Line Impedance Stabilization Networks (LISN) are specialized low pass filter networks used to measure common mode conducted emissions from power lines. Fischer Custom Communications, Inc. has developed over 20 different Line Impedance Stabilization Networks to meet compliance testing requirements and custom customer needs. FCC LISN's are available for pre-compliance and compliance testing in accord with CISPR, VDE, IEC, DO-160 and Mil-Std. 461/462 Rev D.

Fischer Custom Communications, Inc. develops and manufactures Line Impedance Stabilization Networks or Artificial Mains Networks covering the frequency range from 6 kHz to 1,000 MHz.
The LISN must maintain a characteristic impedance to the EUT and isolate the EUT from unwanted RF signals on both the DC and AC power source while allowing the necessary voltage and current to be delivered to the EUT. The LISN provides a 50W output impedance for measurement of RF emissions produced by the EUT. A typical test configuration is shown.
Transfer impedance, voltage rating, current rating, number of power conductors and connector types are the key parameters in the selection of an LISN.
The impedance versus frequency of an LISN must match the requirements of the test specification being applied to the EUT. Most LISN attributes are defined in CISPR 16-1. The most widely used LISN's present a 50W impedance to the EUT. The 50W impedance was selected because theoretical and empirical data have shown that the power circuitry statistically looks like a 50W impedance to standard electronic equipment and RF test equipment is typically designed for 50W input. The bandwidth is typically determined by the operating frequency of the potential victims of the EUT's conducted emissions. The majority of conducted emission measurements are carried out form 150 kHz to 30 MHz. This insures that electronic equipment do not interfere with VLF, HF radio communication systems as well as other electronic devices operating at this frequency.
A prime example of this type of LISN is the 50?50 µH configuration defined in CISPR 16-1. The schematic and the transfer impedance for this LISN are shown below. The CISPR 16-1 limit lines are shown in bold.
The model FCC-LISN-50-25-2 is produced in accord with the required schematic of CISPR 16-1 and meets the frequency requirements. The impedance versus frequency curve of this LISN is superimposed on the impedance curve of for the 50W50W µH configuration. The 50W50W µH configuration is often used for Mil Std conducted emission testing from 10 kHz to 10 MHz. For specific details refer to Mil Std 461/462 D.

In addition to this LISN there are 50W versions used to test both to lower and higher frequencies. VDE 0876 and CISPR 16-1 can require conducted emission measurements on electronic devices from 9 kHz to 30 MHz. In order to extend the frequency to 9 kHz a 250 µH inductor and additional resistor and capacitance networks are added to the 50W50W µH configuration. CISPR 16-1 defines this LISN as 50W50W µH + 5 W. This type of LISN is often used when testing equipment with switch mode power supplies.

In contrast the aerospace, automotive and aircraft industries require conducted emission testing to frequencies higher than 30 MHz. To achieve the higher bandwidth a 5 µH inductor is used.

Voltage and current rating of the LISN are the second characteristic. It is important so select LISN's with ratings that allow the EUT to operate as intended. Fischer Custom Communications, Inc. offers LISN's with voltage rating from 240 to 500 volts RMS line to line and current ratings from 16 A to 200 A..

The third parameter is the number of power conductors or lines. EMI specifications require all EUT power leads except ground leads to be tested for conducted emissions. Any neutral or ground wires not connected to the chassis inside the EUT must be tested. DC and AC single phase power circuits must be tested using LISN modules containing two lines. A delta, three phase power network requires tests to be conducted with a LISN's containing three power conductors, and a Y or star, three phase system must be tested with LISN modules having four lines. To maximize flexibility Fischer Custom Communications, Inc. offers LISN modules containing one, two and four power conductors.

Fischer Custom Communications Inc. offers over twenty connectors. The key characteristics are electrical and mechanical safety in compliance with IEC 1010, not cause the impedance of the LISN to vary and match the EUT power mains requirement. All Fischer Custom Communications Inc. LISN's come with transfer impedance curves demonstrating compliance with specifications. We strongly recommend that IEC 320 or NEMA connectors be used to eliminate power cords.
All of Fischer Custom Communications, Inc. LISN's are easily mounted to the ground plane using our standard baseplate. Additional grounding is available.
LISN Selection Guide Codes
Connector Code
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19

Multi-Contact Satety Socket
Superior Plug and Jack Safety Socket
IEC 320, 10 A / 16A Power
IEC 320, 10 A / 16A Power
French /Belgium 16 A Power
BS 1363 13 A British Power
CEE 7/7 16A Schuko Berman Power
Nema 5-15, 15 A US Power
Nema 5-15, 15 A US Power
IEC 309, 16 A 3-Wire Power
IEC 309, 16 A 3-Wire Power
Hubbel 330P6W, 30 A 3-Wire US Power
Hubbel 330P6W, 30 A 3-Wire US Power
Hubbel 330P6W, 30 A 3-Wire US Power
Hubbel 330P6W, 30 A 3-Wire US Power
IEC 309, 32 A 5-Wire Power
IEC 309, 32 A 5-Wire Power
IEC 309, 32 A 5-Wire Power
LC Coaxial for Tempest

Chassis Dimensions
#1
#2
#3
#4
#5
#6
#7

Length X Width X Height 
23 cm X 15 cm X 13 cm
31 cm X 18 cm X 16 cm
38 cm X 23 cm X 18 cm
38 cm X 31 cm X 31 cm
61 cm X 36 cm X 36 cm
76 cm X 46 cm X 46 cm
76 cm X 61 cm X 51 cm

Test Type Code
01
02
03
04
05
06
07
08
09

CISPR / EN
FCC Part 15 / ANSI 63.4
FCC Part 18
Mil Std 461/462 Rev C
Mil Std 461/462 Rev D
D0 - 160 Faa
SAE J1113
TEMPEST
VCE 0876, Part 1

Filtered LISN's remotely switched LISN's and low profile LISN's for under turn table mounting and special versions operating to 1 GHz are now available.

Remotely switched LISN's may be controlled by the remote control or via a personal computer (PC) with a digital I/O card that can output 0-5 volt DC logic levels. The remote control and 50 foot cable are supplied with matching 9-pin D-type connectors. The remote connector is filtered to prevent external noise from entering the LISN enclosure.
LISN Selection Guide
Model Maximum
Frequency		 Network
Inductance		 Maximum
Current		 *Standard
Maximum Voltage		 Standard Power
Source Frequency		 # of Power
Conductors		 Chassis
Type		 Power Connector
Options		 Test Type
FCC-LISN-5-50-1 0.1-100 MHz 50W/5µH 50 A 240 DC - 60Hz 1 #1 2

01, 02 & 04

FCC-LISN-5-50-1-DO-160 0.1-400 MHz 50W/5µH 50 A 240 DC - 60Hz 1 #1 2

06 & 07

FCC-LISN-5-50-1-T 0.1-1,000 MHz 50W/5µH 50 A 240 DC - 60Hz 1 #1 19

8

FCC-LISN-5-100-1 0.1-65 MHz 50W/5µH 100 A 240 DC - 60Hz 1 #2 2

01, 02, 04, 07

FCC-LISN-50-50-1 0.15-100MHz 50W/50µH 50 A 240 DC - 60Hz 1 #2 2

01, 02, 05

FCC-LISN-50-100-1 0.15-30 MHz 50W/50µH 100 A 240 DC - 60Hz 1 #4 2

01, 02, 05

FCC-LISN-50-200-1 0.15-30 MHz 50W/50µH 200 A 240 DC - 60HZ 1 #5 2

01, 02, 05

FCC-LISN-57-50-1 0.01-10MHz 50W/57µH 50 A 240 DC - 60HZ 1 #2 2

4

FCC-LISN-50-25-2 0.15-100MHz 50W/50µH 25 A 240 DC - 60HZ 2 #3 01-10

01,02 & 05

FCC-LISN-50-32-2 0.15-100MHz 50W/50µH 32 A 240 DC - 60HZ 2 #3

01 - 10, 12

01,02 & 05

FCC-LISN-50-50-2 0.15-100MHz 50W/50µH 50 A 240 DC - 60HZ 2 #4

2

01 & 02

FCC-LISN-50-32-4 0.15-100MHz 50W/50µH 32 A 240 DC - 60HZ 4 #4

01,13,15,16

01, 02 & 05

FCC-LISN-50-50-4 0.15-100MHz 50W/50µH 50 A 240 DC - 60HZ 4 #4

02, 17

01, 02 & 05

FCC-LISN-50-100-4 0.15-30MHz 50W/50µH 100 A 240 DC - 60HZ 4 #6

02, 18

01, 02 & 05

FCC-LISN-50/250-25-2 0.009-100MHz 50W/50µH + 5W
50/250 µH		 25 A 240 DC - 60HZ 2 #4

01 - 10

01 & 09

FCC-LISN-50/250-32-2 0.009-100MHz 50W/50µH + 5W
50/250 µH

32 A

240 DC - 60HZ 2

#4

01, 10, 12

01 & 09

FCC-LISN-50/250-32-4 0.009-100MHz 50W/50µH + 5W
50/250 µH

32 A

240 DC - 60HZ 4

#5

01, 13,15, 16

01 & 09

FCC-LISN-50/250-50-2 0.009-100MHz 50W/50µH + 5W
50/250 µH

50 A

240 DC - 60HZ 2

#4

2

01 & 09

FCC-LISN-50/250-50-4 0.009-100MHz 50W/50µH + 5W
50/250 µH

50 A

240 DC - 60HZ 4

#5

02, 17

01 & 09

FCC-LISN-50/250-100-2 0.009-30MHz 50W/50µH + 5W
50/250 µH

100 A

240 DC - 60HZ 2

#7

2

01 & 09

Line Impedance Stabilization Network for ISO 7637-1 and SO 7637-2
FCC-LISN-5-( )-1-01-CISPR25 Impedance Stabilization Network
FCC-LISN-5-10-1-DEF-STAN-59-41
FCC-LISN-50/250-16-2-07 Line Impedance Stabilization Network
© 2004 Copyright FISCHER CUSTOM COMMUNICATIONS, INC. All rights reserved
20603 Earl Street • Torrance, CA 90503 • Tel: (310) 303-3300 • Fax: (310) 371-6268
E-mail: sales@fischercc.com