MCP2021/2/1P/2P
LIN Transceiver with Voltage Regulator
Features
• The MCP2021/2/1P/2P are compliant with LIN
Bus Specifications 1.3, 2.0, and 2.1 and are
compliant to SAE J2602
• Support Baud Rates up to 20 Kbaud with
LIN-compatible output driver
• 43V Load dump protected
• Very low EMI meets stringent OEM requirements
• Wide supply voltage, 6.0V - 18.0V continuous:
- Maximum input voltage of 30V
• Extended Temperature Range: -40 to +125°C
• Interface to PIC EUSART and standard USARTs
• Local Interconnect Network (LIN) bus pin:
- Internal pull-up resistor and diode
- Protected against ground shorts
- Protected against loss of ground
- High current drive
• Automatic thermal shutdown
• On-Chip Voltage Regulator:
- Output voltage of 5.0V with tolerances of
±3% overtemperature range
- Available with alternate output voltage of
3.3V with tolerances of ±3% overtemperature
range
- Maximum continuous input voltage of 30V
- Internal thermal overload protection
- Internal short circuit current limit
- External components limited to filter capacitor
only and load capacitor
• Two low-power modes:
- Receiver on, Transmitter off, voltage
regulator on (
≅
85 µA)
- Receiver monitoring bus, Transmitter off,
voltage regulator off (
≅
16 µA)
Description
The MCP2021/2/1P/2P provides a bidirectional, half-
duplex communication physical interface to automotive
and industrial LIN systems that meets the LIN bus
specification Revision 2.0. The devices incorporate a
voltage regulator with 5V at 50 mA or 3.3V at 50 mA
regulated power-supply outputs.
The regulator is short-circuit protected, and is protected
by an internal thermal shutdown circuit. The device has
been specifically designed to operate in the automotive
operating environment and will survive all specified
transient conditions while meeting all of the stringent
quiescent current requirements.
The MCP2021/2/1P/2P family of devices includes the
following packages.
8-pin PDIP, DFN and SOIC packages:
• MCP2021-330, LIN-compatible driver, 8-pin, 3.3V
regulator, wake up on dominant level of LBUS
• MCP2021-500, LIN-compatible driver, 8-pin, 5.0V
regulator, wake up on dominant level of LBUS
• MCP2021P-330, LIN-compatible driver, 8-pin,
3.3V regulator, wake up at falling edge of LBUS
voltage
• MCP2021P-500, LIN-compatible driver, 8-pin,
5.0V regulator, wake up at falling edge of LBUS
voltage
14-pin PDIP, TSSOP and SOIC packages with RESET
output:
• MCP2022-330, LIN-compatible driver, 14-pin,
3.3V regulator, RESET output, wake up on domi-
nant level of LBUS
• MCP2022-500, LIN-compatible driver, 14-pin,
5.0V regulator, RESET output, wake up on domi-
nant level of LBUS
• MCP2022P-330, LIN-compatible driver, 14-pin,
3.3V regulator, RESET output, wake up at falling
edge of LBUS voltage
• MCP2022P-500, LIN-compatible driver, 14-pin,
5.0V regulator, RESET output, wake up at falling
edge of LBUS voltage
©
2005-2012 Microchip Technology Inc.
DS22018F-page 1
MCP2021/2/1P/2P
1.0
DEVICE OVERVIEW
EQUATION 1-1:
R
TP
<= (V
BBmin
- 5.5) / 250 mA.
5.5V = V
UVLO
+ 1.0V,
250 mA is the peak current at Power-On when
V
BB
= 5.5V
The MCP2021/2/1P/2P provides a physical interface
between a microcontroller and a LIN half-duplex bus. It
is intended for automotive and industrial applications
with serial bus speeds up to 20 Kbaud.
The MCP2021/2/1P/2P provides a half-duplex, bidirec-
tional communications interface between a microcon-
troller and the serial network bus. This device will
translate the CMOS/TTL logic levels to LIN-level logic,
and vice versa.
The LIN specification 2.0 requires that the trans-
ceiver(s) of all nodes in the system be connected via
the LIN pin, referenced to ground, and with a maximum
external termination resistance load of 510Ω from LIN
bus to battery supply. The 510Ω corresponds to 1 Mas-
ter and 16 Slave nodes.
The MCP2021/2/1P/2P-500 provides a +5V, 50 mA,
regulated power output. The regulator uses an LDO
design, is short-circuit protected, and will turn the
regulator output off if it falls below 3.5V.
The MCP2021/2/1P/2P
shutdown protection.
also
includes
thermal-
1.2
1.2.1
Internal Protection
ESD PROTECTION
For component-level ESD ratings, please refer to the
Section 2.1 “Absolute Maximum Ratings†”.
1.2.2
GROUND LOSS PROTECTION
The LIN Bus specification states that the LIN pin must
transition to the recessive state when ground is discon-
nected. Therefore, a loss of ground effectively forces
the LIN line to a hi-impedance level.
1.2.3
THERMAL PROTECTION
The thermal protection circuit monitors the die temper-
ature and is able to shut down the LIN transmitter and
voltage regulator if it detects a thermal overload.
There are three causes for a thermal overload. A ther-
mal shut down can be triggered by any one, or a com-
bination of, the following thermal overload conditions:
• Voltage regulator overload
• LIN bus output overload
• Increase in die temperature due to increase in
environmental temperature
Driving the TXD and checking the RXD pin makes it
possible to determine whether there is a bus contention
(i.e., Rx = low, Tx = high) or a thermal overload condi-
tion (i.e., Rx = high, Tx = low).
The regulator is specifically designed to operate in the
automotive environment and will survive +43V load
dump transients, double-battery jumps, and reverse
battery connections when a reverse blocking diode is
used. The other members of the MCP2021/2/1P/2P-
330 family output +3.3V at 50 mA with a turn-off voltage
of 2.5V. (See
Section 1.6 “Internal Voltage
Regulator”).
MCP2021/2 wakes from Power-Down mode on a
dominant level on LBUS. MCP2021P/2P wakes at a
transition from recessive level to dominant level on
LBUS.
1.1
1.1.1
Optional External Protection
REVERSE BATTERY PROTECTION
An external reverse-battery-blocking diode should be
used to provide polarity protection (see
Figure 1-6).
1.1.2
TRANSIENT VOLTAGE
PROTECTION (LOAD DUMP)
An external 43V transient suppressor (TVS) diode,
between V
BB
and ground, with a 50Ω transient protec-
tion resistor (R
TP
) in series with the battery supply and
the V
BB
pin protect the device from power transients
(see
Figure 1-6)
and ESD events. While this protection
is optional, it is considered good engineering practice.
The resistor value is chosen according to
Equation 1-1.
©
2005-2012 Microchip Technology Inc.
DS22018F-page 5
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