Telit Wireless Solutions GE864 manual Power Supply PCB layout Guidelines

Page 27

GE864 Hardware User Guide

1vv0300694 Rev.10 - 10/06/08

5.2.3 Power Supply PCB layout Guidelines

As seen on the electrical design guidelines the power supply shall have a low ESR capacitor on the output to cut the current peaks and a protection diode on the input to protect the supply from spikes and polarity inversion. The placement of these components is crucial for the correct working of the circuitry. A misplaced component can be useless or can even decrease the power supply performances.

•The Bypass low ESR capacitor must be placed close to the Telit GE864-QUAD / PY power input pads or in the case the power supply is a switching type it can be placed close to the inductor to cut the ripple provided the PCB trace from the capacitor to the GE864-QUAD / PY is wide enough to ensure a dropless connection even during the 2A current peaks.

•The protection diode must be placed close to the input connector where the power source is drained.

•The PCB traces from the input connector to the power regulator IC must be wide enough to ensure no voltage drops occur when the 2A current peaks are absorbed. Note that this is not made in order to save power loss but especially to avoid the voltage drops on the power line at the current peaks frequency of 216 Hz that will reflect on all the components connected to that supply, introducing the noise floor at the burst base frequency. For this reason while a voltage drop of 300- 400 mV may be acceptable from the power loss point of view, the same voltage drop may not be acceptable from the noise point of view. If your application doesn’t have audio interface but only uses the data feature of the Telit GE864-QUAD / PY, then this noise is not so disturbing and power supply layout design can be more forgiving.

•The PCB traces to the GE864-QUAD / PY and the Bypass capacitor must be wide enough to ensure no significant voltage drops occur when the 2A current peaks are absorbed. This is for the same reason as previous point. Try to keep this trace as short as possible.

•The PCB traces connecting the Switching output to the inductor and the switching diode must be kept as short as possible by placing the inductor and the diode very close to the power switching IC (only for switching power supply). This is done in order to reduce the radiated field (noise) at the switching frequency (100-500 kHz usually).

•The use of a good common ground plane is suggested.

•The placement of the power supply on the board should be done in such a way to guarantee that the high current return paths in the ground plane are not overlapped to any noise sensitive circuitry as the microphone amplifier/buffer or earphone amplifier.

•The power supply input cables should be kept separate from noise sensitive lines such as microphone/earphone cables.

Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved

page 27 of 69

Page 26 Page 28
Image 27
Page 26 Page 28
Contents GE864 Hardware User Guide This document is relating to the following products GE864 Hardware User GuideContents 10.4 10.110.2 10.3Packing system Safety RecommandationsDisclaimer GE864-QUAD / PY OverviewLength 30 mm Width Thickness GE864 Mechanical DimensionsPIN-OUT GE864 module connectionsGpio Reserved Vbatt TOP View BGA Balls LayoutReserved Turning on the GE864-QUAD / PY Hardware Commands10k Turning OFF the GE864-QUAD / PY Hardware shutdownHardware Unconditional Restart 10k Power Supply Requirements Power SupplyElectrical Design Guidelines General Design Rules1.2 + 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 GSM Antenna Requirements AntennaAntenna Line on PCB Requirements GSM Antenna PCB line GuidelinesGSM Antenna Installation Guidelines Operating Range Interface levels 2.8V Cmos Logic level specificationsCurrent characteristics Absolute Maximum Ratings -Not FunctionalReset signal Signal Function Bga BallSignal Min Max Serial Ports Absolute Maximum Ratings -Not Functional ParameterMin MaxOperating Range Interface levels 2.8V Cmos Level Min Max Signals of the GE864 serial port are RS232 level translation GE864 Hardware User Guide 5V Uart level translation GE864 Hardware User Guide External Amplifier Audio Section OverviewShort description Input Lines MicrophoneMicmt 1st differential microphone path Input Lines CharacteristicsOutput Lines Speaker External SIM Holder Implementation Output Lines CharacteristicsOnoff General Purpose I/OPict01 Gpio Logic levels Absolute Maximum Ratings -Not Functional Parameter Min MaxOperating Range Interface levels 1.8V Cmos Level Min Max Using a Gpio Pad as Output Using a Gpio Pad as InputUsing the RF Transmission Control GPIO4 Using the Rftxmon Output GPIO5Using the Alarm Output GPIO6 AT#SRP=3 Using the Buzzer Output GPIO7Magnetic Buzzer Concepts Power Supply Influence Frequency BehaviourWorking Current Influence Allowed Gpio Using the Temperature Monitor FunctionLED status Device Status Indication of network service availabilityRTC Bypass out VAUX1 power outputMin Max Units DAC and ADC sectionDAC Converter DescriptionCommand is AT#DAC=enable,value Enabling DACLow Pass Filter Example ADC Converter Using ADC ConverterModule finishing & dimensions Mounting the GE864 on your Board12.1General Top View Recommended foot print for the application GE864Top View Suggested Inhibit AreaStencil Debug of the GE864 in productionPCB pad design Ball pitch mm Solder resist opening diameter a mmMetal pad diameter B mm Solder paste Sn/Ag/Cu Solder pasteFinish Layer thickness µm Properties Lead freeFollowing is the recommended solder reflow profile 12.1.8 GE864 Solder reflowPacking system 12.2.1 GE864 orientation on the tray Moisture sensibility Conformity Assessment Issues Safety Recommandations Revision Date Changes Document Change Log

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.
Top Page Image Contents