Specifications
Rev 2.0 Apr.10 Proprietary and Confidential 67
7
7: Design Checklist
This chapter provides a summary of the design considerations
mentioned throughout this guide. This includes items relating to the
power interface, RF integration, thermal considerations, cabling
issues, and so on.
Note: This is NOT an exhaustive list of design considerations. It is expected
that you will employ good design practices and engineering principles in your
integration.
Table 7-1: Hardware integration design considerations
Suggestion Section where discussed
Component placement
Protect the USIM socket so the USIM cannot be removed while
the host is powered up.
USIM operation on page 61
If an ESD suppressor is not used, allow space on the USIM
connector for series resistors in layout. (Up to 100 may be
used depending on ESD testing requirements).
USIM operation on page 61
Minimize RF cable losses as these affect performance values
listed in product specification documents.
RF connection on page 39
Antennas
Match the module/antenna coax connections to 50 —
mismatched antenna impedance and cable loss negatively
affect RF performance.
RF connection on page 39
If installing both the MC57xx and MC8xxx in the same device,
consider using separate antennas for maximum performance.
Antenna and cabling on
page 40
Power
Limit host power rail dips caused by module inrush current by
adding sufficient capacitance to the host power rail.
Inrush currents on page 24
Make sure the power supply can handle the maximum current
specified for the module type.
Current consumption overview
on page 27
Limit the total impedance of VCC and GND connections to the
USIM at the connector to less than 1 (including any trace
impedance and lumped element components—inductors, filters,
etc.). All other lines must have a trace impedance less than 2 .
USIM operation on page 61
Decouple the VCC line close to the USIM socket. The longer the
trace length (impedance) from socket to module, the greater the
capacitance requirement to meet compliance tests.
USIM operation on page 61