JODY-W2 - System integration manual
UBX-18068879 - R14
Design-in
Page 33 of 84
C1 - Public
For best performance, consider the following guidelines when designing the layout:
•
Vias specification for ground filling:
300/600𝜇𝑚
, no thermal reliefs are allowed on vias.
•
Ground vias density under the module:
50 𝑣𝑖𝑎𝑠/𝑐𝑚
2
, thermal vias can be placed in gaps between
module’s thermal pads.
•
Minimum layer count and copper thickness:
4 𝑙𝑎𝑦𝑒𝑟𝑠
,
35 𝜇𝑚
.
•
Minimum board size:
55𝑥70 𝑚𝑚
.
•
Power planes and signal traces should not cross the layers beneath the module to maximize heat
flow from the module.
Those recommendations allow the design to achieve a thermal characterization parameter of
ψ
𝐽𝐵
=
15.0 °𝐶/𝑊
, where
𝐽𝐵
refers to the
“module’s junction to main PCB bottom side”
.
The following additional hardware techniques can be used to improve the thermal performance of the
module in
customer’s
applications:
•
Maximize antenna
’s
return loss to reduce reflected RF power to the module.
•
Improve the efficiency and the thermal design of any component that generates heat in the
application, including power supplies and processor, to spread the generated heat distribution
over the application device.
•
Properly design the mechanical enclosure of the application device to provide ventilation and good
thermal dissipation.
•
For continuous operation at high temperatures, high power density applications or reduced PCB
size, the designer may consider a heat sink
on main PCB’s bottom
side, connected through
electrically insulated / high thermal conductivity adhesive
9
.
2.9
ESD guidelines
JODY-W2 module is manufactured through a highly automated process, which complies with
IEC61340-5-1
[6]
(STM5.2-1999 Class M1 devices) standard. A manufacturing process on
customer’s manufacturing site that im
plements a basic ESD control program is considered sufficient
to satisfy the necessary precautions
10
for handling the modules. The ESD ratings of JODY-W2
module pins are stated in the JODY-W2 series data sheet
In compliance with the following European regulations, the designer must implement proper
measures to protect from ESD events on any pin that may be exposed to the end user:
•
ESD testing standard CENELEC EN 61000-4-2
•
Radio equipment standard ETSI EN 301 489-1
[5]
The minimum requirements for conformance to these European regulations are summarized in
Application
Category
Immunity level
All exposed surfaces of the radio equipment and ancillary
equipment in a representative configuration of the end product.
Contact Discharge
4 kV
Air Discharge
8 kV
Table 22: Minimum ESD immunity requirements based on EN 61000-4-2
Compliance with standard protection level as specified in EN 61000-4-2
[5]
can be achieved by
including proper ESD protections in parallel to the line, close to areas accessible by the end user.
9
Typically not required.
10
Minimum ESD protection level for safe handling is specified in JEDEC JEP155 (HBM) and JEP157 (CDM) for ±500 V and
±250 V respectively.
