Increasing demand for EMI reduction in industrial and automotive devices
Active EMI filter, CISPR 25 Class 5 overall
Lower power solution EMI across the frequency band


As the proportion of electronic components in industrial and automotive applications continues to increase, reducing electromagnetic interference (EMI) is becoming increasingly important, and demand for simpler and more intelligent EMI management functions is also increasing.

Texas Instruments (TI) held an online press conference on the 8th and introduced its support measures and solutions for reducing EMI in next-generation industrial and automotive designs.

“We are developing products that inherently reduce EMI emissions while reducing EMI filter size, enabling developers to reduce system costs and quickly achieve EMI standard requirements,” said Cecelia Smith, vice president and manager of TI’s Boost and Multichannel DC/DC business unit. “This is supported by the WEBENCH® Power Designer EMI simulation tool, comprehensive EMI documentation and EMI performance verification.”

Ganesh Srinivasan, TI Buck Switching RegulatorThe product line manager introduced the 'LM25149-Q1 and LM25149' synchronous DC/DC buck controllers released on the 7th, ▲'LMQ61460' synchronous buck converter (released in December 2020), ▲'TPS25850-Q1' charge port controller (released in October 2020), ▲'LM5157-Q1' asynchronous boost converter (released in March 2021), and ▲'UCC12050' isolated DC/DC converter (released in April 2021).

These products are designed to reduce bill of materials (BOM) and EMI in industrial vehicle applications. Models ending in "Q1" are specifically designed for automotive use.

◇ LM25149-Q1, LM25149 DC/DC buck controller,
Up to 55dBμV EMI reduction with AEF integration and DRSS adoption

Two new synchronous DC/DC buck controllers integrate Active EMI Filter (AEF) and Dual Random Spread Spectrum (DRSS) technology to reduce the footprint of external EMI filters and lower the power solution's conducted EMI across the entire CISPR 25 Class 5 frequency band.

“At a 440kHz switching frequency, solutions using AEF can reduce conducted EMI by up to 50dBμV compared to solutions without AEF and up to 20dBμV compared to solutions using conventional passive filters,” said Srinivasan. “Adding DRSS technology to this can reduce the reduction by an additional 5dBμV in the low- and high-frequency bands.”

Additionally, it adds that the passive EMI filter can reduce its area and volume, allowing for smaller solution sizes while meeting demanding EMI requirements. Interleaved dual-phase operation is possible, and integration of bootstrap diodes, loop compensation circuits, and output voltage feedback elements further increases power density while reducing design complexity and cost. Design optimization is also possible through the use of additional external feedback elements and loop compensation circuits.

The 42-V LM25149-Q1 and LM25149 devices are available in a 3.5-mm × 5.5-mm, 24-pin VQFN package and are available for preproduction on TI.com. Pricing starts at $1.42 and $1.20, respectively, in 1,000-unit quantities. The LM25149-Q1EVM-2100 evaluation module is also available on TI.com for $75, with multiple payment and shipping options available. Volume production is scheduled for Q4 2021, with pin-to-pin compatible 80-V devices also expected.