MC33989PEG Freescale Semiconductor, MC33989PEG Datasheet - Page 54

• Manufacturer Part Number: MC33989PEG
• Description: SBC-HS
• Manufacturer: Freescale Semiconductor

TYPICAL APPLICATIONS
SUPPLEMENTAL APPLICATION NOTES
CAN Driver Over-temperature:
bit set in the CAN register. If enabled, an interrupt will be signalled. The GFAIL flag is set in the MCR register.
below the over-temperature level minus hysteresis, the CAN driver is automatically re-enabled.
Overcurrent Detection:
is signalled by the bit CUR in the CAN register. An INT can be enabled, and GFAIL bit is set. The CUR bit is latched and two
conditions are necessary to clear it:
Protection
ISO7637 Transient
situations like the bus directly shorted to the battery line in a load dump situation (+40 V).
network will not be affected. However the CANH and CANL lines of the ungrounded module will see a negative voltage of the
VBAT value, with respect to their gnd level. Such situations can be handled by the CAN interface of the MC33989, but also in
cases of a jump start (battery at 27 V) and gnd disconnection.
Vdc must be respected.
ESD
zener diode suppressor can be added to ensure a higher module resistance to ESD.
Current in Case of Bus Short Conditions
case. The
54
33989
In case of an over-temperature condition at the CANH or CANL driver, the driver will be automatically disabled and the THERM
When the CAN is in an over-temperature situation, the device is no longer able to transmit. As soon as the temperature is
The THERM bit is latched and two conditions are necessary to clear it:
• No longer “CAN over-temperature situation” AND
• Read operation of the CAN register.
The CAN interface can detect and signal over-current condition, occurring for instance in case of CANL shorted to VBAT. This
• No longer “CAN over-current situation” AND
• Read operation of the CAN register.
The MC33989 CAN output is protected for automotive environments.
The CAN driver is protected against over-temperature and over-current.
The CANH and CANL are rated from +40 Vdc to -27 Vdc. This means that the MC33989 CAN output can handle failure
Ground disconnection of the module will lead to the CANH and CANL line floating high to the VBAT supply. The rest of the
Fast transient pulses, ISO7637-3. During these pulses, the maximum rating of the CANH and CANL lines of +40 Vdc and -27
The CANH and CANL line of the MC33989 are rated at ±4.0 kV. An external capacitor between CANH and CANL to gnd or a
In case of short-circuit condition on the CAN bus the current in the CAN supply, the CAN line can be different from the nominal
Figure 44
and
Table 35
describe the various cases.
Figure 44. Current in Case of Bus Short Conditions
V2 Terminal
CANL
CANH
60 ohms
I_TERM
I_H
I_L
CAN L line
CANH line
VBAT
5V
VBAT
5V
Analog Integrated Circuit Device Data
Freescale Semiconductor