User Manual
Table Of Contents
- Document History
- Introduction
- Product Concept
- GSM Application Interface
- GSM/GPRS Operating Modes
- Power Supply
- Power Up / Down Scenarios
- Automatic GPRS Multislot Class Change
- Charging Control of the GSM Part
- Power Saving
- Summary of State Transitions (Except SLEEP Mode)
- RTC Backup for GSM Part of XT55/56
- Serial Interfaces of the XT55/56 GSM Part
- Audio Interfaces
- SIM Interface
- Control Signals
- GPS Application Interface
- GSM and GPS Antenna Interfaces
- Electrical, Reliability and Radio Characteristics
- Mechanics
- Reference Approval
- Example Applications
- List of Parts and Accessories
XT55/56 Hardware Interface Description
Confidential / Preliminary
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XT55/56_hd_v02.96 Page 109 of 125 18.08.2005
6.7 Electrostatic Discharge
The GSM engine is not protected against Electrostatic Discharge (ESD) in general.
Consequently, it is subject to ESD handling precautions that typically apply to ESD sensitive
components. Proper ESD handling and packaging procedures must be applied throughout
the processing, handling and operation of any application that incorporates a XT55/56
module.
Special ESD protection provided on XT55/56:
Antenna interface: one spark discharge line (spark gap)
SIM interface: clamp diodes for protection against overvoltage.
The remaining ports of XT55/56 are not accessible to the user of the final product (since they
are installed within the device) and therefore, are only protected according to the “Human
Body Model” requirements.
XT55/56 has been tested according to the EN 61000-4-2 standard. The measured values
can be gathered from the following table.
Table 35: Measured electrostatic values
Specification / Requirements Contact discharge Air discharge
ETSI EN 301 489-7
ESD at SIM port (GSM)
± 4kV ± 8kV
ESD at GSM antenna port
± 4kV ± 8kV
Indirect ESD to GSM part
± 4kV
-
Indirect ESD to GPS part
± 4kV
-
Human Body Model (Test conditions: 1.5 kΩ, 100 pF)
ESD at GPS antenna port
± 1kV
ESD at all other ports
± 1kV
Please note that the values may vary with the individual application design. For example, it matters
whether or not the application platform is grounded over external devices like a computer or other
equipment, such as the Siemens reference application described in Chapter 8.