TLE6286 Datasheet, PDF (7/19 Pages) Infineon Technologies AG – LIN-Transceiver LDO

Target Data TLE 6286
In case the voltage regulator control input is not connected to INH output or the
microcontroller is active respectively, the TLE6286 can be set in normal operation mode
without a wake-up via the communication bus.
2.2 LIN Transceiver
The LIN Transceiver has already a pull up resistor of 30kΩ as termination implemented.
There is also a diode in this path, to protect the circuit from feedback of voltages from
the bus line to the power supply. To configure the TLE 6286 as a master node, an
additional external termination resistor of 1kΩ is required. To avoid reverse currents from
the bus line into the battery supply line in case of an unpowered node, it is also
recommended to place a diode in series to the external pull up. For small systems (low
bus capacitance) the EMC performance of the system is supported by an additional
capacitor of at least 1nF in the master node (see figure 6, application circuit).
An capacitor of 10µF at the supply voltage input V_S buffers the input voltage. In
combination with the required reverse polarity diode this prevents the device from
detecting power down conditions in case of negative transients on the supply line.
2.3 Voltage Regulator
The control amplifier compares a reference voltage, which is kept highly accurate by
resistance adjustment, to a voltage that is proportional to the output voltage and drives
the base of the series transistor via a buffer. Saturation control as a function of the load
current prevents any over-saturation of the power element. If the externally scaled down
output voltage at the reset threshold input drops below 1.35 V, the external reset delay
capacitor is discharged by the reset generator. When the voltage of the capacitor
reaches the lower threshold V_DRL, a reset signal occurs at the reset output and is held
until the upper threshold V_DU is exceeded. If the reset threshold input is connected to
GND, reset is triggered at an output voltage of typ. 4.65 V. A connected microcontroller
will be monitored through the watchdog logic. In case of missing pulses at pin W, the
reset output is set to low. The pulse sequence time can be set in a wide range with the
reset delay capacitor. The IC can be switched at the TTL-compatible, low-active inhibit
input. The IC also incorporates a number of internal circuits for protection against
overload, overtemperature, reverse polarity
2.4 Input Capacitor
The input capacitor C_I is necessary for compensation of line influences. Using a resistor
of approx. 1 Ω in series with C_I, the oscillating circuit consisting of input inductivity and
input capacitance can be damped. The output capacitor is necessary for the stability of
the regulating circuit. Stability is guaranteed at values ≥ 22 µF and an ESR of ≤ 3 Ω
within the operating temperature range. For small tolerances of the reset delay the
spread of the capacitance of the delay capacitor and its temperature coefficient should
be noted.
Version 1.02
7
2001-10-15