The UJA1079A core System Basis Chip (SBC) replaces the basic discrete components commonly found in Electronic Control Units (ECU) with a Local Interconnect Network (LIN) interface.
The UJA1079A supports the networking applications used to control power and sensor peripherals by using the LIN interface as a local sub-bus.
The core SBC contains the following integrated devices:
* LIN transceiver compliant with LIN 2.1, LIN 2.0 and SAE J2602, and compatible with LIN 1.3
* 250 mA voltage regulator for supplying a microcontroller; extendable with external PNP transistor for increased current capability and dissipation distribution
* Serial Peripheral Interface (SPI) (full duplex)
* 2 local wake-up input ports
* Limp home output port
In addition to the advantages gained from integrating these common ECU functions in a single package, the core SBC offers an intelligent combination of system-specific functions such as:
* Advanced low-power concept
* Safe and controlled system start-up behavior
* Detailed status reporting on system and sub-system levels
The UJA1079A is designed to be used in combination with a microcontroller. The SBC ensures that the microcontroller always starts up in a controlled manner.
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## Features
**2.1 General**
* Contains LIN ECU functions:
* LIN transceiver
* Scalable 3.3 V or 5 V voltage regulator delivering up to 250 mA for a microcontroller and peripheral circuitry; an external PNP transistor can be connected for better heat distribution over the PCB
* Watchdog with Window and Timeout modes and on-chip oscillator
* Serial Peripheral Interface (SPI) for communicating with the microcontroller
* ±8 kV ElectroStatic Discharge (ESD) protection Human Body Model (HBM) on the LIN bus pin and the wake-up pins
* ±6 kV ElectroStatic Discharge protection IEC 61000-4-2 on the LIN bus pin and the wake-up pins
* ±58 V short-circuit proof LIN bus pin
* Battery and LIN bus pins are protected against transients in accordance with ISO 7637-3
* Small 6.1 mm × 11 mm HTSSOP32 package with low thermal resistance
* Pb-free; Restriction of Hazardous Substances Directive (RoHS) and dark green compliant
**LIN transceiver**
* LIN 2.1 compliant LIN transceiver
* Compliant with SAE J2602
* Downward compatible with LIN 2.0 and LIN 1.3
* Low slope mode for optimized EMC performance
* Integrated LIN termination diode at pin DLIN
**Power management**
* Wake-up via LIN or local wake-up pins with wake-up source detection
* 2 wake-up pins:
* WAKE1 and WAKE2 inputs can be switched off to reduce current flow
* Output signal (WBIAS) to bias the wake-up pins, selectable sampling time of 16 ms or 64 ms
* Standby mode with very low standby current and full wake-up capability; V1 active to maintain supply to the microcontroller
* Sleep mode with very low sleep current and full wake-up capability
**Control and diagnostic features**
* Safe and predictable behavior under all conditions
* Programmable watchdog with independent clock source
* Window, Timeout (with optional cyclic wake-up) and Off modes supported (with automatic re-enable in the event of an interrupt)
* 16-bit Serial Peripheral Interface (SPI) for configuration, control and diagnosis
* Global enable output for controlling safety-critical hardware
* Limp home output (LIMP) for activating application-specific ‘limp home’ hardware in the event of a serious system malfunction
* Overtemperature shutdown
* Interrupt output pin; interrupts can be individually configured to signal V1 undervoltage, LIN/local wake-up and cyclic and power-on interrupt events
* Bidirectional reset pin with variable power-on reset length to support a variety of microcontrollers
* Software-initiated system reset
**Voltage regulator V1**
* Scalable voltage regulator for the microcontroller, its peripherals and additional external transceivers
* ±2 % accuracy
* 3.3 V and 5 V versions available
* Delivers up to 250 mA and can be combined with an external PNP transistor for better heat distribution over the PCB
* Selectable current threshold at which the external PNP transistor starts to deliver current
* Undervoltage warning at 90 % of nominal output voltage and undervoltage reset at 90 % or 70 % of nominal output voltage
* Can operate at VBAT voltages down to 4.5 V (e.g. during cranking), in accordance with ISO 7637 pulse 4/4b and ISO16750-2
