Telit Wireless Solutions GE863-PY, GE863-QUAD 2General Design Rules, Electrical design Guidelines

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GE863-QUAD

GE863-PY

1vv0300715 Rev. 1 - 19/09/06

4.2General Design Rules

The principal guidelines for the Power Supply Design embrace three different design steps:

-the electrical design

-the thermal design.

-the PCB layout.

4.2.1Electrical design Guidelines

The electrical design of the power supply depends strongly from the power source where this power is drained. We will distinguish them into three categories:

•+5V input (typically PC internal regulator output)

•+12V input (typically automotive)

•Battery

4.2.1.1 + 5V input Source Power Supply Design Guidelines

•The desired output for the power supply is 3.8V, hence there's not a big difference between the input source and the desired output and a linear regulator can be used. A switching power supply will not be suited because of the low drop out requirements.

•When using a linear regulator, a proper heat sink shall be provided in order to dissipate the power generated.

•A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks close to the GE863-QUAD/PY, a 100μF tantalum capacitor is usually suited.

•Make sure the low ESR capacitor on the power supply output (usually a tantalum one) is rated at least 10V.

•A protection diode should be inserted close to the power input, in order to save the GE863- QUAD/PY from power polarity inversion.

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Contents GE863-QUAD GE863-PY Hardware User Guide Contents 10.1 10.210.3 10.413.1 12.113.2 This document is relating to the following products Overview GE863 module connections PIN-OUTPin Signal Function Internal Type Pull up Pin Signal Function Internal Type Pins Layout Hardware Commands Turning on the GE863-QUAD/PYTurning OFF the GE863-QUAD/PY Turning off of the device can be done in two waysHardware Unconditional Reboot Hardware shutdownGE863-QUAD 1Power Supply Requirements Power SupplyGE863-QUAD/PY power requirements are 2General Design Rules Electrical design Guidelines1.2 + 12V input Source Power Supply Design Guidelines An example of linear regulator with 5V input isBattery Source Power Supply Design Guidelines An example of switching regulator with 12V input isBattery Charge control Circuitry Design Guidelines Thermal Design Guidelines Power Supply PCB layout Guidelines Antenna GSM Antenna RequirementsSerial Ports GSM Antenna installation GuidelinesGSM Antenna PCB line Guidelines Absolute Maximum Ratings -Not Functional Parameter Min Max Level Min MaxSignals in the Uart connector on the EVK are Number Pad Number17-28-36 Ground 45-48-50-56 Clear to Send Output from the GE863-QUAD/PY that2MODEM Serial Port 2 Python Debug It is available on the following pins3RS232 level translation An example of level translation circuitry of this kind is 5V Uart level translation GE863-QUAD Audio Section Overview GM863-GPS Microphone Paths Characteristic and Requirements Echo canceller type HandsetEcho canceller type Car kit hands-free + 20dBThat means You can set GA= +20dB to use standard resistor valuesTIP environment consideration General Design Rules Other considerationsMicrophone Biasing Balanced Microphone BiasingUnbalanced Microphone Biasing GE863-QUAD Buffered Balanced Mic Microphone BufferingSample circuit can be Gain = RR604605 = RR607606 Buffer gain is given by the formulaBuffered Unbalanced Single Ended Microphone Freq . = 2π * R719* C726 2π * R711* C727 Buffer bandwidth at -3dB shall be 4KHzGE863-QUAD Output Lines Speaker Short descriptionOutput Lines Characteristics SW volume level step Number of SW volume stepsNoise Filtering Handset Earphone Design Hands-Free Earphone Low Power Design An example of internal Ear amplifier could beCar Kit Speakerphone Design Evaluation Kit for Telit Modules EVK2 Short Description2 EVK2 Audio Lines Characteristics @ 350mWData Integrity ESDSchematic SIM SupplyLayout Using a Gpio Pad as Output Using a Gpio Pad as InputGeneral Purpose I/O 10.3Using the Alarm Output GPIO6 Using the Buzzer Output GPIO7DAC and ADC section 11.1DAC ConverterDescription Min Max UnitsAn AT command is available to use the DAC function Command is AT#DAC=enable,valueEnabling DAC Low Pass Filter ExampleInput Voltage range AD conversion Bits Resolution Using ADC Converter11.2ADC Converter Camera 12.1Transchip CameraType Sensitivity LuxCamera Interface Connectors Camera Physical Detail & Connector Camera Socket Connector Camera Board Module Main Block Diagram for supported cameras Schematic Diagrams for supported camera Example usage script for camera Camera setting shown here are the defaults onesTaking an reading a photo Mounting the GE863-QUAD / PY on the Application Board 13.2Module Finishing & Dimensions13.1General Surface finishing Ni/Au for all test pads Lead-free AlloyRecommended foot print for the application Stencil Debug of the GE863 in ProductionPCB pad Design Solder paste 13.2.6 GE863-QUAD / PY Solder Reflow Following is the recommended solder reflow profileGE863-QUAD Packing System Section A-AModules orientation on tray Moisture Sensibility Conformity Assessment Issues Safety Recommandations Document Change Log Revision Date Changes21/02/06 19/09/06