No more switch-node ringing with TI’s new DC/DC buck regulators

June 28, 2016 // By Christoph Hammerschmidt
Higher power density, operation in deep drop-out conditions and, first of all, elimination of switch-node ringing: These are the benefit that chip vendor Texas Instruments promises to users of TI’s new synchronous buck reulators. The 2.5-A LM53625-Q1 and 3.5-A LM53635-Q1 regulators are designed for high-voltage DC/DC step-down applications such as automotive infotainment, high-end cluster, advanced driver assistance system (ADAS) and body power-supply systems.

Switch node ringing is inherent in all switch-mode power supplies. By reducing parasitic inductance and capacitance in the LM53625-Q1 and LM53635-Q1 regulators, these power solutions lower noise and EMI emissions by up to 15 dB at the system level, which requires less external EMI filtering, saves PCB area and simplifies compliance with CISPR 25 automotive EMI requirements.


LM53625-Q1 and LM53635-Q1 key features and benefits

  • Wide 3.5-V to 42-V operating range handles start-stop and load-dump conditions for 12-V lead acid automotive batteries.
  • Provides up to 93 percent efficiency at 2.1-MHz operation to support compact and high-temperature conditions in automotive applications.
  • Low 18-uA quiescent current (IQ) in standby extends battery life in “always on” applications.
  • Wettable flank packaging enables post-solder optical inspection.
  • Deep drop-out performance of less than 0.6 V under full load and temperature conditions enables compliance with stringent cold-crank and start-stop conditions, saving system cost and solution size.


The LM53625-Q1 and LM53635-Q1 join the recently released LM53600-Q1, LM53601-Q1, LM53602-Q1, LM53603-Q1 and LM5140-Q1 buck converters to create a family of controllers and regulators designed for automotive systems that draw less than 0.65 A of power to more than 10 A. All of these devices feature greater than 2-MHz switching frequency, low operating IQ and EMI reduction features.


The new DC/DC regulators are available in volume now. Offered in a 22-pin, 4-mm-by-5-mm very thin quad flat no-lead (VQFN) package, the LM53625-Q1 is priced at US$2.79 in 1,000-unit quantities and the LM53635-Q1 is priced at US$3.22. Order the LM536253QEVM evaluation module and download a PSpice transient model .


For more information, samples and an evaluation module, see