MCP201
LIN Transceiver with Voltage Regulator
Features
• Supports baud rates up to 20 Kbaud
• 40V load dump protected
• Wide supply voltage, 6.0 – 18.0V, continuous
- Maximum input voltage of 30V
• Extended Temperature Range: -40°C to +125°C
• Interface to standard USARTs
• Compatible with LIN Spec 1.3
• Local Interconnect Network (LIN) Line pin:
- Internal pull-up resistor and diode
- Protected against ground shorts (LIN pin to
ground)
- Protected against LIN pin loss of ground
- High current drive, 40 mA
≤
I
OL
≤
200 mA
• Automatic thermal shutdown
• On-board Voltage Regulator:
- Output voltage of 5V with ±5% tolerances
over temperature range
- Maximum output current of 50 mA
- Able to drive an external series-pass
transistor for increased current supply
capability
- Internal thermal overload protection
- Internal short-circuit current limit
- External components limited to filter capacitor
only and load capacitor
Package Types
PDIP, SOIC, DFN
RXD
CS/WAKE
V
REG
TXD
1
8
FAULT/SLPS
V
BAT
LIN
V
SS
2
3
4
MCP201
7
6
5
Block Diagram
Voltage
Regulator
V
REG
Internal Circuits
Wake-Up
Logic
Ratiometric
Reference
V
BAT
RXD
CS/WAKE
TXD
FAULT/SLPS
POR
Slope
Control
Thermal
Protection
Vss
OC
approx.
30 kΩ
LIN
©
2007 Microchip Technology Inc.
DS21730F-page 1
MCP201
NOTES:
DS21730F-page 2
©
2007 Microchip Technology Inc.
MCP201
1.0
DEVICE OVERVIEW
1.2
1.2.1
Internal Protection
ESD PROTECTION
The MCP201 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 MCP201 provides a half-duplex, bidirectional
communications interface between a microcontroller
and the serial network bus. This device will translate
the CMOS/TTL logic levels to LIN level logic, and vice
versa.
The LIN specification 1.3 requires that the transceiver
of all nodes in the system be connected via the LIN pin,
referenced to ground and with a maximum external
termination resistance of 510Ω from LIN bus to battery
supply. The 510Ω corresponds to 1 Master and 16
Slave nodes.
The MCP201 provides a +5V 50 mA regulated power
output. The regulator uses a LDO design, is short-
circuit-protected and will turn the regulator output off if
it falls below 3.5V. The MCP201 also includes thermal
shutdown protection. The regulator has been specifi-
cally designed to operate in the automotive environ-
ment and will survive reverse battery connections,
+40V load dump transients and double-battery jumps
(see
Section 1.6 “Internal Voltage Regulator”).
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 hi-impedance level.
1.2.3
THERMAL PROTECTION
The thermal protection circuit monitors the die
temperature and is able to shut down the LIN
transmitter and voltage regulator. Refer to Table 1-1 for
details.
There are three causes for a thermal overload. A
thermal shut down can be triggered by any one, or a
combination of, the following thermal overload
conditions.
• Voltage regulator overload
• LIN bus output overload
• Increase in die temperature due to increase in
environment temperature
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).
Note:
After recovering from a thermal, bus or
voltage regulator overload condition, the
device will be in the Ready1 mode. In order
to go into Operational mode, the CS/
WAKE pin has to be toggled.
1.1
1.1.1
Optional External Protection
TRANSIENT VOLTAGE
PROTECTION (LOAD DUMP)
An external 27V transient suppressor (TVS) diode,
between V
BAT
and ground, with a 50Ω resistor in series
with the battery supply and the V
BAT
pin, serves to pro-
tect the device from power transients (see Figure 1-2)
and ESD events. While this protection is optional, it
should be considered as good engineering practice.
1.1.2
REVERSE BATTERY PROTECTION
An external reverse-battery-blocking diode can be
used to provide polarity protection (see Figure 1-2).
This protection is optional, but should be considered as
good engineering practice.
TABLE 1-1:
TXD
L
H
SOURCES OF THERMAL OVERLOAD
(1,2)
RXD
H
L
Comments
LIN transmitter shutdown, receiver and voltage regulator active, thermal overload
condition.
Regulator shutdown, receiver active, bus contention.
Legend:
x = Don’t care, L = Low, H = High
Note 1:
LIN transceiver overload current on the LIN pin is 200 mA.
2:
Voltage regulator overload current on voltage regulator greater than 50 mA.
©
2007 Microchip Technology Inc.
DS21730F-page 3
MCP201
1.3
Modes of Operation
1.3.3
OPERATION MODE
For an overview of all operational modes, please refer
to Table 1-2.
In this mode, all internal modules are operational.
The MCP201 will go into Power-down mode on the
falling edge of CS/WAKE.
1.3.1
POWER-DOWN MODE
In the Power-down mode, the transmitter and the
voltage regulator are both off. Only the receiver section
and the CS/WAKE pin wake-up circuits are in
operation. This is the lowest power mode.
If any bus activity (e.g., a BREAK character) should
occur during Power-down mode, the device will
immediately enable the voltage regulator. Once the
output has stabilized, the device will enter Ready
mode.
The part will enter the Operation mode, if the CS/WAKE
pin should become active-high (‘1’).
FIGURE 1-1:
CS/WAKE = true
OPERATIONAL MODES
STATE DIAGRAMS
Power-down
Mode
FLT
Bus Activity
CS/WAKE = false
POR
Start
CS/WAKE = false
Operation
Mode
Ready
Mode
FLT
1.3.2
READY AND READY1 MODES
CS/WAKE = true
There are two states for the Ready mode. The only
difference between these states is the transition during
start-up. The state Ready1 mode ensures that the
transition from Ready to Operation mode (once a rising
edge of CS/WAKE) occurs without disrupting bus
traffic.
Immediately upon entering either Ready1 or Ready
mode, the voltage regulator will turn on and provide
power. The transmitter portion of the circuit is off, with
all other circuits (including the receiver) of the MCP201
being fully operational. The LIN pin is kept in a
recessive state.
If a microcontroller is being driven by the voltage
regulator output, it will go through a power-on reset and
initialization sequence. All other circuits, other than the
transmitter, are fully operational. The LIN pin is held in
the recessive state.
The device will stay in Ready mode until the CS/WAKE
pin transitions high (‘1’). After CS/WAKE is active, the
transmitter is enabled and the device enters Operation
mode.
The device may only enter Power-down mode after
going through the Operation mode step.
At power-on of the V
BAT
supply pin, the component is
in either Ready or Ready1 mode, waiting for a
CS/WAKE rising edge.
The MCP201 will stay in either mode for 600 µs as the
regulator powers its internal circuitry and waits until the
CS/WAKE pin transitions high. During the 600 µs
delay, the MCP201 will not recognize a CS/WAKE
event. The CS/WAKE transition from low to high should
not occur until after this delay.
• The CS input is edge, not level, sensitive.
• The CS pin is not monitored until approximately
600 µs after V
REG
has stabized.
• The transistion from Ready1 to Ready is made on
the falling edge of CS.
• The transition from Ready mode to Operational
mode is on the rising edge of CS.
DS21730F-page 4
CS/WAKE = false
Ready1
Mode
CS/WAKE = true
Note:
After power-on, CS will not be sampled
until V
REG
has stabized and an additional
600 µs has elapsed. The microcontroller
should toggle CS approximately 1mS after
RESET to ensure that CS will be recog-
nized.
While the MCP201 is in shutdown, TXD
should not be actively driven high. If TXD
is driven high actively, it may power
internal logic.
Note:
1.3.4
DESCRIPTION OF BROWNOUT
CONDITIONS
As V
BAT
decreases V
REG
is regulated to 5.0 VDC (see
V
REG
in
Section 2.2 “DC Specifications”)
while V
BAT
is greater than 5.5 - 6.0 VDC.
As V
BAT
decreases further V
REG
tracks V
BAT
(V
REG
=
V
BAT
- (0.5 to 1.0) VDC.
The MCP201 monitors V
REG
and as long as V
REG
does
not fall below V
SD
(see V
SD
in
Section 2.2 “DC Spec-
ifications”),
V
REG
will remain powered.
As V
BAT
increases V
REG
will continue to track V
BAT
until V
REG
reaches 5.0 VDC.
If V
REG
falls below V
SD
, V
REG
is turned off and the
MCP201 powers itself down.
The MCP201 will remain powered down until V
BAT
increases above V
ON
(see V
ON
in
Section 2.2 “DC
Specifications”.
©
2007 Microchip Technology Inc.
MCP201
TABLE 1-2:
State
POR
OVERVIEW OF OPERATIONAL MODES
Transmitter
OFF
Voltage Regulator
OFF
Operation
Read CS/WAKE.
If low, then READY.
If high, READY1 mode.
Comments
Sample FAULT/SLPS and
select slope
Ready
Ready1
Operation
Power-down
OFF
OFF
ON
OFF
ON
ON
ON
OFF
If CS/WAKE rising edge, then Bus Off state
Operation mode.
If CS/WAKE falling edge,
then READY mode.
If CS/WAKE falling edge,
then Power down.
Bus Off state
Normal Operation mode
On LIN bus falling, go to
Low-Power mode
READY mode.
On CS/WAKE rising edge, go
to Operational mode
Note:
After power-on, CS will not be sampled until V
REG
has stabized and an additional 600 µs has elapsed. The
microcontroller should toggle CS approximately 1mS after RESET to ensure that CS will be recognized.
©
2007 Microchip Technology Inc.
DS21730F-page 5
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