MCP2003B datasheet(4/32 Pages) MICROCHIP

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MCP2003B

DS20005463C-page 4

 2015-2016 Microchip Technology Inc.

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

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 VBB > VBBUV_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.

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