Telit Wireless Solutions GE864 manual General Design Rules, Electrical Design Guidelines

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GE864 Hardware User Guide

1vv0300694 Rev.10 - 10/06/08

The GSM system is made in a way that the RF transmission is not continuous, else it is packed into bursts at a base frequency of about 216 Hz, the relative current peaks can be as high as about 2A. Therefore the power supply has to be designed in order to withstand with these current peaks without big voltage drops; this means that both the electrical design and the board layout must be designed for this current flow.

If the layout of the PCB is not well designed a strong noise floor is generated on the ground and the supply; this will reflect on all the audio paths producing an audible annoying noise at 216 Hz; if the voltage drop during the peak current absorption is too much, then the device may even shutdown as a consequence of the supply voltage drop.

TIP: The electrical design for the Power supply should be made ensuring it will be capable of a peak current output of at least 2 A.

5.2 General Design Rules

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

•the electrical design

•the thermal design

•the PCB layout.

5.2.1 Electrical 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

5.2.1.1 + 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 GE864-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 GE864-QUAD / PY from power polarity inversion.

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Contents GE864 Hardware User Guide GE864 Hardware User Guide This document is relating to the following productsContents 10.1 10.210.3 10.4Safety Recommandations Packing systemDisclaimer Overview GE864-QUAD / PYGE864 Mechanical Dimensions Length 30 mm Width ThicknessGE864 module connections PIN-OUTGpio Reserved Vbatt BGA Balls Layout TOP ViewReserved Hardware Commands Turning on the GE864-QUAD / PY10k Hardware Unconditional Restart Turning OFF the GE864-QUAD / PYHardware shutdown 10k Power Supply Power Supply RequirementsGeneral Design Rules Electrical Design Guidelines1.2 + 12V input Source Power Supply Design Guidelines GE864 Hardware User Guide Battery Source Power Supply Design Guidelines Battery Charge control Circuitry Design Guidelines GE864 Hardware User Guide Thermal Design Guidelines Power Supply PCB layout Guidelines Antenna GSM Antenna RequirementsGSM Antenna PCB line Guidelines Antenna Line on PCB RequirementsGSM Antenna Installation Guidelines Logic level specifications Current characteristicsAbsolute Maximum Ratings -Not Functional Operating Range Interface levels 2.8V CmosSignal Min Max Reset signalSignal Function Bga Ball Operating Range Interface levels 2.8V Cmos Level Min Max Serial PortsAbsolute Maximum Ratings -Not Functional ParameterMin Max Signals of the GE864 serial port are RS232 level translation GE864 Hardware User Guide 5V Uart level translation GE864 Hardware User Guide Audio Section Overview External AmplifierInput Lines Microphone Short descriptionInput Lines Characteristics Micmt 1st differential microphone pathOutput Lines Speaker Output Lines Characteristics External SIM Holder ImplementationGeneral Purpose I/O OnoffPict01 Operating Range Interface levels 1.8V Cmos Level Min Max Gpio Logic levelsAbsolute Maximum Ratings -Not Functional Parameter Min Max Using a Gpio Pad as Input Using a Gpio Pad as OutputUsing the Alarm Output GPIO6 Using the RF Transmission Control GPIO4Using the Rftxmon Output GPIO5 Using the Buzzer Output GPIO7 AT#SRP=3Magnetic Buzzer Concepts Working Current Influence Power Supply InfluenceFrequency Behaviour Using the Temperature Monitor Function Allowed GpioIndication of network service availability LED status Device StatusVAUX1 power output RTC Bypass outDAC and ADC section DAC ConverterDescription Min Max UnitsLow Pass Filter Example Command is AT#DAC=enable,valueEnabling DAC Using ADC Converter ADC Converter12.1General Module finishing & dimensionsMounting the GE864 on your Board Recommended foot print for the application GE864 Top ViewSuggested Inhibit Area Top ViewDebug of the GE864 in production StencilMetal pad diameter B mm PCB pad designBall pitch mm Solder resist opening diameter a mm Solder paste Finish Layer thickness µm PropertiesLead free Solder paste Sn/Ag/Cu12.1.8 GE864 Solder reflow Following is the recommended solder reflow profilePacking system 12.2.1 GE864 orientation on the tray Moisture sensibility Conformity Assessment Issues Safety Recommandations Document Change Log Revision Date Changes

GE864 specifications

The Telit Wireless Solutions GE864 is a compact yet robust cellular module designed for a wide range of M2M (Machine-to-Machine) applications. As part of the Telit family, the GE864 is particularly notable for its small form factor, reliability, and versatility, making it an ideal choice for various industries including automotive, healthcare, and utilities.

One of the standout features of the GE864 is its integrated GPRS capabilities, allowing devices to connect to cellular networks seamlessly. With a maximum data rate of 85.6 kbps for downlink and 42.8 kbps for uplink, this module facilitates efficient data transmission, suitable for applications that require real-time data monitoring and control.

The GE864 supports multiple frequency bands, ensuring global compatibility. It can operate on GSM/GPRS networks, enhancing its usability across different regions. This multi-band support allows developers to deploy their solutions in diverse markets without modifying the hardware, thus saving both time and resources.

Power management is another critical area where the GE864 shines. The module comes equipped with advanced power-saving features, allowing it to operate effectively in battery-powered applications. Notable features include sleep modes and intelligent power management protocols that help extend battery life while maintaining reliable connectivity.

In terms of physical specifications, the GE864 has a compact design, measuring only 29x38 mm, which is essential for integration into space-constrained environments. This makes it particularly well-suited for applications in remote monitoring, asset tracking, and utility metering.

The module supports a range of interfaces, including UART, USB, and I2C, providing developers with the flexibility to connect various peripheral devices and sensors. This versatility enables the creation of customized solutions tailored to specific application needs.

Furthermore, the GE864 is designed to meet rigorous quality and durability standards, making it suitable for use in harsh environments. Its resilience to extreme temperatures and vibrations ensures dependable performance in challenging conditions, which is often a requirement in industrial and automotive applications.

In summary, the Telit Wireless Solutions GE864 is a feature-rich cellular module that combines compact design with robust performance and versatility. Its advanced connectivity options, efficient power management, and reliable operation make it an invaluable asset for businesses looking to develop innovative M2M solutions. Whether it’s for smart cities, telematics, or healthcare applications, the GE864 is engineered to meet the demands of today's connected world.
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