Automotive switching regulators

OPTIREG™ switcher buck, boost, and buck-boost DC-DC converters: from 4.75 V to 45 V, qualified to AEC-Q100 for automotive ECU designs

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Overview

Automotive switching regulators are integrated into a wide range of vehicle systems, from body control modules and ADAS to infotainment and powertrain applications. As ECU designs become more complex and power-dense, demand for robust, high-quality automotive switcher ICs with wide input voltage range and integrated protection continues to grow.

Key Features

  • Highly efficient and robust
  • Designed for harsh climates
  • Low-energy consumption
  • Diverse configurations available
  • Wide voltage output range
  • Current and voltage regulation
  • Flexible switching range
  • Overvoltage/undervoltage protection
  • Green products: RoHS-compliant

Products

About

Buck, boost, and buck-boost automotive switching regulators

OPTIREG™ automotive switching regulators are DC-DC converter ICs that convert an unregulated input voltage into a stabilized output voltage for use in automotive electronic control units (ECUs). 

Infineon's OPTIREG™ switcher family is organized into three converter types: 

  • buck converters (step-down, with integrated power stage)
  • boost controllers (step-up, with external switches) 
  • buck-boost converters (step-up/step-down)

The family sits within the broader OPTIREG™ automotive power supply IC portfolio alongside OPTIREG™ linear, OPTIREG™ multiphase, and OPTIREG™ SBC product lines.

Automotive power supply IC portfolio

Key design benefits of OPTIREG™ automotive switching regulators

  • Wide input voltage range for harsh board-net environments 

OPTIREG™ automotive switching regulators are designed to maintain stable output regulation across the transient-heavy conditions of automotive board-net environments, including load dump, cold-crank, and voltage spikes. Input voltage range varies by device; confirm the specific product datasheet for your application.

  • Integrated OV/UV protection reduces external component count 

Overvoltage and undervoltage monitoring are integrated on-chip, eliminating the need for discrete protection components and reducing BOM complexity in ECU power supply designs.

  • Low quiescent current for ECU low-power modes 

The TLS412x family achieves a quiescent current below 31 µA, enabling efficient operation during ECU standby and sleep states and extending battery life in low-power modes.

  • Flexible switching frequency for EMI and efficiency optimization 

The adjustable switching frequency ranges from approximately 320 kHz to 2.8 MHz across the OPTIREG™ switcher family, enabling optimization of efficiency, solution size, and EMI per application. Switching frequency varies by device; confirm the product datasheet before designing in.

Input voltage, output voltage, switching frequency, and IQ

Input voltage range (VIN): The input voltage range defines the board-net conditions the regulator can handle. OPTIREG™ automotive switching regulators cover 4.7 V to 45 V across the device family, providing tolerance to automotive transients such as cold-crank and load dump. VIN range varies by device; confirm the specific product datasheet for your application.

Output voltage (VOUT): OPTIREG™ buck converters support fixed output voltages of 5 V and 3.3 V, as well as an adjustable output option, covering the supply rails required by automotive microcontrollers and digital loads.

Switching frequency (fSW): Switching frequency determines the trade-off between efficiency, inductor size, and EMI. The TLS412x buck converter family supports an adjustable switching frequency from 320 kHz to 2.8 MHz. The TLF51801ELV buck controller operates from 100 kHz to 700 kHz with external clock synchronization support.

Quiescent current (IQ): Quiescent current is the supply current drawn when the regulator output is in regulation with no load. The TLS412x family achieves IQ below 31 µA, directly reducing power consumption during ECU low-power and standby modes.

Protection, thermal performance, and automotive qualification data

  • Overvoltage and undervoltage protection 

Integrated OV and UV monitoring activates under fault conditions to protect the downstream load and the regulator itself. Protection response is handled on-chip with no external supervisory components required, maintaining system integrity across the full -40°C to +150°C operating temperature range.

  • Thermal performance

The TLS4120, TLS4125, and TLF51801ELV are rated to a maximum junction temperature (Tj max) of 150°C.

  • Automotive qualification 

OPTIREG™ automotive switching regulators are qualified to AEC-Q100 Grade 0 and Grade 1, covering an operating temperature range of -40°C to +150°C, meeting the robustness requirements of automotive ECU power supply designs.

  • RoHS compliance

All OPTIREG™ green products are RoHS-compliant, meeting global standards for environmental safety.

More about AEC-Q100

ECU power supply: Body, ADAS, infotainment, and powertrain

Body and comfort ECUs (BCM, gateway, cluster)

For body control modules, gateway ECUs, and instrument clusters requiring a stable 5V or 3.3V rail from a 12V board-net, the OPTIREG™ buck converter (e.g. TLS4120D0EP V33, TLS4125D0EP V50) is recommended for its integrated power stage and low quiescent current. 

ADAS, camera, radar, and telematics

For camera pre-regulators, radar supply rails, and telematics modules, the OPTIREG™ buck controller (TLF51801ELV) supports loads up to 10A with an adjustable, externally synchronizable switching frequency, enabling EMI-optimized designs.

Infotainment, display, and dashboard

Buck converters and buck controllers in the OPTIREG™ family support display, car-media, and high-end cluster supply rails where compact solution size and low noise are required.

Cold-cranking and 48V powertrain pre-regulation

The OPTIREG™ boost controller (TLE8386-2EL) supports cold-cranking, GDI and piezo injection, and 48V flyback topologies for 12V-to-12V conversion in start-stop and mild-hybrid powertrain applications.

Automotive applications overview

Step-by-step OPTIREG™ switching regulator selection guide

Step 1: Determine converter topology

Select a buck converter if the output voltage is lower than the input. Select a boost controller if the output voltage must exceed the input. Select a buck-boost converter if the output voltage may be higher or lower than the input, or of inverted polarity.

Step 2: Identify integration requirement

If an integrated power stage is preferred (lower external component count), select a buck converter IC (e.g. TLS4120D0EP, TLF50251EL). If external power switches are required for loads above the integrated device rating, select a buck controller (TLF51801ELV, up to 10A).

Step 3: Confirm output voltage

OPTIREG™ buck converters support 5 V and 3.3 V fixed outputs and an adjustable option. Match the required supply rail to the available fixed output or use the adjustable variant.

Step 4: Evaluate switching frequency requirements

If the design requires synchronization to an external clock (e.g. to avoid interference with RF or radar), select the TLF51801ELV buck controller, which supports external clock synchronization.

Use the OPTIREG™ parametric selection tool to filter by topology, output voltage, and package.

Go to parametric selection tool

Automotive smart power longevity and RoHS-compliant portfolio

Automotive longevity program

Infineon’s Automotive longevity program provides a long-term product availability commitment for OPTIREG™ switchers, reducing redesign risk for automotive programs with multi-year production lifecycles. Find out more about the Automotive Smart Power longevity program.

AEC-Q100 qualified

OPTIREG™ automotive switching regulators are qualified to AEC-Q100, meeting the robustness and reliability requirements of automotive ECU power supply designs across the full −40 °C to +150 °C operating range.

RoHS compliance

All OPTIREG™ green products are RoHS-compliant and meet global standards for environmental safety.

Infineon automotive longevity program

Software, simulation models, tools, and training for OPTIREG™

  • Software, SDKs & tools

Infineon Designer provides an online simulation environment for OPTIREG™ automotive switching regulators, combining analog (SPICE) and digital (MCU) simulation in a single prototyping engine. PLECS stability and efficiency simulations are available for the TLS4120 and TLS4125 families, enabling prediction of power loss and junction temperature at user-defined electrical conditions without requiring hardware.

  • SPICE models & simulation files

Spice models are available for download for the TLS4120 and TLS4125 device families, supporting circuit-level simulation and timing margin estimation before hardware build.

  • Training videos

Six training videos are available via the Infineon Academy learning platform (free of charge, available in EN, JA, and CN), covering OPTIREG™ switcher design-in, the TLS412x family overview, ADAS/AD power supply trends, powertrain electrification, and automotive application breadth.

More about Infineon design-in resources
SPICE models & simulations

Buck, boost, and buck-boost automotive switching regulators

OPTIREG™ automotive switching regulators are DC-DC converter ICs that convert an unregulated input voltage into a stabilized output voltage for use in automotive electronic control units (ECUs). 

Infineon's OPTIREG™ switcher family is organized into three converter types: 

  • buck converters (step-down, with integrated power stage)
  • boost controllers (step-up, with external switches) 
  • buck-boost converters (step-up/step-down)

The family sits within the broader OPTIREG™ automotive power supply IC portfolio alongside OPTIREG™ linear, OPTIREG™ multiphase, and OPTIREG™ SBC product lines.

Automotive power supply IC portfolio

Key design benefits of OPTIREG™ automotive switching regulators

  • Wide input voltage range for harsh board-net environments 

OPTIREG™ automotive switching regulators are designed to maintain stable output regulation across the transient-heavy conditions of automotive board-net environments, including load dump, cold-crank, and voltage spikes. Input voltage range varies by device; confirm the specific product datasheet for your application.

  • Integrated OV/UV protection reduces external component count 

Overvoltage and undervoltage monitoring are integrated on-chip, eliminating the need for discrete protection components and reducing BOM complexity in ECU power supply designs.

  • Low quiescent current for ECU low-power modes 

The TLS412x family achieves a quiescent current below 31 µA, enabling efficient operation during ECU standby and sleep states and extending battery life in low-power modes.

  • Flexible switching frequency for EMI and efficiency optimization 

The adjustable switching frequency ranges from approximately 320 kHz to 2.8 MHz across the OPTIREG™ switcher family, enabling optimization of efficiency, solution size, and EMI per application. Switching frequency varies by device; confirm the product datasheet before designing in.

Input voltage, output voltage, switching frequency, and IQ

Input voltage range (VIN): The input voltage range defines the board-net conditions the regulator can handle. OPTIREG™ automotive switching regulators cover 4.7 V to 45 V across the device family, providing tolerance to automotive transients such as cold-crank and load dump. VIN range varies by device; confirm the specific product datasheet for your application.

Output voltage (VOUT): OPTIREG™ buck converters support fixed output voltages of 5 V and 3.3 V, as well as an adjustable output option, covering the supply rails required by automotive microcontrollers and digital loads.

Switching frequency (fSW): Switching frequency determines the trade-off between efficiency, inductor size, and EMI. The TLS412x buck converter family supports an adjustable switching frequency from 320 kHz to 2.8 MHz. The TLF51801ELV buck controller operates from 100 kHz to 700 kHz with external clock synchronization support.

Quiescent current (IQ): Quiescent current is the supply current drawn when the regulator output is in regulation with no load. The TLS412x family achieves IQ below 31 µA, directly reducing power consumption during ECU low-power and standby modes.

Protection, thermal performance, and automotive qualification data

  • Overvoltage and undervoltage protection 

Integrated OV and UV monitoring activates under fault conditions to protect the downstream load and the regulator itself. Protection response is handled on-chip with no external supervisory components required, maintaining system integrity across the full -40°C to +150°C operating temperature range.

  • Thermal performance

The TLS4120, TLS4125, and TLF51801ELV are rated to a maximum junction temperature (Tj max) of 150°C.

  • Automotive qualification 

OPTIREG™ automotive switching regulators are qualified to AEC-Q100 Grade 0 and Grade 1, covering an operating temperature range of -40°C to +150°C, meeting the robustness requirements of automotive ECU power supply designs.

  • RoHS compliance

All OPTIREG™ green products are RoHS-compliant, meeting global standards for environmental safety.

More about AEC-Q100

ECU power supply: Body, ADAS, infotainment, and powertrain

Body and comfort ECUs (BCM, gateway, cluster)

For body control modules, gateway ECUs, and instrument clusters requiring a stable 5V or 3.3V rail from a 12V board-net, the OPTIREG™ buck converter (e.g. TLS4120D0EP V33, TLS4125D0EP V50) is recommended for its integrated power stage and low quiescent current. 

ADAS, camera, radar, and telematics

For camera pre-regulators, radar supply rails, and telematics modules, the OPTIREG™ buck controller (TLF51801ELV) supports loads up to 10A with an adjustable, externally synchronizable switching frequency, enabling EMI-optimized designs.

Infotainment, display, and dashboard

Buck converters and buck controllers in the OPTIREG™ family support display, car-media, and high-end cluster supply rails where compact solution size and low noise are required.

Cold-cranking and 48V powertrain pre-regulation

The OPTIREG™ boost controller (TLE8386-2EL) supports cold-cranking, GDI and piezo injection, and 48V flyback topologies for 12V-to-12V conversion in start-stop and mild-hybrid powertrain applications.

Automotive applications overview

Step-by-step OPTIREG™ switching regulator selection guide

Step 1: Determine converter topology

Select a buck converter if the output voltage is lower than the input. Select a boost controller if the output voltage must exceed the input. Select a buck-boost converter if the output voltage may be higher or lower than the input, or of inverted polarity.

Step 2: Identify integration requirement

If an integrated power stage is preferred (lower external component count), select a buck converter IC (e.g. TLS4120D0EP, TLF50251EL). If external power switches are required for loads above the integrated device rating, select a buck controller (TLF51801ELV, up to 10A).

Step 3: Confirm output voltage

OPTIREG™ buck converters support 5 V and 3.3 V fixed outputs and an adjustable option. Match the required supply rail to the available fixed output or use the adjustable variant.

Step 4: Evaluate switching frequency requirements

If the design requires synchronization to an external clock (e.g. to avoid interference with RF or radar), select the TLF51801ELV buck controller, which supports external clock synchronization.

Use the OPTIREG™ parametric selection tool to filter by topology, output voltage, and package.

Go to parametric selection tool

Automotive smart power longevity and RoHS-compliant portfolio

Automotive longevity program

Infineon’s Automotive longevity program provides a long-term product availability commitment for OPTIREG™ switchers, reducing redesign risk for automotive programs with multi-year production lifecycles. Find out more about the Automotive Smart Power longevity program.

AEC-Q100 qualified

OPTIREG™ automotive switching regulators are qualified to AEC-Q100, meeting the robustness and reliability requirements of automotive ECU power supply designs across the full −40 °C to +150 °C operating range.

RoHS compliance

All OPTIREG™ green products are RoHS-compliant and meet global standards for environmental safety.

Infineon automotive longevity program

Software, simulation models, tools, and training for OPTIREG™

  • Software, SDKs & tools

Infineon Designer provides an online simulation environment for OPTIREG™ automotive switching regulators, combining analog (SPICE) and digital (MCU) simulation in a single prototyping engine. PLECS stability and efficiency simulations are available for the TLS4120 and TLS4125 families, enabling prediction of power loss and junction temperature at user-defined electrical conditions without requiring hardware.

  • SPICE models & simulation files

Spice models are available for download for the TLS4120 and TLS4125 device families, supporting circuit-level simulation and timing margin estimation before hardware build.

  • Training videos

Six training videos are available via the Infineon Academy learning platform (free of charge, available in EN, JA, and CN), covering OPTIREG™ switcher design-in, the TLS412x family overview, ADAS/AD power supply trends, powertrain electrification, and automotive application breadth.

More about Infineon design-in resources
SPICE models & simulations
Documents

Design resources

Developer community