1.0 DEVICE OVERVIEW
The MCP2003/4/3A/4A devices provide a physical
interface between a microcontroller and a LIN bus.
These devices will translate the CMOS/TTL logic levels
to LIN logic level, and vice versa. It is intended for
automotive and industrial applications with serial bus
speeds up to 20 kbaud.
LIN Bus Specification Revision 2.1 requires that the
transceiver of all nodes in the system is connected via
the LIN pin, referenced to ground and with a maximum
external termination resistance load of 510 from LIN
bus to battery supply. The 510 corresponds to
1 master and 15 slave nodes.
The VREN pin can be used to drive the logic input of an
external voltage regulator. This pin is high in all modes
except for Power-Down mode.
1.1 External Protection
1.1.1 REVERSE BATTERY PROTECTION
An external reverse-battery-blocking diode should be
used to provide polarity protection (see Example 1-1).
PROTECTION (LOAD DUMP)
An external 43V transient suppressor (TVS) diode,
between VBB and ground, with a 50 transient
protection resistor (RTP) in series with the battery
supply and the VBB pin serve to protect the device from
power transients (see Example 1-1) and ESD events.
While this protection is optional, it is considered good
1.2 Internal Protection
1.2.1 ESD PROTECTION
For component-level ESD ratings, please refer to the
maximum operation specifications.
1.2.2 GROUND LOSS PROTECTION
The LIN Bus specification states that the LIN pin must
transition to the recessive state when ground is
disconnected. Therefore, a loss of ground effectively
forces the LIN line to a high-impedance level.
1.2.3 THERMAL PROTECTION
The thermal protection circuit monitors the die
temperature and is able to shut down the LIN
There are two causes for a thermal overload. A thermal
shutdown can be triggered by either, or both, of the
following thermal overload conditions.
• LIN bus output overload
• Increase in die temperature due to increase in
Driving the TXD and checking the RXD pin makes it
possible to determine whether there is a bus contention
(Rx = low, Tx = high) or a thermal overload condition
(Rx = high, Tx = low). After a thermal overload event,
the device will automatically recover once the die
temperature has fallen below the recovery temperature
threshold (see Figure 1-1).
Shorted LIN bus
Temp < ShutdownTEMP
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