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SIM Tech SIMCom SIM900-DS Hardware Design

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Summary of Contents for SIM Tech SIMCom SIM900-DS

  • Page 1 SIM900-DS_Hardware Design_V1.00...
  • Page 2 Smart Machine Smart Decision SIM900-DS Hardware Design Document Title 1.00 Version 2013-01-20 Date Release Status SIM900-DS_Hardware Design_V1.00 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.

  • Page 3: Table Of Contents

    Smart Machine Smart Decision Contents Contents........................3 1 Introduction ......................8 2 SIM900-DS Overview .................... 8 SIM900-DS Key Features....................8 Operating Modes.......................10 SIM900-DS Functional Diagram ..................11 3 Package Information.................... 12 Pin out Diagram ........................12 Pin Description ........................13 Package Dimensions......................15 4 Application Interface ................... 17 Power Supply........................17 4.1.1 Minimizing Voltage Drop of VBAT ....................
  • Page 4 Smart Machine Smart Decision LCD Display/SPI Interface ....................31 PCM Interface ........................32 4.10 ADC ............................32 4.11 RI Behaviors ........................32 4.12 Network Status Indication ....................33 4.13 General Purpose Input/Output (GPIO)................34 4.14 External Reset ........................34 4.15 C Bus ..........................35 4.16 Antenna Interface ......................35 5 Electrical, Reliability and Radio Characteristics..........
  • Page 5 Smart Machine Smart Decision Table Index Table 1: SIM900-DS key features ........................8 Table 2: Coding schemes and maximum net data rates over air interface ............10 Table 3: Overview of operating modes......................10 Table 4: Pin description ............................ 13 Table 5: The Current consumption of Minimum Functionality Mode .............
  • Page 6 Smart Machine Smart Decision Figure Index Figure 1: SIM900-DS functional diagram ......................11 Figure 2: SIM900-DS pin out diagram (Top view) ..................12 Figure 3: Dimensions of SIM900-DS（Unit: mm）..................15 Figure 4: Recommended PCB footprint outline（Unit: mm） ................ 16 Figure 5: Reference circuit of the LDO power supply..................17 Figure 6: Reference circuit of the DC-DC power supply .................
  • Page 7 Smart Machine Smart Decision Version History Date Version Description of change Author 2013-01-20 1.00 Origin Zhaojuntao SIM900-DS_Hardware Design_V1.00 2013-01-20...

  • Page 8: Introduction

    Smart Machine Smart Decision 1 Introduction This document describes SIM900-DS hardware interface in great detail. This document can help user to quickly understand SIM900-DS interface specifications, electrical and mechanical details. With the help of this document and other SIM900-DS application notes, users can use SIM900-DS to design various applications quickly.
  • Page 9 Smart Machine Smart Decision Class 4 (2W) at GSM 850 and EGSM 900 Transmitting power Class 1 (1W) at DCS 1800 and PCS 1900 GPRS multi-slot class 10（default） GPRS connectivity GPRS multi-slot class 8 (option) Normal operation: -30°C ~ +80°C Temperature range Restricted operation: -40°C ~ -30°C and +80 °C ~ +85°C Storage temperature -45°C ~ +90°C...

  • Page 10: Operating Modes

    Smart Machine Smart Decision Table 2: Coding schemes and maximum net data rates over air interface Coding scheme 1 timeslot 2 timeslot 4 timeslot CS-1 9.05kbps 18.1kbps 36.2kbps CS-2 13.4kbps 26.8kbps 53.6kbps CS-3 15.6kbps 31.2kbps 62.4kbps CS-4 21.4kbps 42.8kbps 85.6kbps Operating Modes The table below summarizes the various operating modes of SIM900-DS.

  • Page 11: Sim900-Ds Functional Diagram

    Smart Machine Smart Decision SIM900-DS Functional Diagram The following figure shows a functional diagram of SIM900-DS: The GSM baseband engine Flash The GSM radio frequency part The antenna interface The other interfaces Power Radio supply Frequency Power management unit Digital Interface Analog Interface SIM1 Audio...

  • Page 12: Package Information

    Smart Machine Smart Decision 3 Package Information Pin out Diagram Figure 2: SIM900-DS pin out diagram (Top view) SIM900-DS_Hardware Design_V1.00 2013-01-20...

  • Page 13: Pin Description

    Smart Machine Smart Decision Pin Description Table 4: Pin description Pin name Pin number Description Comment Power supply VBAT 55,56,57 Power supply It is recommended to VRTC Power supply for RTC connect with a battery or a capacitor (e.g. 4.7uF). VDD_EXT 2.8V output power supply If it is unused, keep open.
  • Page 14 Smart Machine Smart Decision GPIO1 GPIO1 Serial port Receive data Transmit data Request to send Clear to send If these pins are unused, keep open. Data carrier detect Ring indicator Data terminal ready Debug interface DBG_TXD debugging and upgrading If these pins are unused, firmware keep open.

  • Page 15: Package Dimensions

    Smart Machine Smart Decision Package Dimensions Figure 3: Dimensions of SIM900-DS（Unit: mm） SIM900-DS_Hardware Design_V1.00 2013-01-20...
  • Page 16 Smart Machine Smart Decision Figure 4: Recommended PCB footprint outline（Unit: mm） Note: Keep copper out of area A. Do not place via in area B to avoid short circuit between the via on customer board and the test points on the bottom side of the module. SIM900-DS_Hardware Design_V1.00 2013-01-20...

  • Page 17: Application Interface

    Smart Machine Smart Decision 4 Application Interface Power Supply The power supply range of SIM900-DS 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 18: Minimizing Voltage Drop Of Vbat

    Smart Machine Smart Decision Figure 7: VBAT voltage drop during transmit burst 4.1.1 Minimizing Voltage Drop of VBAT When designing the power supply in user’s application, pay special attention to power losses. Ensure that the input voltage never drops below 3.1V even when current consumption rises to 2A in the transmit burst. If the power voltage drops below 3.1V, the module may be shut down automatically.

  • Page 19: Power Down Sim900-Ds

    Smart Machine Smart Decision Figure 10: Powered on/down module using button The power on scenarios is illustrated as following figure. Figure 11: Timing of power on module When power on procedure is completed, SIM900-DS will send following URC to indicate that the module is ready to operate at fixed baud rate.
  • Page 20 Smart Machine Smart Decision Figure 12: Timing of power down SIM900-DS by PWRKEY This procedure makes the module log off from the network and allows the software to enter into a secure state to save data before completely shut down. Before the completion of the power down procedure, the module will send URC: NORMAL POWER DOWN At this moment, AT commands can not be executed any more, and only the RTC is still active.

  • Page 21: Restart Sim900-Ds By Pwrkey Pin

    Smart Machine Smart Decision 4.2.2.4 Over-temperature or Under-temperature Power down The module will constantly monitor the temperature of the module, If the temperature > +80℃, the following URC will be reported: +CMTE: 1 If the temperature < -30℃, the following URC will be reported: +CMTE:-1 If the temperature >...

  • Page 22: Sleep Mode 1 (At+Csclk=1)

    Smart Machine Smart Decision 0: minimum functionality. 1: full functionality (default). 4: flight mode (disable RF function). Minimum functionality mode minimizes the current consumption to the lowest level. If SIM900-DS is set to minimum functionality by “AT+CFUN=0”, the RF function and SIM card function will be disabled. In this case, the serial port is still accessible, but all AT commands correlative with RF function and SIM card function will not be accessible.

  • Page 23: Wake Up Sim900-Ds From Sleep Mode 2 (At+Csclk=2)

    Smart Machine Smart Decision 4.3.5 Wake Up SIM900-DS from Sleep Mode 2 (AT+CSCLK=2) When SIM900-DS is in sleep mode 2 (AT+CSCLK=2), the following methods can wake up the module: Send data to SIM900-DS via serial port. Receive a voice or data call from network. Receive a SMS from network.

  • Page 24: Serial Interfaces

    Smart Machine Smart Decision Coin-type rechargeable battery is recommended, such as XH414H-IV01E form Seiko can be used. Typical charge-discharge curves for this battery are shown in the following figure. Figure 17: Seiko XH414H-IV01E Charge-Discharge Characteristic Serial Interfaces SIM900-DS provides two unbalanced asynchronous serial ports. One is the serial port and the other is the debug port.

  • Page 25: Function Of Serial Port And Debug Port

    Smart Machine Smart Decision MODULE (DCE) CUSTOMER (DTE) Serial port Serial port1 RING Debug port Serial port2 DBG_TX DBG_RX Figure 19: Connection of RXD and TXD only 4.5.1 Function of Serial Port and Debug Port Serial port: Full modem device. Contains data lines TXD and RXD, hardware flow control lines RTS and CTS, status lines DTR, DCD and Serial port can be used for CSD FAX, GPRS service and AT communication.

  • Page 26: Software Upgrade And Debug

    Smart Machine Smart Decision 4.5.2 Software Upgrade and Debug Refer to the following figure for debugging and upgrading software. Figure 20: Connection for software upgrading and debugging The serial port and the debug port support the CMOS level. If user connects the module to the computer, the level shifter should be added between the DCE and DTE.

  • Page 27: Microphone Interfaces Configuration

    Smart Machine Smart Decision Figure 22: Speaker with amplifier reference circuit 4.6.2 Microphone Interfaces Configuration These components should be placed to microphone as close as possible The lines in bold type should 10pF 33pF be accorded to differential ANTI signal layout rules MIC_1P 10pF 33pF...

  • Page 28: Earphone Interface Configuration

    Smart Machine Smart Decision 4.6.3 Earphone Interface Configuration Figure 24: Earphone reference circuit 4.6.4 Audio Electronic Characteristics Table 6: Microphone Input Characteristics Parameter Unit Working Voltage Working Current External Microphone Load Resistance kΩ Internal biasing DC Characteristics Differential input THD <1% at F=1KHz; pre-amp gain = 20 dB; 15.9 mVrms voltage...

  • Page 29: Sim Card Interface

    Smart Machine Smart Decision SIM Card Interface 4.7.1 SIM Card Application SIM900-DS provides two SIM card interfaces. The interface complies with the GSM Phase 1 specification and the new GSM Phase 2+ specification for FAST 64 kbps SIM card. Both 1.8V and 3.0V SIM card are supported. The SIM interface is powered from an internal regulator in the module.

  • Page 30: Design Considerations For Sim Card Holder

    Smart Machine Smart Decision 4.7.2 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. Figure 27: Amphenol C707 10M006 5122 SIM card holder Table 8: Pin description (Amphenol SIM card holder) Pin name Signal...

  • Page 31: Lcd Display/Spi Interface

    Smart Machine Smart Decision Figure 28: Molex 91228 SIM card holder Table 9: Pin description (Molex SIM card holder) Pin name Signal Description SIM_VDD SIM card power supply SIM_RST SIM card reset SIM_CLK SIM card clock Connect to GND Connect to GND Not connect SIM_DATA SIM card data I/O...

  • Page 32: Pcm Interface

    Smart Machine Smart Decision PCM Interface SIM900-DS provides PCM interface ,which can communicate with external digital audio interface, such as BT, CODEC. This interface only supports master mode. The PCM interface provides a FIFO to handle the difference in clock rates to effectively decouple the two interfaces to ensure no data is lost.

  • Page 33: Network Status Indication

    Smart Machine Smart Decision HIGH Establish the call Hang up the call Idle Ring Figure 29: RI behaviour of voice calling as a receiver HIGH Establish the call Hang up the call Idle Ring Figure 30: RI behaviour of data calling as a receiver Figure 31: RI behaviour of URC or receive SMS However, if the module is used as caller, the RI will remain high.

  • Page 34: General Purpose Input/Output (Gpio)

    Smart Machine Smart Decision Table 12: Status of the NETLIGHT pin Status SIM900-DS behavior SIM900-DS is not running 64ms On/ 800ms Off SIM900-DS not registered the network 64ms On/ 3000ms Off SIM900-DS registered to the network 64ms On/ 300ms Off GPRS communication is established A reference circuit is recommended in the following figure: Figure33: Reference circuit of NETLIGHT...

  • Page 35: I 2 C Bus

    Smart Machine Smart Decision Figure 34: Reset timing This pin is already pulled up in the module, so the external pull-up resistor is not necessary. A 100nF capacitor close to the NRESET pin is strongly recommended. A reference circuit is shown in the following figure. Figure 35: Reset reference design circuit NOTE: It is recommended to cut off the VBAT power supply directly instead of using external reset pin when SIM900-DS can not respond to the AT command “AT+CPOWD=1”...
  • Page 36 Smart Machine Smart Decision MODULE RF test connector Matching circuit Antenna feed pad RF_ANT J101 R101 R102 J102 C101 C102 Figure 36: Antenna matching circuit In this figure, the components R101,R102,C101 and C102 is used for antenna matching, the components’ value only can be got after the antenna tuning.

  • Page 37: Electrical, Reliability And Radio Characteristics

    Smart Machine Smart Decision 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 SIM900-DS. Table 14: Absolute maximum ratings Symbol Parameter Unit...

  • Page 38: Sim Card Interface Characteristics

    Smart Machine Smart Decision SIM Card Interface Characteristics Table 17: 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 VDD_EXT Characteristics Table 18: VDD_EXT characteristics Symbol Parameter Unit...

  • Page 39: Current Consumption (Vbat = 3.8V)

    Smart Machine Smart Decision Symbol Parameter Unit VRTC input voltage 2.00 3.00 3.15 RTC-IN VRTC input current RTC-IN VRTC output voltage 3.00 RTC-OUT VRTC output current RTC-OUT Current Consumption (VBAT = 3.8V) Table 21: Current consumption Symbol Parameter Conditions Value Unit VRTC current VBAT disconnects.

  • Page 40: Electro-Static Discharge

    Smart Machine Smart Decision DCS1800 PCL=0 PCS1900 PCL=7 PCL=15 Peak current During Tx burst VBAT-peak * 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 SIM900-DS is an ESD sensitive component, so more attention should be paid to the procedure of handling and packaging.
  • Page 41 Smart Machine Smart Decision ±3 ±4 ±3 ±4 ±3 ±4 ±3 ±4 ±3 ±4 ±3 ±4 ±3 ±4 ±5 ±6 ±5 ±6 ±5 ±6 19-31 ±5 ±6 Table 24 : SIM900-DS DCS1800 and PCS1900 conducted RF output power DCS1800 and PCS1900 Tolerance (dB) for conditions Nominal output power (dBm) Normal...

  • Page 42: Module Rf Receive Sensitivity

    Smart Machine Smart Decision 30dBm, and at the maximum power level, the output power tolerance should not exceed +/-2dB under normal condition and +/-2.5dB under extreme condition. 5.10.2 Module RF Receive Sensitivity The following table shows the module’s conducted receive sensitivity, it is tested under static condition. Table 25 : SIM900-DS conducted RF receive sensitivity Frequency Receive sensitivity（Typical）...

  • Page 43: Manufacturing

    Smart Machine Smart Decision 6 Manufacturing Top and Bottom View of SIM900-DS Figure 37: Top and bottom view of SIM900-DS Note: These test points are only used for module manufacturing and testing. They are not for customer using. The following figure marked the information of SIM900-DS module. Figure 38: Module information SIM900-DS_Hardware Design_V1.00 2013-01-20...

  • Page 44: Typical Solder Reflow Profile

    Smart Machine Smart Decision Table 27: Illustration of module information Item Description Logo of SIMCom Module name Module part number Module serial number and bar code Module IMEI1 and bar code Module IMEI2 and bar code Typical Solder Reflow Profile Figure 39: Typical Solder Reflow Profile For details about secondary SMT, please refer to document [10].

  • Page 45: Appendix

    Smart Machine Smart Decision Appendix A. Related Documents Table 28 : Related documents Document name Remark SIM900-DS_Application SIM900-DS Application Note Note AN_SIM900_TCPIP TCP/IP Applications User Manual SIM900_Multiplexer User SIM900 Multiplexer User Manual Application Note Manual_Application Note AN_SIM900 SIM900 Series Update Tool User Guide Series_Update Tool_UGD SIM900_Embedded SIM900 Embedded AT Application Note...

  • Page 46: Terms And Abbreviations

    Smart Machine Smart Decision B. Terms and Abbreviations Table 29 : 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 Dual SIM Enhanced Full Rate EGSM...

  • Page 47: Safety Caution

    Smart Machine Smart Decision UART Universal Asynchronous Receiver & Transmitter 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...
  • Page 48 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 SIM900-DS_Hardware Design_V1.00 2013-01-20...

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