TPS628502-Q1: TPS628502-Q1: LDO-free RADAR design, how to achieve low-noise and better thermal performance?

Part Number: TPS628502-Q1

Is your LDO-powered RADAR design inefficient and/or getting hot? If you answered yes, you may be interested in a RADAR design that allows for better thermal performance, smaller solution size and lower cost, powered exclusively by DC/DC converters. Importantly, this approach would still allow you to meet radar’s strict noise specifications and avoid causing spurs in the data set.

Some Radar Front End applications can be temperature-sensitive. This means that excessive heat can degrade their performance. We can say: “the more heat, the worse the RADAR performance”. Today, most radar systems are powered by a combination of LDOs and DC/DC converters, sometimes integrated into one power-management IC (PMIC). Recently, we have seen a strong trend towards DC/DC-only power architectures. DC/DC converters offer many advantages for RADAR applications over the traditional approaches:

  1. Improved efficiency and better thermal performance:
    LDOs are known for poor efficiency when the difference between input and output voltage is large. The dissipated LDO heat can have a negative impact on the performance of a radar application. On the other hand, DC/DC measurements show up to 95% efficiency and 50oC lower board temperature vs LDO.
  2. Lower noise, reduced solution size and cost:
    - Latest DC/DC converters have similar noise levels as LDOs.
    - Total DC/DC solution size is in the 40 mm2 range, which is similar to the size of an LDO solution.
    Keep in mind that DC/DC converters need Cin, Cout and an inductor but LDOs only need Cin and Cout.

Late last year we helped a leading automotive radar customer build a reference design to power TI’s Radar AWR16xx/18xx, based on the LP87702-Q1 PMIC and new TPS628501-Q1 1A DC/DC buck converter in the smallest SOT583 package (1.6 mm by 2.1 mm). Customers that do not require ASIL can also consider using discrete components.