Datasheet

13

Rev. 1.11

2019-09-19

High Speed CAN Transceiver

TLE9251V

Changing the mode of operation

7

Changing the mode of operation

7.1

Power-up and power-down

The HS CAN transceiver TLE9251V powers up by applying the digital supply VIO to the device (VIO > VIO(U,R)).

After powering up, the device enters one out of three operating modes (see Figure 5 and Figure 6).

Depending on the condition of the transmitter supply voltage VCC and the mode selection pin STB the device

can enter every mode of operation after the power-up:

• VCC is available and STB input is set to “low” - Normal-operating mode

• VCC is disabled and the STB input is set to “low” - Forced-receive-only mode

• STB input is set to “high” - Stand-by mode

The device TLE9251V powers down when the VIO supply falls below the undervoltage detection threshold

(VIO < VIO(U,F)), regardless if the transmitter supply VCC is available or not. The power-down detection is active in

every mode of operation.

Figure 5

Power-up and power-down

Figure 6

Power-up and power-down timings

STB

VCC

VIO

power-down

state

“X”

“X”

“off”

Normal-operating

mode

STB

VCC

VIO

0

“on”

“on”

Forced-

receive-only

mode

STB

VCC

VIO

0

“off”

“on”

Stand-by

mode

STB

VCC

VIO

1

“X”

“on”

VIO “on”

VCC “off”

STB “0”

VIO “on”

VCC “on”

STB “0”

VIO “on”

STB “1”

VIO “off”

VIO “off”

VIO “off”

VIO “off”

“blue” -> indicates the event triggering the

power-up or power-down

“red” -> indicates the condition which is

required to reach a certain operating mode

t

STB

“X” = don’t care

“high” due the internal

pull-up resistor1)

VIO

t

VIO undervoltage monitor

VIO(UV,F)

VIO undervoltage monitor

VIO(UV,R)

transmitter supply voltage VCC = “don’t care”

Power-down state

any mode of operation

Stand-by mode

tPON

hysteresis

VIO(UV,H)

tPOFF

1) assuming no external signal applied

"0" for Normal-operating mode

"1" for Stand-by mode