EMC Filters

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EMC Filters

 

EMC filter is designed to improve the EMC performance of a power supply. Depending on the type of filter, the filter can either improve the overall EMC performance of a power supply to meet certain standards or improve only the immunity against the specific type of electromagnetic interference. EMC filter for power supply usually consists of capacitors and inductors to form an LC circuit.

                  In this application note, we will cover the topics of how to select an EMC filter, and how to connect an EMC filter.

 

1        How to select an EMC filter

1.1         Confirm EMC filter Specification.

We can categorize the EMC filter into three different types: AC EMC filter, DC EMC filter, and Common mode choke.

The below diagram shows the Aimtec EMC filter line up.

 

 

Figure 1. Aimtec EMC filter offering

1.2         Select the proper device type.

EMC includes EMI and EMS. EMI stands for electromagnetic interference. EMS stands for electromagnetic susceptibility which indicates the ability of a power supply to withstand electromagnetic interference. EMI filter can reduce the electromagnetic interference emitting from the power supply. Choose the EMI filter if only need to deal with electromagnetic interference. Choose the EMC filter if both electromagnetic interference and electromagnetic susceptibility need to be improved. If the power supply needs to be able to handle excessive noise at a certain frequency, then follow the attenuation graph and choose the corresponding common mode choke.

 

Figure 2. Common mode choke frequency attenuation

 

1.3         Confirm the input power source.

Base on the input power source, the EMC filter can be separated into AC and DC EMC filters.

 

1.4         Confirm the input voltage range.

After confirming the input power source, select a filter with proper input voltage range which covers the input voltage range of the power supply.

 

1.5         Confirm the input current or power.

EMC filter includes active filters and passive filters. The active filter includes active components such as MOSFET, hence the power rating and the operating voltage range of the device must be considered. The operating voltage and the converter power rating must not exceed the maximum allowable voltage and power rating of the filter. For passive filter, it includes only passive components such as differential mode choke or common mode choke. The input voltage and current must be considered when selecting a passive filter. The input voltage and input current must not exceed the filter’s rating. Figure 3 and 4 show the block diagrams of the active filters and passive filters.

 

Figure 3. Passive filter

 

 

2        How to connect an EMC filter

After picking the right type of filter, the next step is to decide how and where to connect the filter. Follow the general guidelines of connecting the EMC filter below to ensure the filter works properly.

 

2.1         If both EMS and EMI filter is used, make sure the EMS filter is placed before the EMI filter.

 

 

Figure 5. Correct EMS and EMI filter placement

 

2.2         In general, the EMC filter comes with input, output, and ground pins. Ground the EMC filter properly to ensure the filter works properly.

The ground pin cannot be shorted to the input or output. Below are the examples of incorrect ground pin connection.

 

 

Figure 6. Incorrect ground pin connection example

 

 

Figure 7. Incorrect ground pin connection example

 

 

Figure 8. Incorrect ground pin connection example

 

 

 

2.3         The ground pin of the EMC filter must be connected to the chassis ground and the wire must be as short as possible. 

 

2.4         When placing the EMC filter inside a shell or case, place the filter close to the shell or case to maximize the filtering effect.

 

 

Figure 11. Proper EMC filter placement example

 

Below are examples of improper EMC filter placement. Having the EMC filter away from the case or having the output wire come close to the unfiltered input end will reduce the filtering effect and cause the interference to enter the case without going through the filter.

 

 

2.5         Application Circuit   

In addition to the EMC filter, the application circuit specified in the datasheet must be added to the circuit. Failure to follow the application circuit will affect the EMC performance and not able to meet the EMC standard.

The below example shows the application circuit for AMFW110-0.9NZ filter with an Aimtec DC/DC converter.  

 

Figure 14. AMFW110-0.9NZ application circuit

AC EMC Filter Supporting Models

 

AMFE30503

Model

AMEOF1-JZ, AMEOF3-BJZ, AMEOF3-JZ, AMEOF5-JZ

EMI (Without External Circuit)

NA

EMI (With AMFE30503-LN11)

CISPR32/EN55032 CLASS B

EFT (Without External Circuit)

NA

EFT (With AMFE30503-LN11)

IEC/EN61000-4-4 ± 4KV Perf. Criteria B

Surge (Without External Circuit)

NA

Surge (With AMFE30503-LN11)

IEC/EN61000-4-5 ± 1KV / ± 2KV Perf. Criteria B

 

 

AMFE305150

Model

AME1-JZ
AME2-JZ

AME3-CJZ

AMEL5-CJZ

AMEL5-JZ

AMEL10-MJZ

AMEL12-CJZ
AMEL20-CJZ

AME5-CJZ
AME5-JZ
AME10-CJZ
AME10-JZ
AME15-CJZ
AME15-JZ
AME15-MJZ
AME20-CJZ
AME20-JZ
AME25-CJZ
AME25-JZ
AME25-MJZ
AME40-CJZ
AME40-MJZ
AME60-MJZ

EMI (Without External Circuit)

CISPR32/EN55032 Class B

CISPR32/EN55032 Class A

CISPR32/EN55032 Class A

CISPR32/EN55032 Class B

CISPR32/EN55032 Class A

CISPR32/EN55032 Class B

CISPR32/EN55032 Class B

EMI (With EMC filter)

 

CISPR32/EN55032 Class B

CISPR32/EN55032 Class B

 

CISPR32/EN55032 Class B

   

EFT (Without External Circuit)

   

IEC/EN61000-4-4 ± 2KV

IEC/EN61000-4-4 ± 2KV

IEC/EN61000-4-4 ± 2KV

IEC/EN61000-4-4 ± 4KV

IEC/EN61000-4-4 ± 2KV

EFT (With EMC filter)

IEC/EN61000-4-4 ± 2KV

IEC/EN61000-4-4 ± 2KV

IEC/EN61000-4-4 ± 4KV

IEC/EN61000-4-4 ± 4KV

IEC/EN61000-4-4 ± 4KV

 

IEC/EN61000-4-4 ± 4KV

Surge (Without External Circuit)

   

IEC/EN61000-4-5 ± 1KV / ± 2KV

IEC/EN61000-4-5 ± 1KV

IEC/EN61000-4-5 ± 1KV

IEC/EN61000-4-5 ± 2KV

IEC/EN61000-4-5 ± 1KV / ± 2KV

Surge (With AMFE305150-LN22)

IEC/EN61000-4-5 ± 1KV / ± 2KV

IEC/EN61000-4-5 ± 1KV / ± 2KV

IEC/EN61000-4-4 ± 2KV / ± 4KV

IEC/EN61000-4-4 ± 2KV / ± 4KV

IEC/EN61000-4-4 ± 2KV / ± 4KV

 

IEC/EN61000-4-4 ± 2KV / ± 4KV

Surge (With AMFE305150-LN42)

         

IEC/EN61000-4-4 ± 4KV / ± 6KV

 

 

 

 

 

 

 

 

 

 

 

 

Active DC EMC Filter Supporting Models

 

AMFW48-0.625NZ

Model

AM10CW-NZ 48Vin

AM10EW-NZ 48Vin

AM10T-NZ 24,48Vin

AM10TW-NZ 48Vin

AM10C-NZ 24Vin

AM10C-NZ 48Vin

AM10G-NZ 24Vin

EMI (Without external circuit)

EN55032, Class A

EN55032, Class A

EN55032, Class A

EN55032, Class A

EN55032, Class A

NA

NA

EMI (With AMFW48-0.625NZ)

EN55032, Class B

ESD (Without external circuit)

IEC 61000-4-2 Contact ±4KV, Criteria B

IEC 61000-4-2 Contact ±4KV, Criteria B

IEC 61000-4-2 Contact ±4KV, Criteria B

IEC 61000-4-2 Contact ±4KV, Criteria B

IEC 61000-4-2 Contact ±4KV, Criteria B

IEC 61000-4-2 Contact ±4KV, Criteria B

IEC 61000-4-2 Contact ±6KV, Criteria B

ESD (With AMFW48-0.625NZ)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

RS (Without external circuit)

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

RS (With AMFW48-0.625NZ)

IEC 61000-4-3 10V/m, Criteria A

EFT (Without external circuit)

NA

NA

NA

NA

NA

NA

NA

EFT (With AMFW48-0.625NZ)

IEC 61000-4-4 ±4KV,Criteria B

Surge (Without external circuit)

NA

NA

NA

NA

NA

NA

NA

Surge (With AMFW48-0.625NZ)

IEC 61000-4-5 ±2KV /±4KV, Criteria B

CS (Without external circuit)

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 10Vr.m.s., Criteria A

IEC61000-4-6 10Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

CS (With AMFW48-0.625NZ)

IEC 61000-4-6 10Vr.m.s, Criteria A

Voltage dip (Without external circuit)

IEC61000-4-29 0% 70%., Criteria B

IEC61000-4-29 0% 70%., Criteria B

IEC61000-4-29 0% 70%., Criteria B

IEC61000-4-29 0% 70%., Criteria B

NA

NA

NA

Voltage dip (With AMFW48-0.625NZ)

NA

 

 

AMFW48-0.625NZ

Model

AM15C-NZ

24, 48Vin

AM15CW-NZ 48Vin

AM15E-NZ 24,48Vin

AM15OW-NZ 48Vin

AM20CW-NZ 48Vin

AM20E-NZ 24,48Vin

AM20EW-NZ 48Vin

EMI (Without external circuit)

EN55032, Class A

EN55032, Class A

EN55032, Class A

NA

NA

EN55032, Class A

EN55032, Class A

EMI (With AMFW48-0.625NZ)

EN55032, Class B

ESD (Without external circuit)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

IEC 61000-4-2 Contact ±4KV, Criteria B

IEC 61000-4-2 Contact ±6KV, Criteria B

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

IEC 61000-4-2 Contact ±4KV, Criteria B

IEC 61000-4-2 Contact ±4KV, Criteria B

ESD (With AMFW48-0.625NZ)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

RS (Without external circuit)

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

RS (With AMFW48-0.625NZ)

IEC 61000-4-3 10V/m, Criteria A

EFT (Without external circuit)

NA

NA

NA

NA

NA

NA

NA

EFT (With AMFW48-0.625NZ)

IEC 61000-4-4 ±4KV,Criteria B

Surge (Without external circuit)

NA

NA

NA

NA

NA

NA

NA

Surge (With AMFW48-0.625NZ)

IEC 61000-4-5 ±2KV /±4KV, Criteria B

CS (Without external circuit)

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

IEC61000-4-6 3Vr.m.s., Criteria A

CS (With AMFW48-0.625NZ)

IEC 61000-4-6 10Vr.m.s, Criteria A

Voltage dip (Without external circuit)

NA

NA

IEC61000-4-29 0% 70%., Criteria B

NA

NA

IEC61000-4-29 0% 70%., Criteria B

IEC61000-4-29 0% 70%., Criteria B

Voltage dip (With AMFW48-0.625NZ)

NA

 

AMF24-2NZ

Model

AM50E-NZ 24Vin

EMI (Without external circuit)

NA

EMI (With AMFW24-1.25NZ)

EN55032, class B

ESD (Without external circuit)

IEC 61000-4-2 Contact ±4KV, Criteria B

ESD (With AMFW24-1.25NZ)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

RS (Without external circuit)

IEC61000-4-3 10V/m,  Criteria A

RS (With AMFW24-1.25NZ)

IEC 61000-4-3 10V/m, Criteria A

EFT (Without external circuit)

NA

EFT (With AMFW24-1.25NZ)

IEC 61000-4-4 ±4KV,Criteria B

Surge (Without external circuit)

NA

Surge (With AMFW24-1.25NZ)

IEC 61000-4-5 ±2KV /±4KV, Criteria B

CS (Without external circuit)

IEC61000-4-6 3Vr.m.s., Criteria A

CS (With AMFW24-1.25NZ)

IEC 61000-4-6 10Vr.m.s, Criteria A

Voltage dip (Without external circuit)

NA

Voltage dip (With AMFW24-1.25NZ)

NA

 

 

AMF48-1.5NZ

Model

AM50E-NZ 48Vin

EMI (Without external circuit)

EN55032, class B

EMI (With AMFW48-0.625NZ)

EN55032, Class B

ESD (Without external circuit)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

ESD (With AMFW48-0.625NZ)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

RS (Without external circuit)

IEC 61000-4-3 10V/m, Criteria A

RS (With AMFW48-0.625NZ)

IEC 61000-4-3 10V/m, Criteria A

EFT (Without external circuit)

IEC 61000-4-4 ±4KV,Criteria B

EFT (With AMFW48-0.625NZ)

IEC 61000-4-4 ±4KV,Criteria B

Surge (Without external circuit)

IEC 61000-4-5 ±2KV /±4KV, Criteria B

Surge (With AMFW48-0.625NZ)

IEC 61000-4-5 ±2KV /±4KV, Criteria B

CS (Without external circuit)

IEC 61000-4-6 10Vr.m.s, Criteria A

CS (With AMFW48-0.625NZ)

IEC 61000-4-6 10Vr.m.s, Criteria A

Voltage dip (Without external circuit)

NA

Voltage dip (With AMFW48-0.625NZ)

NA

 

 

 

AMFW72-0.41NZ

Model

AM10EW-NZ 110Vin

AM15EW-NZ 110Vin

AM20EW-NZ 110Vin

EMI (Without external circuit)

EN55032, Class A

NA

NA

EMI (With AMFW72-0.41NZ)

EN55032, Class B

ESD (Without external circuit)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

ESD (With AMFW72-0.41NZ)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

RS (Without external circuit)

IEC61000-4-3 20V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

RS (With AMFW72-0.41NZ)

IEC 61000-4-3 10V/m, Criteria A

EFT (Without external circuit)

NA

NA

NA

EFT (With AMFW72-0.41NZ)

IEC 61000-4-4 ±4KV,Criteria B

Surge (Without external circuit)

NA

NA

NA

Surge (With AMFW72-0.41NZ)

IEC 61000-4-5 ±2KV /±4KV, Criteria B

CS (Without external circuit)

IEC 61000-4-6 10Vr.m.s, Criteria A

IEC 61000-4-6 10Vr.m.s, Criteria A

IEC 61000-4-6 10Vr.m.s, Criteria A

CS (With AMFW72-0.41NZ)

IEC 61000-4-6 10Vr.m.s, Criteria A

Voltage dip (Without external circuit)

NA

NA

NA

Voltage dip (With AMFW72-0.41NZ)

NA

 

AMFW72-0.69NZ

Model

AM40EW-NZ 110Vin

EMI(Without external circuit)

NA

EMI(With AMFW72-0.69NZ)

EN55032, Class B

ESD(Without external circuit)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

ESD(With AMFW72-0.69NZ)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

RS(Without external circuit)

IEC61000-4-3 20V/m,  Criteria A

RS(With AMFW72-0.69NZ)

IEC 61000-4-3 10V/m, Criteria A

EFT(Without external circuit)

NA

EFT(With AMFW72-0.69NZ)

IEC 61000-4-4 ±4KV,Criteria B

Surge(Without external circuit)

NA

Surge(With AMFW72-0.69NZ)

IEC 61000-4-5 ±2KV /±4KV, Criteria B

CS(Without external circuit)

IEC 61000-4-6 10Vr.m.s, Criteria A

CS(With AMFW72-0.69NZ)

IEC 61000-4-6 10Vr.m.s, Criteria A

Voltage dip(Without external circuit)

NA

Voltage dip(With AMFW72-0.69NZ)

NA

 

AMFW72-13NZ

Model

AM6CW-NZ 110Vin

EMI (Without external circuit)

NA

EMI (With AMFW72-13NZ)

EN55032, Class B

ESD (Without external circuit)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

ESD (With AMFW72-13NZ)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

RS (Without external circuit)

IEC61000-4-3 20V/m,  Criteria A

RS (With AMFW72-13NZ)

IEC 61000-4-3 10V/m, Criteria A

EFT (Without external circuit)

NA

EFT (With AMFW72-13NZ)

IEC 61000-4-4 ±4KV,Criteria B

Surge (Without external circuit)

NA

Surge (With AMFW72-13NZ)

IEC 61000-4-5 ±2KV /±4KV, Criteria B

CS (Without external circuit)

IEC 61000-4-6 10Vr.m.s, Criteria A

CS (With AMFW72-13NZ)

IEC 61000-4-6 10Vr.m.s, Criteria A

Voltage dip (Without external circuit)

NA

Voltage dip (With AMFW72-13NZ)

NA

 

AMFW110-0.9NZ

Model

AM50QB-NZ 110Vin

AM75QB-NZ 110Vin

AM100QB-NZ 110Vin

EMI (Without external circuit)

NA

NA

EN55032, Class A

EMI (With AMFW110-0.9NZ)

EN55032, Class B

ESD (Without external circuit)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

ESD (With AMFW110-0.9NZ)

IEC 61000-4-2 Contact ±6KV / Air ±8KV, Criteria B

RS (Without external circuit)

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

IEC61000-4-3 10V/m,  Criteria A

RS (With AMFW110-0.9NZ)

IEC 61000-4-3 10V/m, Criteria A

EFT (Without external circuit)

NA

NA

NA

EFT (With AMFW110-0.9NZ)

IEC 61000-4-4 ±2KV,Criteria B

Surge (Without external circuit)

NA

NA

NA

Surge (With AMFW110-0.9NZ)

IEC 61000-4-5 ±2KV /±4KV, Criteria B EN50155 ±1.8KV, Criteria B

CS (Without external circuit)

IEC 61000-4-6 10Vr.m.s, Criteria A

IEC 61000-4-6 10Vr.m.s, Criteria A

IEC 61000-4-6 10Vr.m.s, Criteria A

CS (With AMFW110-0.9NZ)

IEC 61000-4-6 10Vr.m.s, Criteria A

Voltage dip (Without external circuit)

NA

NA

NA

Voltage dip (With AMFW110-0.9NZ)

EN50155 100%-0%,10msCriteria A


 

 

 

Notes: Information furnished is believed to be accurate and reliable. However, Aimtec assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Aimtec. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. Aimtec Products are not authorized for use as critical components in life support devices or systems without express written approval of Aimtec.                                                     © 2020 Aimtec. – All Rights Reserved