Datasheet

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Supply Voltage (V
SUP
)
Ground (GND)
Enable Input Pin (EN)
NWake Input Pin (NWake)
Inhibit Output Pin (INH)
TPIC1021
LIN Physical Interface
SLIS113C – OCTOBER 2004 – REVISED JULY 2005
RXD Wake-up Request
When the TPIC1021 has been in low power mode and encounters a wake-up event from the LIN bus or NWake
pin the RXD pin will go LOW while the device enters and remains in Standby Mode (until EN is re-asserted high
and the device enters Normal Mode).
The TPIC1021 device power supply pin. This pin is connected to the battery through an external reverse battery
blocking diode. The continuous DC operating voltage range for the TPIC1021 is from 7 V to +27 V. The V
SUP
is
protected to for harsh automotive conditions of up to + 40 V.
The device contains a reset circuit to avoid false bus messages during under-voltage conditions when V
SUP
is
less than V
SUP_UNDER
.
TPIC1021 device ground connection. The TPIC1021 can operate with a ground shift as long as the ground shift
does not reduce V
SUP
below the minimum operating voltage. If there is a loss of ground at the ECU level, the
TPIC1021 will not have a significant current consumption on the LIN pin while in the recessive state (<100 µA
sourced via the LIN pin) and for the dominant state the pull-up resistor should be active.
The enable input pin controls the operation mode of the TPIC1021 (Normal or Low Power Mode). When enable
is high, the TPIC1021 is in normal mode allowing a transmission path from TXD to LIN and from LIN to RXD.
When the enable input is low, the device is put into low power (sleep) mode and there are no transmission paths.
The device can enter normal operating mode only after being woken up. The enable pin has an internal
pull-down resistor to ensure the device remains in low power mode even if the enable pin floats.
The NWake input pin is a high-voltage input used to wake up the TPIC1021 from low power mode. NWake is
usually connected to an external switch in the application. A falling edge on NWake with a low that is asserted
longer than the filter time (t
NWAKE
) results in a local wake-up. The NWake pin provides an internal pull-up current
source to V
SUP
.
The inhibit output pin is used to control an external voltage regulator that has an inhibit input. When the
TPIC1021 is in normal operating mode, the inhibit high-side switch is enabled and the external voltage regulator
is activated. When TPIC1021 is in low power mode, the inhibit switch is turned off, which disables the voltage
regulator. A wake-up event on for the TPIC1021 will return the INH pin to V
SUP
level. The INH pin output current
is limited to 2 mA. The INH pin can also drive an external transistor connected to an MCU interrupt input.
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