. But the Ni-Cd or Ni-MH battery must be used carefully, since their maximum voltage can rise over the absolute maximum voltage of the module and damage it.

  • Page 22: Monitoring Power Supply

    Turn on SIM808 Using the PWRKEY Pin (Power on) User can power on SIM808 by pulling down the PWRKEY pin for at least 1 second and release. This pin is already pulled up to VBAT in the module internal, so external pull up is not necessary. Reference circuit is shown as below.

  • Page 23: Figure 12: Timing Of Power On Module

    The power on scenarios is illustrated as following figure. Figure 12: Timing of power on module When power on procedure is completed, SIM808 will send following URC to indicate that the module is ready to operate at fixed baud rate.

  • Page 24: Power Down Sim808

    Power down SIM808 by the PWRKEY Pin User can power down SIM808 by pulling down the PWRKEY pin for at least 1 second and release. Please refer to the power on circuit. The power down scenario is illustrated in following figure.

  • Page 25: Reset Function

    Reset Function SIM808 also has a RESET pin (pin 16) used to reset the module. This function is used as an emergency reset only when AT command “AT+CPOWD=1” and the POWER_ON pin has no effect. User can pull the RESET pin to ground, then the module will reset.

  • Page 26: Power Saving Mode

    User can control SIM808 module to enter or exit the sleep mode (AT+CSCLK=1) by DTR signal. When DTR is in high level and without interrupt (on air and hardware such as GPIO interrupt or data in serial port), SIM808 will enter sleep mode automatically. In this mode, SIM808 can still receive paging or SMS from network but the serial port is not accessible.

  • Page 27: Function Mode

    SMS from network but the serial port is not accessible. Note: For SIM808, it requests to set AT command “AT+CSCLK=1” and ensure DTR at high level to enable the sleep mode ; the default value is 0, which can not make the module to enter sleep mode. For more details please refer to document [1].

  • Page 28: Charging Interface

    Smart Machine Smart Decision Charging Interface SIM808 has integrated a charging circuit inside the module for Li-Ion batteries charging control, which make it very convenient for user’s applications that support battery charging. A common connection is shown in the following figure:...

  • Page 29: Implemented Charging Technique

    Constant voltage mode (CV) and over-voltage protection (OV): As the battery is charged up and over 4.05V, the SIM808 will enter CV mode. While the batter voltage actually reaches 4.2V, the charging current is gradually decreased step by step until stop charging.

  • Page 30: Charger Requirements

    Smart Machine Smart Decision 4.4.5 Charger Requirements Following is the requirements of charger for SIM808: Simple transformer power plug Output voltage: 5.0V~7V Minimum supply current: 800mA A 10V peak voltage is allowed for maximum 1ms when charging current is switched off.

  • Page 31: Serial Port And Usb Interface

    Figure 21: Seiko XH414H-IV01E charge-discharge characteristic Serial Port and USB Interface SIM808 provides one unbalanced asynchronous serial port. The module is designed as a DCE (Data Communication Equipment). The following figure shows the connection between module and client (DTE). Table 10: Serial port and USB pin definition...

  • Page 32: Function Of Serial Port

    Autobauding only supports the following baud rates: 1200, 2400, 4800, 9600, 19200, 38400, 57600 and 115200bps The default setting is autobauding. Autobauding allows SIM808 to automatically detect the baud rate of the host device. Pay more attention to the following requirements: Synchronization between DTE and DCE: When DCE powers on with autobauding enabled, firstly, user must send character “A”...

  • Page 33: Figure 23: Level Converting By Resistor

    Smart Machine Smart Decision change the resistors in the following figure from 5.6K to 14K. Figure 23: Level converting by resistor If the voltage of UART is 3V or3.3V, user also can use following reference circuits: Figure 24: Isolation circuit by diodes te: when a diode used to isolate voltage cross, customer should notice that there’s voltage drop on the diode.

  • Page 34: Usb Interface

    Smart Machine Smart Decision VDD_EXT Customer Module VDD_EXT MCUVDD MCUTXD Figure 26: RX level converting by transistor Note: The recommend Transistors’ part numbers are 2SC4617TLR and PBHV8115Z. when update firmware via the TXD/RXD circuit as figure 25 and figure 26 shows, customer should make sure the VDD_EXT has voltage output, or a external LDO should be added to power VDD_EXT.

  • Page 35: Software Upgrade And Debug

    If customer upgrading firmware via the USB port, SIM808 must be powered first, then connect VBUS, USB_DP, USB_DM and GND to PC. There is no need to operate PWRKEY pin in the whole procedure, when SIM808 detects VBUS and could communicate normally by USB_DP and USB_DM, module will enter USB download mode automatically.

  • Page 36: Audio Interfaces

    Figure 31: RI behaviour as a caller Audio Interfaces SIM808 provides one analog input, which could be used for electret microphone. The module also provides one analog output. The output can directly drive 32Ω receiver. Table 14: Audio interface definition...

  • Page 37: Speaker Interface Configuration

    Smart Machine Smart Decision In order to improve audio performance, the following reference circuits are recommended. The audio signals have to be layout according to differential signal layout rules as shown in following figures. 4.8.1 Speaker Interface Configuration These components should be placed to speaker as close as possible The lines in bold type should...

  • Page 38: Audio Electronic Characteristics

    Smart Machine Smart Decision 4.8.3 Audio Electronic Characteristics Table 15: Microphone input characteristics Parameter Unit Mic biasing voltage Working Current Input impedance(differential) KΩ Idle channel noise Input level:-40dBm0 SINAD Input level:0dBm0 Table 16: Audio output characteristics parameter Conditions Unit Normal output =32 Ω...

  • Page 39: Bluetooth

    Smart Machine Smart Decision Bluetooth SIM808 supports Bluetooth function, customer only needs to design the Bluetooth antenna, and then customer can operate Bluetooth conveniently by AT commands. For the detail commands about Bluetooth please refer to document [1] Fully compliant with Bluetooth specification3.0 + EDR...

  • Page 40: Sim Card Application

    Smart Machine Smart Decision 4.10.1 SIM Card Application Table 17: SIM pin definition Name function SIM_VDD Voltage supply for SIM card. Support 1.8V or 3V SIM card SIM_DATA SIM data input/output SIM_CLK SIM clock SIM_RST SIM reset SIM_PRE SIM card detection It is recommended to use an ESD protection component such as ON (http://onsemi.com ) SMF12CT1G.

  • Page 41: Sim Card Design Consideration

    Add some TVS and the parasitic capacitance should not exceed 50pF, and 22Ω resistor in serials the SIM signal could enhance ESD protection. 4.10.3 Design Considerations for SIM Card Holder For 8 pins SIM card holder, SIMCom recommends to use Molex 91228.User can visit http://www.molex.com more information about the holder. Figure 38: Molex 91228 SIM card holder SIM808_Hardware Design_V1.00...

  • Page 42: Table 18: Pin Description (Molex Sim Card Holder)

    SIM card data I/O SIM_PRE Detect SIM card presence For 6-pin SIM card holder, SIMCom recommends to use Amphenol C707 10M006 5122 .User can visit http://www.amphenol.com for more information about the holder. Figure 39: Amphenol C707 10M006 5122 SIM card holder...

  • Page 43: Pcm Interface

    PCM_IN PCM data input PCM_SYNC PCM synchrony PCM_CLK PCM clock SIM808 PCM interface only supports master mode, data length is 16 bits (linear), and PCM clock rate is 256 KHz. Table 21: PCM pin specification Feature specification Line Interface Format...

  • Page 44: Pcm Interface

    Figure 40: PCM reference circuit 4.11.3 LCD Display/SPI Interface SIM808 provides a serial interface. It could be used as SPI interface in the embedded AT application. For details about embedded AT application, please refer to document [1]. Refer to the following figure for SPI design:...

  • Page 45: Sd Card Interface

    4.12 Keypad Interface SIM808 consists of 4 keypad column outputs and 4 keypad row inputs, and it can support two kinds of connections, the traditional 4*4 keypad matrix and the extended 4*4*2 keypad matrix.

  • Page 46: Figure 44: Extended Keypad Reference Circuit

    Smart Machine Smart Decision Module supports a new keypad connection, it can support 4*4*2 amount 32 keypads, meet full keyboard demand, and the connection diagram is as follow: Figure 44: Extended keypad reference circuit Note: Do not change the 20KΩ resistor in the diagram. Customer should add a resistor to enhance the ESD performance and the value of resistor should be less than 1KΩ, the connection diagram is shown in follow figure as an example.

  • Page 47: I2C Bus

    Note: Multiplex Function need different software version . 4.13 I2C BUS The SIM808 provides an I2C interface, it can be driven by either the master or slave and conform to the I2C specification. It has the following features: Compliant master mode operation SIM808_Hardware Design_V1.00...

  • Page 48: General Purpose Input/Output (Gpio)

    4.13.1 General Purpose Input/Output (GPIO) SIM808 provides 2 GPIO pins. The output voltage level of the GPIO can be set by the AT command “AT+ SGPIO”. The input voltage level of the GPIO can also be read by the AT command “AT+ SGPIO”. For more details, please refer to document [1].

  • Page 49: Pwm

    PWM2, multiplex with GPIO3 Note: SIM808 can only support 1 PWM synchronously, if customer set PIN 42 as PWM, so PIN41 can only be used as GPIO. PWM output frequency varies from 0 to 2KHz.Two 7-bit unsigned binary parameters are used for the output period and for the duty cycle.

  • Page 50: Network Status Indication

    Table 34: Status of the NETLIGHT pin Status SIM808 behavior SIM808 is not running 64ms On/ 800ms Off SIM808 not registered the network 64ms On/ 3000ms Off SIM808 registered to the network 64ms On/ 300ms Off PPP GPRS communication is established...

  • Page 51: Rf Synchronization Signal

    Smart Machine Smart Decision 4.18 RF Synchronization Signal The synchronization signal serves to indicate growing power consumption during the transmit burst. Table 36: Definition of the RF_SYNC pin Pin name Pin number Description RF_SYNC Transmit synchronization signal Note: Do not pull up RF_SYNC. The timing of the synchronization signal is shown in the following figure.

  • Page 52: Gps Application Interface

    PCB layout. For details about radio frequency trace layout, please refer to document [9]. 5 GPS Application Interface SIM808 provide a high-performance L1 GPS solution for cellular handset applications. The solution offers best-in-class acquisition and tracking sensitivity, Time-To-First-Fix (TTFF) and accuracy. The GPS engine supports both fully-autonomous operations for use in handheld consumer navigation devices and other standalone navigation systems.

  • Page 53: Gps Power On/Down Scenarios

    Smart Machine Smart Decision GPS Power on/down Scenarios 5.2.1 Power on GPS engine User can power on GPS engine by sending AT command “AT+CGPSPWR=1”. 5.2.2 Power down GPS engine User can power down GPS engine by sending AT command “AT+CGPSPWR=0”. GPS Antenna Interface 5.3.1 GPS Antenna Interface...

  • Page 54: Electrical, Reliability And Radio Characteristics

    Smart Machine Smart Decision Proper ground plane sizing is a critical consideration for small GPS antennas. Proper placement of the GPS antenna should always be the FIRST consideration in integrating the SIM808 GPS Module. If the customer’s design will allow for a ceramic RHCP patch antenna with an appropriately sized ground plane, and the patch is normally oriented towards the sky, then that particular solution usually works the best.

  • Page 55: Recommended Operating Conditions

    Smart Machine Smart Decision VBAT Peak Current VBUS These parameters are for digital interface pins, such as keypad, GPIO, I2C, UART, LCD and PCM. Recommended Operating Conditions Table 39 : Recommended operating conditions Symbol Parameter Unit VBAT Power supply voltage Operating temperature ℃...

  • Page 56: Sim_Vdd Characteristics

    Smart Machine Smart Decision 0.36 Low-level output voltage SIM_VDD Characteristics Table 42: SIM_VDD characteristics Symbol Parameter Unit Output voltage 1.80 Output voltage VDD_EXT Characteristics Table 43: VDD_EXT characteristics Symbol Parameter Unit Output voltage 2.70 2.80 2.95 Output current VRTC Characteristics Table 44: VRTC characteristics Symbol Parameter...

  • Page 57: Electro-Static Discharge

    Electro-Static Discharge SIM808 is an ESD sensitive component, so more attention should be paid to the procedure of handling and packaging. The ESD test results are shown in the following table. Table 46 : The ESD characteristics (Temperature: 25℃, Humidity: 45 %)

  • Page 58: Radio Characteristics

    ±5 ±6 ±5 ±6 ±5 ±6 19-31 ±5 ±6 Table 48 : SIM808 DCS 1800 and PCS 1900 conducted RF output power DCS 1800 and PCS 1900 Tolerance (dB) for conditions Nominal output power (dBm) Normal Extreme SIM808_Hardware Design_V1.00 2014.03.27...

  • Page 59: Module Rf Receive Sensitivity

    30dBm, and at the maximum power level, the output power tolerance should not exceed +/-2dB under normal condition and +/-2.5dB under extreme condition. 6.10.2 Module RF Receive Sensitivity The following table shows the module’s conducted receive sensitivity, it is tested under static condition. Table 49 : SIM808 conducted RF receive sensitivity Frequency Receive sensitivity（Typical） Receive sensitivity(Max)

  • Page 60: Module Operating Frequencies

    Smart Machine Smart Decision 6.10.3 Module Operating Frequencies The following table shows the module’s operating frequency range; it is followed by the 3GPP TS 05.05 technical specification requirement. Table 50 : SIM808 operating frequencies Frequency Receive Transmit GSM850 869 ~ 894MHz...

  • Page 61: Manufacturing

    Smart Machine Smart Decision 7 Manufacturing Top and Bottom View of SIM808 Figure 52: Top and Bottom View of SIM808 Typical Solder Reflow Profile Figure 53: Typical Solder Reflow Profile 《 》 Note: Please refer to Module secondary-SMT-UGD for more information about the module shipping and manufacturing.

  • Page 62: The Moisture Sensitivity Level

    Smart Machine Smart Decision The Moisture Sensitivity Level The moisture sensitivity level of SIM808 is 3. The module should be mounted within 168 hours after unpacking in the environmental conditions of temperature <30°C and relative humidity of <60% (RH). It is necessary to...

  • Page 63: Appendix

    LINE-IN input SIM900_Embedded SIM808 Embedded AT Application Note Application Note AN_Serial Port Application Note About Serial Port AN_SIM900-TE PCB Application Note About SIM808-TE PCB Layout & Schematic Layout & Schematic for Reference [10] Module Module secondary SMT User Guide secondary-SMT-UGD...

  • Page 64: Terms And Abbreviations

    Smart Machine Smart Decision B. Terms and Abbreviations Table 54 : Terms and Abbreviations Abbreviation Description Analog-to-Digital Converter Adaptive Multi-Rate Coding Scheme Circuit Switched Data Clear to Send Circular Error Probable Data Terminal Equipment (typically computer, terminal, printer) Data Terminal Ready Discontinuous Transmission Enhanced Full Rate EGSM...

  • Page 65: Safety Caution

    Smart Machine Smart Decision Real Time Clock Receive Direction Subscriber Identification Module SBAS Satellite Based Augmentation Systems Short Message Service Terminal Equipment, also referred to as DTE Transmit Direction UART Universal Asynchronous Receiver & Transmitter Unsolicited Result Code USSD Unstructured Supplementary Service Data WAAS Wide Area Augmentation System Phonebook abbreviations...
  • Page 66 Smart Machine Smart Decision GSM cellular terminals or mobiles operate over radio frequency signals and cellular networks and cannot be guaranteed to connect in all conditions, for example no mobile fee or a invalid SIM card. While you are in this condition and need emergent help, please remember using emergency calls. In order to make or receive calls, the cellular terminal or mobile must be switched on and in a service area with adequate cellular signal strength.
  • Page 67 Smart Machine Smart Decision Contact us: Shanghai SIMCom Wireless Solutions Ltd. Add: SIM Technology Building, No.633, Jinzhong Road,Changning District,Shanghai P.R. China 200335 Tel: +86 21 3252 3300 Fax: +86 21 3252 3301 URL: www.sim.com/wm SIM808_Hardware Design_V1.00 2014.03.27...

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