TLE6251-2G Datasheet, PDF (20/35 Pages) Infineon Technologies AG – High Speed CAN-Transceiver with Wake and Failure Detection

TLE6251-2G
Fail Safe Features
7.2.5 Over - Temperature Detection
The output driver stage is protected against over temperature. Exceeding the shutdown temperature results in
deactivation of the output driving stage. To avoid any toggling after the device cools down, the output driver stage
is enabled again only after a “Recessive” to “Dominant” signal change on the TxD pin (see Figure 11).
An Over - Temperature event only deactivates the output drive stage, the TLE6251-2G doesn’t change its
operation mode in this failure case. The Over - Temperature event is indicated by a logical “Low” signal on the
NERR pin in Receive - Only Mode.
Temp.
Over – Temperature
Event
CANH
CANL
Device cool
down
Output - Stage
Release
t
t
TxD
t
RxD
t
Normal Operation Mode
Figure 11 Release of the Transmission after an Over - Temperature event
7.3
Under - Voltage Detection
The TLE6251-2G provides a power supply monitoring on all three power supply pins: V_CC, V_IO and V_S. In case of
an under - voltage event on any of this three power supplies, the TLE6251-2G changes the operation mode and
sets an internal failure flag. The internal failure flag is not indicated by the NERR output pin.
7.3.1
Under - Voltage event on V_CC and V_IO
An under - voltage event on the power supply V_CC or the power supply V_IO causes the change of the operation
mode to Sleep Mode, regardless of the operation mode in which the TLE6251-2G might currently operate. The
logical signals on the digital input pins EN and NSTB are also disregarded. After the power supplies V_CC and V_IO
have been reestablished, the operation mode can be changed by a Wake - Up event or by applying a logical “High”
signal to the EN pin or the NSTB pin.
The under - voltage monitoring on the power supply V_CC and V_IO is combined with an internal filter time. Only if the
voltage drop on each of these two power supplies is longer present as the time t_Drop > t_UV(VIO) (t_Drop > t_UV(VCC)) the
operation mode change will be activated (see Figure 12).
Under - voltage events on the power supplies V_CC or V_IO are not indicated by the NERR pin nor by the RxD pin.
Data Sheet
20
Rev. 1.0, 2009-05-07