Test Interfaces; Production / After Sales Interface - Nokia RH-27 Series Technical Documentation Manual

CCS Technical Documentation
tors incorporated to reduce rise times and reflections. Slew rate controlled buffers should
be used on custom components wherever possible to reduce the EMC produced by the
circuit. Separate power supplies for digital, analog, and RF-blocks should be used as
much as possible. Baseband and RF supply power rails should be isolated from each other
by means of inductors in the power supply rail to prevent high-frequency components
produced on the baseband power supply rail to spread out over the RF power supply
plane. This might be required to avoid interference from digital circuits to affect the per-
formance of RF section.
All external connectors and connection must be filtered using RC or LC networks to pre-
vent the high frequency components from entering connection cables that then will act
as antennas. The amount of this type of EMC component is in straight relation to the
amount of external connections. The type of network and amount of components to be
used is determined by the AC and DC impedance characteristic of that particular signal.
Low-impedance signals require LC networks while medium impedance level signals
(input signals at moderate bandwidth) can use RC networks.
The EMC protection should also prevent external or internal signals to cause interference
to baseband and in particular to audio signals. Internal interference is generated by the
transmitter burst frequency and the switchmode charging. The transmitter burst fre-
quency interference is likely to cause noise to both microphone and earphone signals.
The transmitter RF interference is likely to cause more problems in the microphone cir-
cuitry than in the earphone circuitry since the earpiece is a low impedance dynamic type.
As mechanical guidelines, the baseband and RF sections should be isolated from each
other using EMC shielding, which suppresses radiated interference. The transmitter burst
frequency can also generate mechanical vibrations that can be picked up by the micro-
phone if it is not properly isolated from the chassis using rubber or some other soft
material. Connection wires to internal microphone and earphone should be as short as
possible to reduce the interference caused by internal signals.
ESD protection has to be implemented on each external connection that is accessible
during normal operation of the phone.

Test Interfaces

Using the Tomahawk connector FBUS connections, the phone HW can be tested by PC
software (i.e., Phoenix test software). In addition, RH-27 will also support Flash program-
ming interface via the service battery, JTAG, and Ostrich test interfaces. JTAG test inter-
face may be removed from the final product for security reasons.

Production / After Sales Interface

Test pads are placed on engine PWB, for service and production purposes. Same test pat-
tern is used by the After Market Sales (AMS) group for product testing and software
upgrades. The following figure shows the top view of the test pads. FBUS_TX and RX
lines are used to transfer data in or out of the phone. VPP is the Flash programming volt-
age and MBUS/CLK line is used as Flash clock line during flashing of phone.
Issue 1 11/2003
© 2003 Nokia Corporation
System Module
Confidential
RH-27
Page 23