General description

The UJA1078A 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 UJA1078A 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.

The core SBC contains the following integrated devices:

• High-speed CAN transceiver, inter-operable and downward compatible with CAN

transceiver TJA1042, and compatible with the ISO 11898-2 and ISO 11898-5

standards

• LIN transceivers compliant with LIN 2.1, LIN 2.0 and SAE J2602, and compatible with

LIN 1.3

• Advanced independent watchdog (UJA1078A/xx/WD versions)

• 250 mA voltage regulator for supplying a microcontroller; extendable with external

PNP transistor for increased current capability and dissipation distribution

• Separate voltage regulator for supplying the on-board CAN transceiver

• 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 UJA1078A is designed to be used in combination with a microcontroller that

incorporates a CAN controller. The SBC ensures that the microcontroller always starts up

in a controlled manner.

Features and benefits

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:

Enhanced ElectroMagnetic Compatibility (EMC) performance

±8 kV ElectroStatic Discharge (ESD) protection Human Body Model (HBM) on the

CAN/LIN bus pins and the wake-up pins

±6 kV ElectroStatic Discharge protection IEC 61000-4-2 on the CAN/LIN bus pins

and the wake-up 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; Restriction of Hazardous Substances Directive (RoHS) and dark green

compliant

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

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

Power management

Wake-up via CAN, 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/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

Voltage regulators

Main 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

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