General description

The UJA1078 core System Basis Chip (SBC) replaces the basic discrete components commonly found in Electronic Control Units (ECU) with a high-speed Controller Area Network (CAN) and two Local Interconnect Network (LIN) interfaces.

The UJA1078 supports the networking applications used to control power and sensor peripherals by using a high-speed CAN as the main network interface and the LIN interfaces as local sub-busses.

Features and benefits

2.1 General

■ Contains a full set of CAN and LIN ECU functions:

♦ CAN transceiver and two LIN transceivers

♦ 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

♦ Separate voltage regulator for the CAN transceiver (5 V)

♦ Watchdog with Window and Timeout modes and on-chip oscillator

♦ Serial Peripheral Interface (SPI) for communicating with the microcontroller

♦ ECU power management system

■ Designed for automotive applications:

♦ Excellent ElectroMagnetic Compatibility (EMC) performance

♦ ±8 kV ElectroStatic Discharge (ESD) protection Human Body Model (HBM) on the CAN/LIN bus pins and the WAKE pins

♦ ±6 kV ElectroStatic Discharge (ESD) protection IEC 61000-4-2 on the CAN/LIN bus pins and the WAKE pins

♦ ±58 V short-circuit proof CAN/LIN bus pins

♦ Battery and CAN/LIN bus pins are protected against transients in accordance with ISO 7637-3

■ Supports remote flash programming via the CAN bus

■ Small 6.1 mm × 11 mm HTSSOP32 package with low thermal resistance

■ Pb-free; RoHS and dark green compliant

2.2 CAN transceiver

■ ISO 11898-2 and ISO 11898-5 compliant high-speed CAN transceiver

■ Dedicated low dropout voltage regulator for the CAN bus:

♦ Independent of the microcontroller supply

♦ Significantly improves EMC performance

■ Bus connections are truly floating when power is off

■ SPLIT output pin for stabilizing the recessive bus level

2.3 LIN transceivers

■ 2 × LIN 2.1 compliant LIN transceivers

■ 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

2.4 Power management

■ Wake-up via CAN, LIN or local WAKE pins with wake-up source detection

■ 2 WAKE pins:

■ ♦ WAKE1 and WAKE2 inputs can be switched off to reduce current flow

■ ♦ Output signal (WBIAS) to bias the WAKE 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

2.5 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/V2 undervoltage, CAN/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

2.6 Voltage regulators

■ Main voltage regulator V1:

♦ Scalable voltage regulator for the microcontroller, its peripherals and additional external transceivers

♦ ±2 % accuracy for LIN master application

♦ ±3 % accuracy for LIN slave application

♦ 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

♦ Stable output under all conditions

■ Voltage regulator V2 for CAN transceiver:

♦ Dedicated voltage regulator for on-chip high-speed CAN transceiver

♦ Undervoltage warning at 90 % of nominal output voltage

♦ Can be switched off; CAN transceiver can be supplied by V1 or by an external voltage regulator

♦ Can operate at VBAT voltages down to 5.5 V (e.g. during cranking) in accordance with ISO 7637, pulse 4

♦ Stable output under all conditions