UJA1078ATW/3V3WD,1

Specialized Overview

The UJA1078ATW/3V3WD,1 is a high-speed CAN/dual LIN core System Basis Chip (SBC) from NXP Semiconductors. It integrates a high-speed CAN transceiver compliant with ISO 11898-2 and ISO 11898-5, two LIN transceivers supporting LIN 2.2A and SAE J2602, and an advanced independent watchdog. The device features a scalable 3.3 V main voltage regulator (V1) delivering up to 250 mA for microcontroller supply, extendable via external PNP transistor. A separate 5 V voltage regulator (V2) powers the on-board CAN transceiver. Communication with the host microcontroller is facilitated through a full-duplex 16-bit Serial Peripheral Interface (SPI).

Specialized Feature Summary

• Integrates a high-speed CAN transceiver and dual LIN transceivers within a single package.
• Features a programmable watchdog with Window and Timeout modes supported by an on-chip oscillator.
• Includes a dedicated low-dropout voltage regulator for the CAN transceiver to enhance EMC performance.
• Provides wake-up capabilities via CAN, LIN, or local input pins with source detection.

Specialized Applications

• Electronic Control Units (ECU) requiring integrated power management and networking.
• Automotive sensor peripheral control systems.
• Power distribution networks utilizing CAN as the main interface and LIN as local sub-busses.

Specialized Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to confirm the presence of the watchdog feature and the exact output voltage level of the primary regulator. Ensure the component matches the required automotive qualification standards for the intended application environment.

Specialized Selection Notes

Select this variant when a 3.3 V output is required for the microcontroller supply. Confirm that the system design accommodates the HTSSOP32 package dimensions and thermal requirements. Verify compatibility with the host microcontroller's SPI interface and reset timing specifications.

Specialized Part Context

This component belongs to the UJA1078A family of System Basis Chips designed to replace discrete components in Electronic Control Units. It consolidates CAN/LIN communication interfaces, power regulation, and system control functions into a compact form factor suitable for modern automotive electronics architectures.

Specialized Replacement Considerations

The datasheet indicates downward compatibility with the TJA1042 CAN transceiver. However, direct pin-to-pin replacement requires verification of register maps and voltage regulator configurations against the legacy component specifications.

Specialized FAQ

What is the function of the WDOFF pin?

The WDOFF pin is used to deactivate the watchdog. 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 capability be increased?

Yes, the 250 mA main voltage regulator can be extended with an external PNP transistor to increase current capability and improve heat distribution across the PCB.