Datasheet

MCP2003/4
DS22230A-page 8  2010 Microchip Technology Inc.
1.5 Pin Descriptions
TABLE 1-1: PINOUT DESCRIPTIONS
1.5.1 RECEIVE DATA OUTPUT (R
XD)
The Receive Data Output pin is a open drain (OD)
output and follows the state of the LIN pin.
1.5.2 CS (CHIP SELECT)
Chip Select Input pin. An internal pull-down resistor will
keep the CS pin low. This is done to ensure that no
disruptive data will be present on the bus while the
microcontroller is executing a Power-on Reset and an
I/O initialization sequence. The pin must detect a high
level to activate the transmitter.
If CS = 0 when the V
BB supply is turned on, the device
stays in Ready mode. In Ready mode, the receiver is
on and the LIN transmitter driver is off.
If CS = 1 when the V
BB supply is turned on, the device
will proceed to the Operation mode as soon as internal
voltages stabilize.
This pin may also be used as a local wake-up input
(Refer to Example 1-1). In this implementation, the
microcontroller I/O controlling the CS should be
converted to a high-impedance input allowing the
internal pull-down resistor will keep CS low. An external
switch, or other source, can then wake-up both the
transceiver and the microcontroller (if powered).
1.5.3 WAKE UP INPUT (WAKE)
This pin is only available on the MCP2003.
The WAKE
pin has an internal 800K pull up to VBB. A
falling edge on the WAKE
pin causes the device to
wake from Power Down mode. Upon waking, the
MCP2003 will enter Ready mode
1.5.4 FAULT/TXE
This pin is only available on the MCP2004. This pin is
bidirectional and allows disabling of the transmitter, as
well as fault reporting related to disabling the
transmitter. This pin is an open-drain output with states
as defined in Tabl e 1-2 . The transmitter is disabled
whenever this pin is low (‘0’), either from an internal
Fault condition or by an external drive. While the
transmitter is disabled, the internal 30 k pull-up
resistor on the L
BUS pin is also disconnected to reduce
current.
Pin Name
8-Pin
PDIP,
SOIC
8-Pin
DFN
MCP2003 MCP2004
Normal Operation Normal Operation
R
XD 1 1 Receive Data Output (OD) Receive Data Output (OD)
CS 2 2 Chip Select (TTL) Chip Select/Local WAKE (TTL)
WAKE (MCP2003 only)
FAULT/TXE (MCP2004
only)
3 3 Wake up, HV tolerant Fault Detect Output (OD)
Transmitter Enable (TTL)
T
XD 4 4 Transmit Data Input (TTL) Transmit Data Input (TTL)
V
SS 5 5 Ground Ground
L
BUS 6 6 LIN bus (bidirectional) LIN bus (bidirectional)
V
BB 7 7 Battery positive Battery positive
V
REN 8 8 Voltage Regulator Enable Output Voltage Regulator Enable Output
EP — 9 Exposed Thermal Pad. Do not
electrically connect or connect to
Vss
Exposed Thermal Pad. Do not
electrically connect or connect to
Vss
Legend: TTL = TTL Input Buffer; OD = Open-Drain Output
Note: It is not recommended to tie CS high as
this can result the MCP2003/4 entering
Operation mode before the microcon-
troller is initialized and may result in
unintentional LIN traffic.
Note: The FAULT/TXE pin is true (‘0’) whenever
the internal circuits have detected a short
or thermal excursion and have disabled
the L
BUS output driver.