High-Speed CAN Fail-Safe System Basis Chip

UJA1066TW

The UJA1066 fail-safe System Basis Chip (SBC) replaces basic discrete components which are common in every Electronic Control Unit (ECU) with a Controller Area Network (CAN) interface. The fail-safe SBC supports all networking applications that control various power and sensor peripherals by using high-speed CAN as the main network interface. The fail-safe SBC contains the following integrated devices:

  • High-speed CAN transceiver, interoperable and downward compatible with CAN transceiver TJA1041 and TJA1041A, and compatible with the ISO 11898-2 standard and the ISO 11898-5 standard (in preparation)
  • Advanced independent watchdog
  • Dedicated voltage regulators for microcontroller and CAN transceiver
  • Serial peripheral interface (full duplex)
  • Local wake-up input port
  • Inhibit/limp-home output port

In addition to the advantages of integrating these common ECU functions in a single package, the fail-safe SBC offers an intelligent combination of system-specific functions such as:

  • Advanced low-power concept
  • Safe and controlled system start-up behavior
  • Advanced fail-safe system behavior that prevents any conceivable deadlock
  • Detailed status reporting on system and subsystem levels

The UJA1066 is designed to be used in combination with a microcontroller that incorporates a CAN controller. The fail-safe SBC ensures that the microcontroller is always started up in a defined manner. In failure situations, the fail-safe SBC will maintain microcontroller functionality for as long as possible to provide a full monitoring and software-driven fallback operation.

The UJA1066 is designed for 14 V single power supply architectures and for 14 V and 42 V dual power supply architectures.

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Product Details

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Features

2.1 General
  • Contains a full set of CAN ECU functions:
    • CAN transceiver
    • Voltage regulator for the microcontroller (3.3 V or 5.0 V)
    • Separate voltage regulator for the CAN transceiver (5 V)
    • Enhanced window watchdog with on-chip oscillator
    • Serial Peripheral Interface (SPI) for the microcontroller
    • ECU power management system
    • Fully integrated autonomous fail-safe system
  • Designed for automotive applications:
    • Supports 14 V and 42 V architectures
    • Excellent ElectroMagnetic Compatibility (EMC) performance
    • ±8 kV ElectroStatic Discharge (ESD) protection Human Body Model (HBM) for off-board pins
    • ±4 kV ElectroStatic Discharge (ESD) protection IEC 61000-4-2 for off-board pins
    • ±60 V short-circuit proof CAN-bus pins
    • Battery and CAN-bus pins are protected against transients in accordance with ISO 7637-3
    • Very low sleep current
  • Supports remote flash programming via the CAN-bus
  • Small 8 mm × 11 mm HTSSOP32 package with low thermal resistance

2.2 CAN transceiver

  • ISO 11898-2 and ISO 11898-5 compliant high-speed CAN transceiver
  • Enhanced error signalling and reporting
  • Dedicated low dropout voltage regulator for the CAN-bus:
    • Independent of the microcontroller supply
    • Guarded by CAN-bus failure management
    • Significantly improves EMC performance
  • Partial networking option with global wake-up feature; allows selective CAN-bus communication without waking up sleeping nodes
  • Bus connections are truly floating when power is off
  • SPLIT output pin for stabilizing the recessive bus level

2.3 Power management

  • Smart operating modes and power management modes
  • Cyclic wake-up capability in Standby and Sleep modes
  • Local wake-up input with cyclic supply feature
  • Remote wake-up capability via the CAN-bus
  • External voltage regulators can easily be incorporated into the power supply system (flexible and fail-safe)
  • 42 V battery-related high-side switch for driving external loads such as relays and wake-up switches
  • Intelligent maskable interrupt output

2.4 Fail-safe features

  • Safe and predictable behavior under all conditions
  • Programmable fail-safe coded window and time-out watchdog with on-chip oscillator, guaranteeing autonomous fail-safe system supervision
  • Fail-safe coded 16-bit SPI interface for the microcontroller
  • Global enable pin for the control of safety-critical hardware
  • Detection and detailed reporting of failures:
    • On-chip oscillator failure and watchdog alerts
    • Battery and voltage regulator undervoltages
    • CAN-bus failures (short circuits and open-circuit bus wires)
    • TXD and RXD clamping situations and short circuits
    • Clamped or open reset line
    • SPI message errors
    • Overtemperature warning
    • ECU ground shift (two selectable thresholds)
  • Rigorous error handling based on diagnostics
  • Supply failure early warning allows critical data to be stored
  • 23 bits of access-protected RAM available (e.g. for logging cyclic problems)
  • Reporting in a single SPI message; no assembly of multiple SPI frames needed
  • Limp-home output signal for activating application hardware in case system enters Fail-safe mode (e.g. for switching on warning lights)
  • Fail-safe coded activation of Software development mode and Flash mode
  • One SPI readable device type identification
  • Software-initiated system reset

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