Integration Guide

Hardware Integration Guide
Specifications subject to change 16 4118723
It is recommended to use stripline design if the RF path is fairly long (more than
3cm), since microstrip design is not shielded. Consequently, the RF (transmit)
signal may interfere with neighboring electronic circuits. In the same way, the
neighboring electronics (micro-controllers, etc.) may interfere with the RF
(receive) signal and degrade the reception performance.
USB Interface
When the USB interface is externally accessible, ESD protection is required on
the USB_VBUS, USB_D+, and USB_D- signals.
Thermal Considerations
When transmitting, the AirPrime WP8548 can generate significant amounts of
heat (due to the internal Power Amplifier) that must be dissipated in the host
device for safety and performance reasons.
The amount of thermal dissipation required depends on the following factors:
• Supply voltage — Maximum power dissipation for these modules can be up to
3
W at voltage supply limits.
• Usage — Typical power dissipation values depend on the location within the
host, amount of data transferred, etc.
To enhance heat dissipation:
• Maximize airflow over / around the module
• Locate the module away from other components that generate heat
• Ensure the module is connected to a solid ground plane
EMC and ESD Recommendations
EMC tests must be performed on the application as soon as possible to detect
any potential problems.
When designing, special attention should be paid to:
• Possible spurious emissions radiated by the application to the RF receiver in
the receiver band
• ESD protection — Typically, ESD protection is mandatory for externally acces-
sible signals, including:
· VBAT_RF / VBAT_BB
· UIM (if accessible from outside)
· Serial link
· USB
· Antennas
• Length of the UIM interface lines (preferably <10 cm)
• Length of the HSIC interface lines (<10 cm, as required by the HSIC specifi-
cation)
• EMC protection on audio input/output (filters against 900 MHz emissions)