MC33388DR2 Freescale Semiconductor, MC33388DR2 Datasheet - Page 8

• Manufacturer Part Number: MC33388DR2
• Description: IC TOLERANT CAN INT FAULT 14SOIC
• Manufacturer: Freescale Semiconductor

Specifications of MC33388DR2

• Controller Type: CAN Interface
• Interface: CAN
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 5mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: Q1163428C

setting power on flag” threshold, this information is internally
latched. This means that the system power supply has been
lost (disconnected and reconnected for instance).
the device into receive only mode, where NERR pin reports
the VBAT power on flag. This flag is reset by entering into the
Normal mode.
detects faults in normal and receive only modes. Below is the
list of failures detected at the bus level:
TX Permanent Dominant Detection
permanent low state at TX input which results of a permanent
dominant bus state. The MC33388 detects if TX is Low for
more than 2ms typical and then disables the bus output driver
in order to switch into recessive state. This avoid to block
communication between other nodes of the network.
Behaviour Under Faults Condition
appropriate
consumption and to allow communication on the network.
Depending on the type of fault, the mode of operation and the
fault detected, the device automatically switches off one or
more of the following functions: CANL or CANH line driver, Rtl
or Rth pull up or down resistors or internal switches. These
actions are detailed in table 2.
fault recovery, it automatically switches back to normal
operation and reconnects the open functions. Faults detection
and recovery circuitry have internal filters and delays timing
detailed in the AC characteristics parameters section.
Detailed Description of Error Detections
assures a proper reception in the normal operating modes
and in case of failures 1, 2 and 5 noise margin as high as
possible. These failures or their recovery do not destroy
ongoing transmissions.
MC33388
Battery Fail Flag
Bus Failure Detection
When the VBAT supply drops below “battery voltage for
This flag can be read by the microcontroller by switching
The device permanently monitors the bus lines and
1- CANH wire interruption
2- CANL wire interruption
3- CANH short-circuit to battery
4- CANL short-circuit to ground
5- CANH short-circuit to ground
6- CANL short-circuit to battery
7- CANL and CAN H mutually shorted
8- CANH short-circuit to Vdd
In addition to the above list, the MC33388 detects a
When a fault is detected, the device automatically takes
The device permanently monitors the faults and in case of
The differential receiver threshold is set at -2,8V. This
action
to
Archived by Freescale Semiconductor, Inc., 2008
minimize
the
system
DEVICE DESCRIPTION
current
MOTOROLA
connected to CANH and CANL. If the comparator threshold is
exceeded for a certain time, the device is switched to single
wire mode. This time is needed to avoid false triggering by
external RF fields. Recovery from these failures is detected
automatically after a certain time-out (filtering) and no
transmission is lost.
level at the internal comparator outputs. If failure 4 and 7
appear, the CANL driver and the RTL pin are switched off after
a time out, only a weak pull up at RTL remains. Reception
continues by switching to single wire mode through CANH.
When the failures 4 or 7 are removed, the recessive bus levels
are restored. If the receiver voltages remain in the recessive
state for a certain time, reception and transmission switch
back to the differential mode.
after a time out and the reception is switched to single wire
mode through CANL. If the receiver voltages remain in the
recessive state for a certain time, reception and transmission
switch back automatically to the differential mode.
be switched low. When the error recovers, NERR will be
switched back to high state.
Wake Up Events
Sleep or VBAT Stanby modes, either when a dominant state is
detected on CANL or CANH bus lines (remote wake-up) or if
the WAKE pin changes state (local wake-up).
the state voltage on the WAKE pin is considered to be the
reference state for the wake-up function. On leaving normal
mode, the current WAKE pin state becomes the new
reference state.
the INH output high, to activate the external voltage regulator,
used for VDD supplied. In VBAT standby INH is already set
high. When VDD is set, the wake-up request can be read on
the NERR or RX outputs by the microcontroller.
wake-up threshold levels have to be maintained for a certain
time. In the low power modes, failure detection circuit remains
partly active to prevent increased power consumption in
cases of error 3, 4, 7 and 8.
Fault Operation Table
power modes and the internal actions happening under fault
condition. Please refer to simplified block diagram page 1 for
device internal switch reference.
Failures 3 and 6 are detected by comparators respectively
Failures 4, 7 and 8 initially result in a permanent dominant
If failure 8 is recognized, the CANH driver is switched off
If any of the 8 wiring failure occurs, the output NERR will
Wake-up requests are recognized by the MC33388 in
Under power-up conditions when VBAT is higher than 5V,
In sleep mode, on a wake-up request the transceiver sets
To prevent false wake-up due to transients or RF fields,
Table 2 shows the device operation in normal and low
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