STMicroelectronics launches new EMI filters for automotive applications: First CMF with automotive-grade qualification

STMicroelectronics recently announced ECMF04-4HSM10Y and ECMF04-4HSWM10Y automotive-qualified common-mode filters (CMF) for high-speed serial buses protect interface ICs by integrating transient-suppression diodes with low clamping voltage. Christian Beia, Product Marketing Manager, STMicroelectronics spoke to EM more about this product and its features.

Christian Beia, Product Marketing Manager, STMicroelectronics

1.            Please highlight more about this announcement.

STMicroelectronics recently announced that it has Integrated Common-Mode Filter and ESD Suppression in New Automotive-Protection Devices. The ECMF04-4HSM10Y and ECMF04-4HSWM10Y automotive-qualified common-mode filters (CMF) for high-speed serial buses protect interface ICs by integrating transient-suppression diodes with low clamping voltage. These are the first CMFs on the market with automotive-grade qualification and automotive surge compliance guaranteed. They are not only produced and qualified according to AEC-Q101 requirements but are also designed and tested against automotive surge specifics such as ISO10605.

 2.           What are the new features?

The SRK1000A / SRK1000B are synchronous rectification devices that allow easy design of flyback converters with the highest efficiency by strongly reducing conduction losses.

Uniquely, the SRK1000A/B adjusts to manage different loading conditions of the converter with the same ability to minimize losses.

Housed in a small SOT23 6-pin package, the STK1000A/B is very easy to configure and needs minimal external components. Fast turn-on, with minimum delay, and innovative adaptive turn-off logic, maximizes synchronous-rectification MOSFET conduction time and minimizes parasitics. Competitive devices require external compensation of stray parasitic inductance, while the SRK1000A/B does not need any external circuit, optimizing the subsystem BOM.

 3.           Share key applications of the device.

The STK1000A / SRK1000B synchronous rectification devices are ideal for flyback switched-mode power supplies operating in QR mode and mixed CCM/DCM, ranging from 15W to 90W, e.g:

  • AC/DC Adapters
  • Battery Chargers
  • Quick chargers
  • USB power delivery (profile 3, 4, 5)

 4.           What are the competitive advantages of the ST device?

The competitive advantage of the SRK1000A/B includes the adaptive turn-off mechanism, which assures the SRK1000A/B deliver higher efficiency. In addition, the STK1000A/B do not require external compensation for stray parasitic inductance, which eliminates some external components and lowers the BoM.

5.            How does the SRK1000A/B manage its low power modes?

The SRK1000A/B efficiently manages low power modes using its ability to detect low power conditions and enter in low consumption mode at light load. At light load, the synchronous rectification is no longer beneficial since the switching losses would negatively affect the efficiency.

 The SRK1000A/B detects light load conditions when either the primary-side controller starts working in burst-mode operation or the synchronous rectification MOSFET conduction time drops below the programmed minimum, TON.

When either of these conditions happen, the SRK1000A/B stops the switching activity, turning OFF the synchronous rectification MOSFET and entering into a deep sleep mode where quiescent current drops below 160uA.

 Many applications can benefit from low-power mode including battery chargers when battery is fully charged, power supplies when put in standby, AC/DC adapters when left connected to the mains with no device connected. 

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