UJA1075TW/3V3/WD:1

Specialized Overview

The UJA1075TW/3V3/WD:1 is a System Basis Chip (SBC) integrating high-speed CAN and LIN transceivers with power management. It features a scalable 3.3 V main voltage regulator delivering up to 250 mA for microcontrollers, extendable via external PNP transistors. A separate 5 V regulator supplies the on-chip CAN transceiver. The device includes an advanced independent watchdog with window and timeout modes, two local wake-up inputs, and a limp home output. Communication with the host microcontroller occurs via a full-duplex Serial Peripheral Interface (SPI).

Specialized Feature Summary

• Integrates ISO 11898-2 compliant high-speed CAN transceiver and LIN 2.1 compliant transceiver.
• Provides scalable 3.3 V voltage regulation with undervoltage detection and reset capabilities.
• Includes programmable watchdog timer with independent clock source and multiple operating modes.
• Supports advanced low-power concepts with distinct Standby and Sleep modes for current optimization.

Specialized Applications

• Automotive Electronic Control Units (ECU) requiring integrated bus communication and power management.
• Network applications controlling power and sensor peripherals using CAN as the main interface.
• Systems utilizing LIN as a local sub-bus for peripheral control.

Specialized Procurement Notes

Verify the ordering suffix matches the required regulator voltage and feature set. The TW designation indicates the HTSSOP32 package type. Confirm the presence of the WD suffix ensures the inclusion of the watchdog functionality. Ensure compatibility with the specific microcontroller interface requirements before finalizing procurement orders.

Specialized Selection Notes

Select this variant specifically when a 3.3 V supply rail is required for the microcontroller. Compare against the 5 V version if higher current capability or different logic levels are needed. Consider the external PNP transistor option if PCB thermal dissipation requires load sharing beyond the internal 250 mA limit. Verify SPI timing constraints match the host controller specifications.

Specialized Part Context

This component belongs to the NXP UJA1075 family of System Basis Chips designed for automotive environments. It consolidates discrete ECU components into a single package to reduce board space and improve reliability. The family offers variations in regulator voltage and watchdog inclusion to suit diverse microcontroller architectures.

Specialized Replacement Considerations

Direct substitutes within the same family include the UJA1075TW/5V0/WD variant, which provides a 5 V regulator instead of 3.3 V. Other versions like the UJA1075TW/3V3 lack the watchdog function. Cross-manufacturer replacements require careful evaluation of pinout compatibility and electrical parameter alignment.

Specialized FAQ

How does the UJA1075 handle system startup?

The SBC ensures the microcontroller starts up in a controlled manner by managing power-on sequences and providing configurable reset pulse widths via the RSTN pin.

What protection features are included for the bus lines?

The CAN/LIN bus pins offer ±8 kV HBM ESD protection, ±6 kV IEC 61000-4-2 protection, and are short-circuit proof up to ±58 V.

Can the main voltage regulator current be extended?

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