User's Manual
Table Of Contents
- 1 Overview
- 2 GE864-QUAD V2 Mechanical Dimensions
- 3 GE864-QUAD V2 module connections
- 4 Hardware Commands
- 5 Power Supply
- 6 Antenna
- 7 Logic level specifications
- 8 Serial Ports
- 9 Audio Section Overview
- 10 General Purpose I/O
- 10.1 GPIO Logic levels
- 10.2 Using a GPIO Pad as INPUT
- 10.3 Using a GPIO Pad as OUTPUT
- 10.4 Using the RF Transmission Control GPIO4
- 10.5 Using the RFTXMON Output GPIO5
- 10.6 Using the Alarm Output GPIO6
- 10.7 Using the Buzzer Output GPIO7
- 10.8 Indication of network service availability
- 10.9 RTC Bypass out
- 10.10 External SIM Holder Implementation
- 11 DAC and ADC section
- 12 Conformity Assessment Issues
- 14 Document Change Log
GE864-QUAD V2 Hardware User Guide
1vv0300841 Rev.0.1 24/11/09
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 23 of 65
An example of linear regulator with 5V input is:
5.3.1.2 + 12V input Source Power Supply Design Guidelines
• The desired output for the power supply is 3.8V, hence due to the big difference between the input
source and the desired output, a linear regulator is not suited and shall not be used. A switching
power supply will be preferable because of its better efficiency especially with the 2A peak current
load represented by the GE864-QUAD V2.
• When using a switching regulator, a 500kHz or more switching frequency regulator is preferable
because of its smaller inductor size and its faster transient response. This allows the regulator to
respond quickly to the current peaks absorption.
• In any case the frequency and Switching design selection is related to the application to be
developed due to the fact the switching frequency could also generate EMC interferences.
• For car PB battery the input voltage can rise up to 15,8V and this should be kept in mind when
choosing components: all components in the power supply must withstand this voltage.
• A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current
absorption peaks, 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.
• For Car applications a spike protection diode should be inserted close to the power input, in order
to clean the supply from spikes.
• A protection diode should be inserted close to the power input, in order to save the GE864-QUAD
V2 from power polarity inversion. This can be the same diode as for spike protection.