SimCom SIM900D Hardware Design
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SimCom SIM900D Hardware Design

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Summary of Contents for SimCom SIM900D

  • Page 1 SIM900D_Hardware Design_V2.02...
  • 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

    Monitoring Power Supply ........................19 Power on/down Scenarios ........................19 4.2.1 Power on SIM900D..........................19 4.2.1.1 Turn on SIM900D Using the PWRKEY Pin (Power on) ..............19 4.2.1.2 Turn on the SIM900D using the VCHG signal ..................20 4.2.2 Power down SIM900D........................21 4.2.2.1...
  • Page 4 Module RF Receive Sensitivity......................45 5.9.3 Module Operating Frequencies ......................46 Manufacturing ..............................47 Top and Bottom View of SIM900D ....................... 47 Typical Solder Reflow Profile........................ 47 Appendix ................................48 A. Related Documents............................48 B. Terms and Abbreviations ..........................49 C.
  • Page 5 TABLE 23: CURRENT CONSUMPTION ........................42 TABLE 24: THE ESD CHARACTERISTICS (TEMPERATURE: 25℃, HUMIDITY: 45 %) ........43 TABLE 25: SIM900D GSM 900 AND GSM 850 CONDUCTED RF OUTPUT POWER ..........44 TABLE 26: SIM900D DCS 1800 AND PCS 1900 CONDUCTED RF OUTPUT POWER..........45 TABLE 27: SIM900D CONDUCTED RF RECEIVE SENSITIVITY ................
  • Page 6 FIGURE 12: POWERED ON/DOWN MODULE USING BUTTON ................20 FIGURE 13: TIMING OF POWER ON MODULE......................20 FIGURE 14: TIMING OF POWER DOWN SIM900D BY PWRKEY ................21 FIGURE 15: TIMING OF RESTART SIM900D ......................23 FIGURE 16: SIM900D WITH BATTERY CHARGER AND PACK CONNECTION............ 25 FIGURE 17: RTC SUPPLY FROM CAPACITOR......................

  • Page 7: Version History

    §3.4.1.1Update the Figure8: Timing of turn on system using PWRKEY Jing.zhou §3.4.2.1Update the Figure9: Timing of turn off system using PWRKEY §4.2Update the Table25: SIM900D conducted RF receive sensitivity 2010-06-24 1.03 §3.8, Modify the VRTC pin connection when backup is not needed.

  • Page 8: Introduction

    Programmable general purpose input and output. The SPI display interface will give users the flexibility to develop customized applications. SIM900D is designed with power saving technique so that the current consumption is as low as 1.0mA in sleep mode. SIM900D integrates TCP/IP protocol and extended TCP/IP AT commands which are very useful for data transfer applications.
  • Page 9 Smart Machine Smart Decision SIM900D 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...

  • Page 10: Operating Modes

    Smart Machine Smart Decision Firmware upgrade Firmware upgradeable by debug port. SIM900D does work at this temperature, but some radio frequency characteristics may deviate from the GSM specification. Table 2: Coding schemes and maximum net data rates over air interface Coding scheme...

  • Page 11: Sim900D Functional Diagram

    The module will systematically enter Charge-only mode when a charger and battery are mode connected to a switched-off SIM900D. In the mode, the module does not search for network and has limited AT commands available. The module also can enter Charge-only mode from Charge mode during normal operation by normally shutdown the module.

  • Page 12: Figure 1: Sim900D Functional Diagram

    Serial Port Serial Battery GPIO Interface interface interface Debug/upgrading program Transceiver Power Amplifier Analog Controller With PMU 32.768KHz SIM interface Digital Baseband LCD interface 26MHz Flash+SRAM PWRKEY Analog interface Audio interface Charger Figure 1: SIM900D functional diagram SIM900D_Hardware Design_V2.02 2012-05-07...

  • Page 13: Package Information

    Smart Machine Smart Decision 3 Package Information Pin out Diagram DBG_RXD DBG_TXD STATUS SIM_DATA SIM_CLK SIM_RST SIM900D SIM_VDD TOP VIEW KBR0 PWRKEY DISP_CLK DISP_DATA VRTC DISP_D/C Figure 2: SIM900D pin out diagram (Top view) SIM900D_Hardware Design_V2.02 2012-05-07...

  • Page 14: Pin Description

    Smart Machine Smart Decision Pin Description Table 4: Pin description Pin name Pin number Description Comment Power supply VBAT 38,39 Power supply It is recommended to VRTC Power supply for RTC connect with a battery or a capacitor (e.g. 4.7uF). AGND Analog GND 17,30,31,32,...
  • Page 15 Smart Machine Smart Decision Request to send keep open. Clear to send Data carrier detect Ring indicator Data terminal ready Debug interface DBG_TXD If these pins are unused, For debugging and upgrading firmware keep open. DBG_RXD SIM interface Voltage supply for SIM card. Support SIM_VDD signals 1.8V or 3V SIM card...

  • Page 16: Package Dimensions

    Smart Machine Smart Decision Package Dimensions Following shows the Mechanical dimensions of SIM900D (top view, side view and bottom view). Figure 3: SIM900D top mechanical dimensions (Unit: mm) Figure 4: SIM900D bottom mechanical dimensions (Unit: mm) SIM900_Hardware Design_V2.02 2012-05-07...

  • Page 17: Figure 5: Sim900D Side Mechanical Dimensions (Unit: Mm)

    Smart Machine Smart Decision Figure 5: SIM900D side mechanical dimensions (Unit: mm) FOOT PRINT RECOMMENDATION: Figure 6: Recommended PCB decal (Unit: mm) Note: Keep copper out of area A,B,C. Do not place via in area A, B and C to avoid short circuit between via on customer board and the test points on the bottom side of the module.

  • Page 18: Application Interface

    Power Supply The power supply range of SIM900D is from 3.2V to 4.8V. 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 19: Minimizing Voltage Drop Of Vbat

    Turn on SIM900D Using the PWRKEY Pin (Power on) User can power on SIM900D by pulling down the PWRKEY pin for at least 1 second and release. This pin is already pulled up to 3V in the module internal, so external pull up is not necessary. Reference circuit is shown as below.

  • Page 20: Turn On The Sim900D Using The Vchg Signal

    The SIM900D will be automatically turned on when a charger is connected to the switched-off SIM900D of which VBAT pin voltage is greater than 3.2V. SIM900D will go into the Charge-only Mode. In this mode, the module does not register to the network, and has only a few AT commands available. For detailed information please refer to chapter 3.5.

  • Page 21: Power Down Sim900D

    Smart Machine Smart Decision (please refer to Figure 13 Timing of power on module), the SIM900D will power up and go into Charge mode during normal operation. In this case, SIM900D sends out result code as following: From CHARGE-ONLY MODE to NORMAL MODE In Charge mode during normal operation, all operations and AT commands are available.

  • Page 22: Over-Voltage Or Under-Voltage Power Down

    The AT command “AT+CMTE” could be used to read the temperature when the module is running. For details please refer to document [1]. 4.2.3 Restart SIM900D by PWRKEY Pin When the module works normally, if the user wants to restart the module, follow the procedure below: Power down the module.

  • Page 23: Power Saving Mode

    Power Saving Mode SIM900D have two sleep modes: sleep mode 1 is enabled by hardware pin DTR; sleep mode 2 is only enabled by serial port regardless of the DTR. In sleep mode, the current of module is very low. The AT command “AT+CFUN=<fun>”...

  • Page 24: Wake Up Sim900D From Sleep Mode 1 (At+Csclk=1)

    Note: For SIM900D, It is requested to set AT command “AT+CSCLK=2” to enable the sleep mode 2; the default value is 0, which can not make the module to enter sleep mode. For more details please refer to document [1].

  • Page 25: Battery Pack Characteristics

    4.4.1 Battery pack characteristics SIM900D has optimized the charging algorithm for the Li-Ion battery that meets the characteristics listed below. The maximum charging voltage of the Li-Ion battery pack is 4.2V and the recommended capacity is 1100mAh. The Battery packs with more than 1100 mAh capacity will cost more time for charging.

  • Page 26: Implemented Charging Technique

    Fast charge: If there is a charger supply and battery present and the battery is not in DDLO and UVLO, SIM900D will enter fast charge state. Fast charge is controlled by the software to make the current/voltage regulation. The charging scheme for the Li-Ion battery is constant current (about 550mA) first, followed by constant voltage charging once SIM900D_Hardware Design_V2.02...

  • Page 27: Operating Modes During Charging

    Note: VBAT can not provide more than 5mA current while SIM900D module is during the DDLO charge state. In other words it is strongly recommended that VBAT should not be the main power supply in the application subsystem if SIM900D DDLO charging state occurs.

  • Page 28: Charger Requirements

    Charging in normal mode. In Charge-only mode, the default value is 0. 4.4.5 Charger requirements Following is the requirements of charger for SIM900D. - Simple transformer power plug - Output voltage: 5.0V-6V - Minimum supply current: 750mA - A 10V peak voltage is allowed for maximum 1ms when charging current is switched off.

  • Page 29: Serial Interfaces

    Figure 20: Seiko XH414H-IV01E Charge-Discharge Characteristic Serial Interfaces SIM900D provides two unbalanced asynchronous serial ports. One is the serial port and the other is the debug port. The module is designed as a DCE (Data Communication Equipment). The following figure shows the connection between module and client (DTE).

  • Page 30: Function Of Serial Port And Debug Port

    Autobauding only supports the following baud rates: 1200, 2400, 4800, 9600, 19200, 38400 and 57600bps The default setting is autobauding. Autobauding allows SIM900D 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, user must firstly send character “A”...

  • Page 31: Software Upgrade And Debug

    For details about software upgrading, please refer to document [4]. Audio Interfaces SIM900D provides two analog inputs, MIC1P/1N and MIC2P/2N, which could be used for electret microphone. The module also provides two analog outputs, SPK1P/1N and SPK2P/2N. The output can directly drive 32Ω...

  • Page 32: Speaker Interface Configuration

    Smart Machine Smart Decision 4.7.1 Speaker Interface Configuration Figure 24: Speaker reference circuit Figure 25: Speaker with amplifier reference circuit 4.7.2 Microphone Interfaces Configuration Figure 26 : Microphone reference circuit SIM900D_Hardware Design_V2.02 2012-05-07...

  • Page 33: Earphone Interface Configuration

    Smart Machine Smart Decision 4.7.3 Earphone Interface Configuration Figure 27: Earphone reference circuit 4.7.4 Audio Electronic Characteristics Table 9: Microphone Input Characteristics Parameter Unit Working Voltage Working Current External Microphone Load Resistance kΩ Internal biasing DC Characteristics Differential input <1% 15.9 mVrms voltage...

  • Page 34: Sim Card Interface

    Smart Machine Smart Decision Table 10: Audio Output Characteristics Parameter Conditions Unit RL=32Ω THD=0.1% RL=32Ω THD=1% Normal Output swing Output(SPK) Voltage (single ended) Output swing Voltage (differential) SIM Card Interface 4.8.1 SIM Card Application The SIM interface complies with the GSM Phase 1 specification and the new GSM Phase 2+ specification for FAST 64 kbps SIM card.

  • Page 35: Design Considerations For Sim Card Holder

    Figure 29: Reference circuit of the 6-pin SIM card holder 4.8.2 Design Considerations for SIM Card Holder 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.

  • Page 36: Table 11: Pin Description (Amphenol Sim Card Holder)

    Connect to GND Not connect SIM_DATA SIM card data I/O 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 31: Molex 91228 SIM card holder Table 12: Pin description (Molex SIM card holder)

  • Page 37: Lcd Display/Spi Interface

    Detect SIM card presence LCD Display/SPI Interface SIM900D provides a serial LCD display interface. It could also be used as SPI interface in the embedded AT application. For details about embedded AT application, please refer to document [6]. Note: This function is not supported in the standard firmware. If user wants this function, the firmware must be customized.

  • Page 38: Network Status Indication

    Smart Machine Smart Decision The behavior of the RI pin is shown in the following figure when the module is used as a receiver. HIGH Establish the call Hang up the call Idle Ring Figure 32: RI behaviour of voice calling as a receiver HIGH Establish the call Hang up the call...

  • Page 39: General Purpose Input/Output (Gpio)

    4.13 General Purpose Input/Output (GPIO) SIM900D 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 40: Antenna Interface

    Smart Machine Smart Decision 4.15 Antenna Interface SIM900D provides a RF antenna interface. The customer’s antenna should be located in the customer’s main board and connect to module’s antenna pad through microstrip line or other type RF trace which impendence must be controlled in 50Ω.

  • Page 41: Electrical, Reliability And Radio Characteristics

    5 Electrical, Reliability and Radio Characteristics Absolute Maximum Ratings The absolute maximum ratings stated in following table are stress ratings under non-operating conditions. Stresses beyond any of these limits will cause permanent damage to SIM900D. Table 17: Absolute maximum ratings Symbol...

  • Page 42: Sim_Vdd Characteristics

    Smart Machine Smart Decision Table 20: SIM card interface characteristics   Symbol Parameter Unit High-level input current Low-level input current High-level input voltage Low-level input voltage High-level output voltage Low-level output voltage SIM_VDD Characteristics Table 21: SIM_VDD characteristics   Symbol Parameter Unit 2.75...

  • Page 43: Electro-Static Discharge

    * In above table the current consumption value is the typical one of the module tested in laboratory. In the mass production stage, there may be differences among each individual. Electro-Static Discharge SIM900D 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. ℃...

  • Page 44: Radio Characteristics

    The following table shows the module conducted output power, it is followed by the 3GPP TS 05.05 technical specification requirement. Table 25: SIM900D GSM 900 and GSM 850 conducted RF output power GSM 900 and EGSM 850 Tolerance (dB) for conditions...

  • Page 45: Module Rf Receive Sensitivity

    Smart Machine Smart Decision Table 26 : SIM900D DCS 1800 and PCS 1900 conducted RF output power DCS 1800 and PCS 1900 Tolerance (dB) for conditions Nominal output power (dBm) Normal Extreme ±2 ±2.5 ±3 ±4 ±3 ±4 ±3 ±4 ±3...

  • Page 46: Module Operating Frequencies

    Smart Machine Smart Decision Table 27 : SIM900D conducted RF receive sensitivity Frequency Receive sensitivity（Typical） Receive sensitivity(Max) GSM850 -109dBm -107dBm EGSM900 -109dBm -107dBm DCS1800 -109dBm -107dBm PCS1900 -109dBm -107dBm 5.9.3 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.

  • Page 47: Manufacturing

    Smart Machine Smart Decision 6 Manufacturing Top and Bottom View of SIM900D Figure 38: Top and bottom view of SIM900D These test points are only used for module manufacturing and testing. They are not for customer using. Typical Solder Reflow Profile Figure 39: Typical Solder Reflow Profile For details about secondary SMT, please refer to document [9].

  • Page 48: Appendix

    Applications Note About SIM900 Audio SIM900_Embedded SIM900 Embedded AT Application Note Application Note AN_Serial Port Application Note About Serial Port AN_SIM900D-TE PCB Application Note About SIM900D-TE PCB Layout & Schematic Layout & Schematic for Reference Module Module secondary SMT User Guide secondary-SMT-UGD [10]...

  • Page 49: Terms And Abbreviations

    Smart Machine Smart Decision B. Terms and Abbreviations Table 30 : Terms and Abbreviations Abbreviation Description Analog-to-Digital Converter Adaptive Multi-Rate Coding Scheme Circuit Switched Data Clear to Send Data Terminal Equipment (typically computer, terminal, printer) Data Terminal Ready Discontinuous Transmission Enhanced Full Rate EGSM Enhanced GSM...

  • Page 50: Safety Caution

    Smart Machine Smart Decision Unsolicited Result Code USSD Unstructured Supplementary Service Data Phonebook abbreviations SIM fix dialing phonebook SIM last dialing phonebook (list of numbers most recently dialed) Mobile Equipment list of unanswered MT calls (missed calls) SIM (or ME) own numbers (MSISDNs) list Mobile Equipment list of received calls SIM phonebook Not connect...
  • Page 51 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 3235 3300 Fax: +86 21 3235 3301 URL: www.sim.com/wm SIM900D_Hardware Design_V2.02 2012-05-07...

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