Bourns Unveils Low Profile Common Mode Chokes with High Current Capacity

Two new series of high current, low profile, surface-mountable devices are suitable to DC power line applications.

 

Bourns SRF1206A and SRF9045A series of common-mode chokes. Image courtesy of Bourns

 

The SRF1206A and SRF9045A series of common-mode chokes offer common mode and also differential mode filtering in one choke configuration. These highly robust products offer high current capacity in a small package to save precious board space, yet can handle up to 80 VDC at 8 amps.

These units are designed to present a high impedance to electromagnetic interference (EMI) over a broad frequency range, purposed to suppress EMI coming into or emerging out of the system covered. 

Both the SRF1206A and SRF9045A series feature separate sector-wound winding configurations. For added strength, the chokes also utilize U-shaped terminals clamped to the core to better handle any mechanical stresses. 

Both series of devices are protected by a plastic shield for a Hi-Pot capability of 500 VAC @ 3 mA for 1 second. Insulation resistance, at 100 VDC, is at a minimum of 10 MΩ.

Bourns is active in the field of common mode chokes, and, along with the two new series, the company offers a wide array of choices.

 

What Are Common Mode Chokes? 

A common mode choke is essentially a transformer. It serves as part of a filtering system proposed to block high frequency noise common to two (or more) power or data lines.

 

Image courtesy of Coilcraft

 

When confronted with common-mode noise, illustrated on the top of the picture, the signals pass in the same direction, producing reinforcing magnetic flux that blocks noise.

The differential power, or data, flowing from the 1 to the 4 port is the equal and opposite of that traveling from the 3 to the 2 port. The magnet fluxes that are produced also equal and opposite, canceling each other out. Thus, a clear path is presented to the desired signals.

 

The SRF1206A Series

There are two members of the SRF1206A series, the SRF1206A-701Y and the SRF1206A-102Y 

	Impedance in Ohms @100MHz		Inductance N1/N2 Ref @100 kHz / 0.1 V	DC resistance N1/N2, Max	Maximum Current
SRF1206A-701Y	500 min	700 typ	9µH	6 milliohms	8 amps
SRF1206A-102Y	750 min	1000 typ	12.5µH	14 milliohms	6 amps

 

The SRF9045A Series

At present there is only one member of the SRF9054A series, the SRF9045A-701Y.

	Impedance in Ohms @100MHz		Inductance N1/N2 Ref @100 kHz / 0.1 V	DC resistance N1/N2, Max	Maximum Current
SRF9045A-701Y	500 min	700 typ	7.5µH	10 milliohms	5 amps

 

Applications

Due to their small size and high current capacity, the SRF1206A and SRF9045A series of common-mode chokes are suited for application in: 

• Switch-mode power supplies
• DC/DC converters
• Power line noise and EMI suppression
• Battery management systems
• Industrial electronics applications

 

Physical and Regulatory Concerns

• The SRF9045A and SRF1206A series are AEC-Q200 compliant
• The devices operate over a temperature ranges of -40 to +125 °C