UJA1078TW: High-speed CAN/dual LIN core system basis chip ARCHIVED

Overview

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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.

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 (UJA1078/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 UJA1078 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.

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Features

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

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 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

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 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