UJA1078ATW/5V0,118

Specialized Overview

The UJA1078ATW/5V0,118 is a System Basis Chip (SBC) from NXP Semiconductors designed for automotive Electronic Control Units. It integrates a high-speed CAN transceiver compliant with ISO 11898-2 and ISO 11898-5 standards, alongside two LIN transceivers supporting LIN 2.2A and SAE J2602 protocols. The device features a scalable 5 V main voltage regulator delivering up to 250 mA for microcontroller supply, extendable via an external PNP transistor. A dedicated 5 V regulator supplies the on-chip CAN transceiver. Key functional blocks include a programmable watchdog, a full-duplex 16-bit Serial Peripheral Interface (SPI), two local wake-up input ports, and a limp home output port. The component operates within a temperature range of -40 °C to 125 °C and is housed in a 32-lead HTSSOP package.

Specialized Feature Summary

• Integrates high-speed CAN and dual LIN interfaces with advanced low-power management modes including Standby and Sleep.
• Features a scalable 5 V voltage regulator capable of supplying up to 250 mA, with provisions for external current extension.
• Includes a programmable independent watchdog with Window and Timeout modes for system reliability monitoring.
• Provides detailed status reporting and diagnostic capabilities through a 16-bit SPI interface.

Specialized Applications

• Automotive Electronic Control Units (ECU)
• Power and sensor peripheral control networks
• Gateway applications utilizing CAN as the main bus and LIN as sub-busses

Specialized Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm regulatory compliance and feature set variations. Ensure that the selected variant matches the required voltage regulator configuration and presence of integrated watchdog functionality before procurement.

Specialized Selection Notes

Select this component when a unified solution for CAN and LIN communication is required within a single package. Consider the thermal dissipation requirements of the 250 mA regulator and determine if an external PNP transistor is necessary for optimal heat distribution across the printed circuit board layout.

Specialized Part Context

This part belongs to the UJA1078A family of System Basis Chips. Variants within this series differ primarily by the output voltage of the main regulator (3.3 V or 5 V) and the inclusion of an integrated watchdog timer, indicated by specific suffixes in the part number.

Specialized Replacement Considerations

The integrated CAN transceiver section is downward compatible with the TJA1042. However, direct pin-to-pin replacement requires verifying that the alternative component supports the dual LIN interface and the specific power management features of the UJA1078A.

Specialized FAQ

What is the function of the WDOFF pin?

The WDOFF pin is used to deactivate the watchdog timer. When driven HIGH, it disables the watchdog and results in a software reset.

How does the device handle overtemperature conditions?

If the chip temperature exceeds the activation threshold, the SBC enters Overtemp mode, switching off voltage regulators and driving the LIMP pin LOW to activate limp home hardware.

Can the main voltage regulator current be increased?

Yes, the 250 mA output can be extended by connecting an external PNP transistor to improve current capability and distribute heat dissipation.