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Electrical Characteristics
MPC560xS Microcontroller Data Sheet, Rev. 2
Preliminary—Subject to Change Without Notice
Freescale Semiconductor
47
3.6
Electromagnetic compatibility (EMC) characteristics
Susceptibility tests are performed on a sample basis during product characterization.
3.6.1
EMC requirements on board
The following practices help minimize noise in applications.
A 10
μF capacitor should be placed between each of the three VDD12/VSS12 supply pairs and also between the
VDDPLL/VSSPLL pair.
VDDR should have a 220
μF capacitor. Also, VDDR should be isolated with ballast emitter to avoid voltage droop
during standby mode exit.
PAD slew rate enabled as much as possible to eliminate I/O noise
PLL modulation enabled for system clock.
Decoupling capacitors for all HV supplies to be placed close to the pins.
3.6.2
Designing hardened software to avoid noise problems
EMC characterization and optimization are performed at component level with a typical application environment and simplified
MCU software. It should be noted that good EMC performance is highly dependent on the user application and the software in
particular.
Therefore it is recommended that the user apply EMC software optimization and prequalification tests in relation with the EMC
level requested for his application.
Software recommendations
The software flowchart must include the management of runaway conditions such as:
— Corrupted program counter
— Unexpected reset
— Critical data corruption (control registers...)
Prequalification trials
Most of the common failures (unexpected reset and program counter corruption) can be
reproduced by manually forcing a low state on the reset pin or the oscillator pins for 1 second.
To complete these trials, ESD stress can be applied directly on the device. When unexpected behavior is detected, the
software can be hardened to prevent unrecoverable errors occurring.
3.6.3
Electromagnetic interference (EMI)
Table 15. EMI Testing Specifications1
Symbol
C
Parameter
Conditions
Value
Unit
Min
Typ Max
—
SR T Scan range
TBD TBD TBD MHz
—
SR T Operating frequency
TBD TBD TBD MHz