TLE7250V_15 Datasheet, PDF (12/34 Pages) Infineon Technologies AG – High Speed CAN-Transceiver

TLE7250VLE
TLE7250VSJ
Functional Description
4.3.1 Power-down State
Independent of the transmitter supply V_CC and of the NEN input pin, the TLE7250V is in power-down state when
the digital supply voltage V_IO is turned off (see Figure 5).
In the power-down state the input resistors of the receiver are disconnected from the bus biasing V_CC/2. The CANH
and CANL bus interface of the TLE7250V is floating and acts as a high-impedance input with a very small leakage
current. The high-ohmic input does not influence the “recessive” level of the CAN network and allows an optimized
EME performance of the entire HS CAN network (see also Table 2).
4.3.2 Forced Power-save Mode
The forced power-save mode is a fail-safe mode to avoid any disturbance on the HS CAN bus, while the
TLE7250V faces a loss of the transmitter supply V_CC.
In forced power-save mode, the transmitter and the normal-mode receiver are turned off and therefore the
transceiver TLE7250V can not disturb the bus media.
The RxD output pin is permanently set to logical “high”. The bus biasing is floating (details see Table 2).
The forced power-save mode can only be entered when the transmitter supply V_CC is not available, either by
powering up the digital supply V_IO only or by turning off the transmitter supply in normal-operating mode. While the
transceiver TLE7250V is in forced power-save mode, switching the NEN input to logical “high” triggers a mode
change to power-save mode (see Figure 5).
4.3.3 Power-up
The HS CAN transceiver TLE7250V powers up if at least the digital supply V_IO is connected to the device. By
default the device powers up in power-save mode, due to the internal pull-up resistor on the NEN pin to V_IO.
In case the device needs to power-up to normal-operating mode, the NEN pin needs to be pulled active to logical
“low” and the supplies V_IO and V_CC have to be connected.
By supplying only the digital power supply V_IO the TLE7250V powers up either in forced power-save mode or in
power-save mode, depending on the signal of the NEN input pin (see Figure 5).
Data Sheet
12
Rev. 1.0, 2015-08-12