TH8065 Datasheet, PDF (16/40 Pages) Melexis Microelectronic Systems – Voltage Regulator with LIN Transceiver and Watchdog

TH8065
Voltage Regulator with LIN Transceiver and Watchdog
3.4 VSUP under voltage reset
The under voltage detection unit inhibits an undefined behaviour of the TH8062 under low voltage condition
(VSUP < 4V). If VSUP drops below V_{SUVR_ON} (typ. 3.1V) the under voltage detection becomes active and the
IC will be switched to POR state. The following increasing of VSUP above V_{SUVR_OFF} (typ. 3.7V) cancels this
POR state and the voltage regulator starts with the initialization sequence.
VSUP under voltage in Normal Mode
Supply Voltages below V_{SUVR_OFF} do not influence the voltage regulator. The output voltage Vcc follows
VSUP.
VSUP under voltage in Sleep Mode
No exit from the sleep mode will take place if the VSUP voltage drops down to V_{SUVR_ON} (typ. 3.5V). The
under voltage reset becomes active (POR-state) if the voltage drops below 2.7V. As a result of this
functioning, the sleep mode is left to the normal mode. If VSUP rises again above V_{SUVR_OFF} (typ. 4.2V) the IC
initializes the voltage regulator and continues to work with the normal mode.
The under voltage reset unit secures stable functioning in the under voltage range of VSUP down to GND
level. The dynamic Power-On-Reset secures a defined internal state independent from the duration of the
VSUP drop, which guarantees a stable restart.
VSUP under voltage in Low Slew Mode
The behaviour of TH8062 at low VSUP voltages is equal to the sleep mode. The low slew mode will be
cancelled, if VSUP drops below V_{SUVR_ON} in this mode. The TH8062 enters the normal mode, if VSUP rises
again above V_{SUVR_OFF}.
3.5 Overtemperature Shutdown
If the junction temperature is 155°C < T_J < 175°C the over-temperature recognition will be activated and the
regulator voltage will be switched off. The V_CC voltage drops down, the reset state is entered and the bus-
transceiver is switched off (recessive state).
After T_J falls below 140°C the TH8065 will be initialized again (see Figure 12). This initialisation starts
independently from the voltage levels on EN and BUS. Within the thermal shutdown mode the transceiver
can not switch to the normal mode neither with local nor with remote wake-up.
The operation of the TH8065 is possible between T_Amax (125°C) and the switch off temperature, but small
parameter differences can appear.
After over-temperature switch-off the IC behaves as described in chapter 3.8 RESET and Watchdog.
TH8065 – Datasheet
3901008065
Page 16 of 40
May 2006
Rev 003