User's Manual

SARA-G3 and SARA-U2 series - System Integration Manual
The application device integrating a SARA-G350 ATEX or a SARA-U270 ATEX module for use in potentially
explosive atmospheres must be designed so that any circuit/part of the apparatus shall not invalidate the specific
characteristics of the type of protection of the module.
The intrinsic safety ‘i’ type of protection of SARA-G350 ATEX and SARA-U270 ATEX modules is based on the
restriction of electrical energy within equipment and of interconnecting wiring exposed to the explosive
atmosphere to a level below that which can cause ignition by either sparking or heating effects.
The following input and equivalent parameters must be considered integrating a SARA-G350 ATEX module or a
SARA-U270 ATEX module in an application device intended for use in potentially explosive atmospheres:
• Total internal capacitance, Ci
• Total internal inductance, Li
• The module does not contain blocks which increase the voltage (e.g. like step-up, duplicators, boosters, etc.)
The nameplate of SARA-G350 ATEX and SARA-U270 ATEX modules is described in the ‘Product labeling’ section
of the SARA-G3 series Data Sheet [1] and SARA-U2 series Data Sheet [2]. Additional information can be found
on the SARA-G350 ATEX and SARA-U270 ATEX modules’ certificate of compliancy for use in potentially
explosive atmospheres available on our website (
www.u-blox.com).
The final enclosure of the application device integrating SARA-G350 ATEX or SARA-U270 ATEX modules,
intended for use in potentially explosive atmospheres, must guarantee a minimum degree of ingress
protection of IP20.
2.14.2 Guidelines for VCC supply circuit design
The power supply ratings, average and pulse, must be considered in the design of the VCC supply circuit on the
application device integrating SARA-G350 ATEX module or SARA-U270 ATEX module, implementing proper
circuits providing adequate maximum voltage and current to the VCC supply input of the modules, according to
the specific potentially explosive gas atmosphere category subdivision where the apparatus is intended for use.
Table 58 lists the maximum input and equivalent parameters that must be considered in sub-division IIC for
SARA-G350 ATEX and SARA-U270 ATEX.
Parameter SARA-G350 ATEX SARA-U270 ATEX
Ui 3.8 V 3.8 V
Ii 1.6 A (burst) 1.6 A (burst)
Pi 2.5 W TBD W
Ci 103 µF 132 µF
Li 4.1 µH 9.8 µH
Table 58: Maximum input and equivalent parameters for sub-division IIC
Table 59 lists the maximum input and equivalent parameters that must be considered in sub-division IIB and IIA
for SARA-G350 ATEX and SARA-U270 ATEX.
Parameter SARA-G350 ATEX SARA-U270 ATEX
Ui 4.2 V 4.2 V
Ii 2.5 A (burst) 2.5 A (burst)
Pi 2.5 W TBD W
Ci 103 µF 132 µF
Li 4.1 µH 9.8 µH
Table 59: Maximum input and equivalent parameters for sub-division IIB and IIA
UBX-13000995 - R12 Early Production Information Design-in
Page 153 of 196