Automotive 4.5V to 40V, 1.3A Buck Converter with 4 LDOs for Microcontrollers - TPS65381-Q1

TPS65381-Q1 (NRND)

Automotive 4.5V to 40V, 1.3A Buck Converter with 4 LDOs for Microcontrollers


Not Recommended for New Designs (NRND)

Replaced By TPS65381A-Q1– The device is an EXACT EQUIVALENT in functionality and parametrics to the compared device.

TI does not recommend using this part in a new design. This product continues to be in production to support existing customers.


The TPS65381-Q1 device is a multi-rail power supply designed to supply microcontrollers (MCUs) in functional safety applications, such as those found in automotive and industrial applications. The device supports Texas Instruments’ TMS570LS series flash MCU and other MCUs with dual-core lockstep (LS) or loosely-coupled architectures (LC).

The TPS65381-Q1 device integrates multiple supply rails to power the MCU, CAN, or FlexRay, and an external sensor. An asynchronous-buck switch-mode power-supply converter with an internal FET converts the input battery voltage to a 6-V preregulator output. This 6-V preregulator supplies the other regulators. Furthermore, the device supports wake-up from IGNITION or wake-up from the CAN transceiver.

A fixed 5-V linear regulator with an internal FET is integrated to be used as a CAN supply (as one example). A second linear regulator, also with an internal FET, regulates the 6 V to a selectable 5-V or 3.3-V MCU I/O voltage.

The TPS65381-Q1 device comprises a linear regulator controller with an external FET and resistor divider that regulates the 6 V to an externally adjustable core voltage of between 0.8 V and 3.3 V.

The device comprises a sensor supply with short-to-ground and short-to-battery protection. Therefore this supply can power a sensor outside the electronic-control unit (ECU).

The device has an integrated charge pump to provide overdrive voltage for the internal regulators. Reverse-battery protection is obtained by using the charge-pump output to control an external NMOS transistor. This solution allows for a lower minimum-battery-voltage operation compared to a traditional reverse-battery blocking diode.

The device monitors undervoltage and overvoltage on all regulator outputs, battery voltage, and internal supply rails. A second bandgap reference, independent from the main bandgap reference, is used for the undervoltage and overvoltage monitoring, to avoid any drifts in the main bandgap reference from being undetected. In addition, regulator current-limits and temperature protections are implemented.

The TPS65381-Q1 has monitoring and protection functions which include the functions as follows: watchdog with trigger and modes, MCU error-signal monitor, clock monitoring on internal oscillators, self-check on the clock monitor, CRC on non-volatile memory, a diagnostic output pin allowing the MCU to observe the internal analog and digital signals of the device, a reset circuit for the MCU, and an enable drive output to disable the safing-path or external power-stages on detected faults. A built-in self-test (BIST) monitors the device functionality at start-up. A dedicated DIAGNOSTIC state allows the MCU to check TPS65381-Q1 monitoring and protection functions.

The TPS65381-Q1 device is offered in a 32-pin HTSSOP PowerPAD package.


  • Qualified for Automotive Applications
  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40°C to +125°C Ambient Operating Temperature
    • Device HBM ESD Classification Level H2
    • Device CDM ESD Classification Level C3B
  • Multi-Rail Power Supply Supporting Among Others
    • Texas Instruments TMS570LS Series Microcontrollers
  • Supply Rails
    • Input voltage range:
      • 5.8 V to 36 V (CAN, I/O, MCU Core, and Sensor-Supply Regulators Functional)
      • 4.5 V to 5.8 V (3.3-V I/O and MCU Core-Voltage Functional)
    • 6-V Asynchronous Switch-Mode Preregulator With Internal FET, 1.3-A Current-Limit, and Temperature Protection
    • 5-V (CAN) Supply Voltage, Linear Regulator With Internal FET, 350-mA Current-Limit, and Temperature Protection
    • 3.3-V or 5-V MCU I/O Voltage, Linear Regulator With Internal FET, 350-mA Current-Limit, and Temperature Protection
    • 0.8-V to 3.3-V Adjustable MCU Core Voltage, Linear Regulator Controller With External FET
    • Sensor Supply: Linear Tracking Regulator With Tracking Input, 100-mA Current-Limit, Temperature Protection, and Protection Against Short to Battery and Short to Ground
    • Charge Pump: Typ. 12 V Above Battery Voltage
  • Power Supply and System Monitoring
    • Independent Undervoltage and Overvoltage Monitoring on All Regulator Outputs, Battery Voltage, and Internal Supplies
    • Independent Bandgap Reference for Voltage Monitoring
    • Independent Voltage References for Regulator References and Voltage Monitoring. Voltage-Monitoring Circuitry With Separate Battery Voltage Input Pin
    • Self-Check on all Voltage Monitoring (During Power-Up and After Power-Up Initiated by External MCU)
    • Junction Temperature Sensing With Shutdown Thresholds
  • Microcontroller Interface
    • Watchdog: Trigger Mode (OPEN/CLOSE Window) or Question and Answer Mode
    • MCU Error-Signal Monitor (Supports TI TMS570 MCU Mode or Other MCUs with PWM Signaling)
    • DIAGNOSTIC State for Performing Device Self-Tests, Diagnostics, and External Interconnect Checks
    • Safe-State for Device and System Protection on Error Event Detection
    • Clock Monitor for Internal Oscillators
    • Self-Tests for Analog- and Digital-Critical Circuits Executed With Every Device Power Up or Activated by MCU in DIAGNOSTIC State
    • CRC on Non-Volatile Memory, Device, and System Configuration Registers
    • Reset circuit for MCU
    • Diagnostic Output Pin Allowing MCU to Observe Internal Analog and Digital Signals of the Device, Selectable Through Multiplexer
  • SPI
    • Configuring IC Registers
    • Watchdog Question-Answering
    • Diagnostic Readout
    • Compliant With 3.3-V and 5-V Logic Levels
  • Enable-Drive Output for Disabling Safing-Path or External Power-Stages on Detected System-Failure
  • Wake-Up Through IGNITION Pin or CAN WAKEUP Pin
  • Package: 32-Pin HTSSOP PowerPAD IC Package

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