The LMR36506-Q1 from Texas Instruments is an easy-to-use synchronous buck converter. It’s a DC/DC converter that steps or brings down voltage from the supply or input to the load or input. It may be the smallest step-down DC-to-DC converter, but it’s packed with a lot of features and functions. The LMR36506-Q1 is capable of handling up to 70V of input voltage transients, which helps automotive applications address crank start impulses.

What is a Buck Converter?

A buck or step-down converter is a power converter or DC-to-DC switch mode power supply that lowers or “bucks” an unregulated DC supply’s input voltage. A buck converter is known for its over-95% efficiency rate. As such, it is also the ideal option for when you need to switch the main supply voltage of your computer to a lower voltage. 

Buck converters get inputs straight from batteries and other DC sources. They can also source direct current from AC lines using a rectifier capacitor circuit. 

How a Buck Converter Works

There are two steps involved in how buck converters work:

  1. Switch on – Turning the switch on will allow the current to flow all the way through to the capacitor. This results to an automatic charge. The charging current has limits and capacitor rise does not happen instantly. It cannot immediately reach its peak value.
  2. Switch off – It is not possible for the inductor current to change in an instant, so a voltage is created across it – courtesy of the inductor. Through the diode, the voltage then powers the load and charges the capacitor. As such, current output is steady all throughout the switching process.

In summary, in buck or step-down converters; switching on results to a zero voltage drop for the diode and switch, while there is no current flow when switching off. 

Buck converters operate in two ways: continuous mode and discontinuous mode -

  • In continuous mode, the current does not drop to zero throughout the entire cycle. 
  • In discontinuous mode, the opposite happens – the inductor goes down to zero in one part of the communication cycle.

LMR36506-Q1 Applications and Features

The following are the applications and features of the LMR36506-Q1 buck or step-down DC-to-DC converter:


  • ADAs or advanced driver assistance systems – an interactive system that is intended to help create a safe and convenient automated driving experience (for driver monitoring, imaging radar, automotive thermal camera, and park assist sensor)
  • Automotive infotainment and entertainment systems – interactive systems that help produce high-quality in-vehicle infotainment and entertainment (i.e., smart device integration, digital cockpit controllers, audio amplifiers, and telematics)
  • Body electronics & lighting – automotive body electronics & lighting needs, such as adaptive headlights, car access systems, heating & cooling, automotive gateway, power seats, and body sensors


  • AEC-Q100-qualified (for automotive applications)
  • -40°C to +125°C TA temperature grade 1
  • 0V to 65V extensive range of input voltage
  • Highly efficient (over 80% at 1mA)
  • Internal compensation
  • HotRod package (2-mm x 2-mm)
  • Different options for fixed output voltage; it is also adjustable
  • Functional safety system design
  • LMR36503-Q1 pin compatible