MCP2003B Datasheet, PDF (4/32 Pages) Microchip Technology – LIN Transceiver

MCP2003B
1.3 Modes of Operation
For an overview of all operational modes, refer to
Table 1-1.
1.3.1
POWER-DOWN MODE
In Power-Down mode, everything is off except the
wake-up section. The internal 30 k pull-up resistor
switch is open, which enables the high ohmic pull-up
resistor (900 k typical). This is the lowest power
mode. The receiver is off, thus its output is open-drain.
On CS going to a high level or a falling edge on WAKE,
the device will enter Ready mode as soon as internal
voltage stabilizes. Refer to Section 2.4 “AC
Specifications” for further information. In addition, LIN
bus activity will change the device from Power-Down
mode to Ready mode; The MCP2003B wakes up on a
rising edge on LBUS preceded by a low level lasting at
least 70 µs typically. See Figure 1-2 about remote
wake-up. If CS is held high as the device transitions
from Power-Down to Ready mode, the device will
transition to either Operation or Transmitter Off mode,
depending on TXD input, as soon as internal voltages
stabilize.
1.3.2 READY MODE
Transitioning from POR into Ready mode is achieved
when V_BB > V_{BBUV_RISE}. Upon entering Ready mode,
VREN is enabled and the receiver detect circuit is
powered-up. The transmitter remains disabled and the
device is ready to receive data but not to transmit.
Upon VBB supply pin power-on, the device will remain
in Ready mode as long as CS is low. When CS
transitions high, the device will either enter Operation
mode if the TXD pin is held high, or the device will enter
Transmitter Off mode if the TXD pin is held low.
1.3.3 OPERATION MODE
In this mode, all internal modules are operational. Note
that the part cannot transmit if the pull-up resistance is
missing on RX pin. See Section 1.5.1.1 “RXD
Monitoring” for details.
The device will go into Power-Down mode on the falling
edge of CS and the TXD pin is held high. The device will
enter Transmitter Off mode in the event of a Fault con-
dition such as thermal overload, bus contention or TXD
timer expiration.
The VBB to LBUS ~30 kΩ pull-up resistor (RSLAVE) is
connected only in Operation mode.
1.3.4 TRANSMITTER OFF MODE
Transmitter Off mode is reached whenever the
transmitter is disabled due to a Fault condition. Fault
conditions include thermal overload, bus contention,
RXD monitoring and TXD timer expiration.
The device will go into Power-Down mode on the falling
edge of CS, or return to Operation mode if all faults are
resolved.
DS20005463C-page 4
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