MCP2025 Datasheet, PDF (3/36 Pages) Microchip Technology – LIN Transceiver with Voltage Regulator

MCP2025
1.0 FUNCTION DESCRIPTION
The MCP2025 provides a physical interface between a
microcontroller and a LIN half-duplex bus. It is intended
for automotive and industrial applications with serial
bus baud rates up to 20 kbaud. This device will
translate the CMOS/TTL logic levels to LIN logic levels,
and vice versa. The device offers optimum EMI and
ESD performance; it can withstand high voltage on the
LIN bus. The device supports two low-power modes to
meet automotive industry power consumption
requirements. The MCP2025 also provides a +5V or
3.3V 70 mA regulated power output.
FIGURE 1-1:
STATE DIAGRAM
1.1 Modes of Operation
The MCP2025 works in five modes: POWER-ON-
RESET mode, POWER-DOWN mode, READY mode,
OPERATION mode, and TRANSMITTER-OFF mode.
For an overview of all operational modes, please refer
to Table 1-1. For the operational mode transition,
please refer to Figure 1-1.
POR⁽²⁾
VREG OFF
RX OFF
TX OFF
VBB>V_ON
CS/LWAKE=0
READY
VREG ON
RX ON
TX OFF
CS/LWAKE=1 OR
Voltage Rising Edge on LBUS
CS=1 &TXD=0&
VREG_OK=1⁽¹⁾
TX OFF
VREG ON
RX ON
TX OFF
CS/LWAKE=0
&TXD=0
POWER-DOWN
VREG OFF
RX OFF
TX OFF
CS/LWAKE=1 &TXD=1
VREG_OK=1⁽¹⁾
CS/LWAKE=1&
TXD=1&
No Fault⁽³⁾
CS/LWAKE=0 or
Fault detected⁽³⁾
OPERATION
VREG ON
RX ON
TX ON
Note 1: VREG_OK : Regulator Output Voltage > 0.8VREG_NOM.
2: If the voltage on pin VBB falls below V_OFF, the device will enter POWER-ON RESET mode from all other
modes, which is not shown in the figure.
3: Faults include TXD/LBUS permanent dominant, LBUS short to VBB, thermal protection, and VREG_OK
is false.
1.1.1 POWER-ON-RESET MODE
Upon application of VBB, or whenever the voltage on
VBB is below the threshold of regulator turn off voltage
VOFF (typically 4.50V), the device enters POWER-ON-
RESET mode (POR). During this mode, the device
maintains the digital section in a reset mode and waits
until the voltage on pin VBB rises above the threshold
of regulator turn on voltage VON (typically 5.75V) to
enter READY mode. In POWER-ON-RESET mode,
the LIN physical layer and voltage regulator are
disabled, and the RESET pin is switched to ground.
 2012 Microchip Technology Inc.
DS22306A-page 3