Tekbox TBOH01 User guide

V1.7

TBOH01

TBOH01 5µH LISN MANUAL

The TBOH01 5µH LISN is a device required to setup conducted noise mesurements of DC-powered
devices. It is designed to be used for EMC pre-testing in the frequency range of 150kHz to 110 MHz
according to the CISPR-25 standard, ISO 7637-2, ISO11452-2/4/5 and with limitations DO-160/ED-14G.
The LISN is inserted into the supply line of the DUT (Device Under Test). Conducted noise which is
present at the supply terminals of the DUT can be measured at the BNC connector using a spectrum
analyzer or a measurement receiver. The source (supply) terminal and the DUT terminal are decoupled
by a 5µH inductor.

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V1.7

TBOH01

CONTENTS

TBOH01 5 µ H LISN MANUAL

1 INTRODUCTION 2

1.1 PARAMETERS 2

1.2 SCHEMATIC 2

1.3 IMPEDANCE 3

1.4 FREQUENCY RESPONSE 4

1.5 CALIBRATION DATA ACCORDING
TO CISPR 16 -1-2 ANNEX A8 7

2 APPLICATION 9

2.1 STANDARD SETUP 9

2.2 SETUP FOR MEASURING POWER SUPPLY NOISE
SPECTRUM OF POWER SUPPLIES 10

2.3 SETUP FOR RF IMMUNITY TESTING 10

3 CISPR 25 LIMITS FOR BROADBAND CONDUCTED
EMISSIONS ON POWER INPUT TERMINALS 11

4 MEASUREMENT EXAMPLES 11

5 HISTORY 12

TABLES

Table 1 – Insertion loss measured between DUT and BNC terminal; Source terminals open/shorted 6

Table 2 - TBOH01 LISN calibration data 8

Tables 3,4 – Tables 2,3 are just a simplified excerpt. Refer to the standard for further details 11

Table 5 – History 12

PICTURES

Picture 1 – 300kHz…100MHz, measured impedance of the 5µH LISN 3

Picture 2 – 0,3…3MHz, insertion loss measured between DUT terminals and BNC connector; source terminals shorted 4

Picture 3 – 0,3…100MHz, insertion loss measured between DUT terminals and BNC connector; source terminals shorted 4

Picture 4 – 0 ,3…1GHz, insertion loss measured between DUT terminals and BNC connector; source terminals shorted 5

Picture 5 – 0,3…100MHz, isolation measured between DUT and source terminals; BNC connector terminated with 50Ω 5

Picture 6 – Calibration set up according to CISPR 16-1-2 Annex A.8 7

Picture 7 – Basic functionality of a LISN 9

Picture 8 – Example setup for a conducted noise measurement of a DC powered device 9

Picture 9 – Setup for measuring power supply noise spectrum 10

Picture 10 – Setup for RF injection 10

Picture 11 – Simple laboratory set up 11

Picture 12 – conducted emissions, frequency range 150kHz to 108MHz 12

Picture 13 – Example: conducted emissions, pre-compliance measurement of an automotive LED driver using two LISNs 12

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1. INTRODUCTION

The TBOH01 5µH LISN is a device required to setup conducted noise
measurements of DC-powered devices. It is designed to be used
for EMC pre-testing in the frequency range of 150kHz to 110 MHz
according to the CISPR-25 standard, ISO 7637-2, ISO11452-2/4/5
and with limitations DO-160/ED-14G.
The LISN is inserted into the supply line of the DUT (Device Under
Test). Conducted noise which is present at the supply terminals of
the DUT can be measured at the BNC connector using a spectrum
analyzer or a measurement receiver. The source (supply) terminal
and the DUT terminal are decoupled by a 5µH inductor.

1.1. PARAMETERS

Frequency range: 100kHz – 110MHz (1GHz,
see figure 4)

DC Resistance: 40 mΩ

Maximum current: 10A
Nominal operating voltage range: 0 – 75V DC;

Absolute maximum rating: 200V

Built in surge protection

Terminals suitable to clamp external source
capacitors

TBOH01 5 µ H LISN MANUAL

1.2 SCHEMATIC

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2

0

15

30

45

60

0110

100

TBOH01 5 µ H LISN MANUAL

P1: DUT+; P3: SOURCE+; CON1: SPECTRUM ANALYZER / MEASUREMENT RECEIVER

BOM:

C1 C3216X7R2E104K 100nF 250V X7R 1206 TDK Corporation Digikey

C2 1206PC102KAT1A 1nF 250V X7R 1206 AVX Digikey

C3, C4 501R18N330JV4E 33pF 500V NP0 1206 Johanson Digikey

C5 C3225X7R2E224M 220nF 250V X7R 1210 TDK Corporation Digikey

CON1 DOSIN-801-0034 BNC 50Ω 180° PCB mount Dosin Dosin

GDT1 2031-15T-SM-RPLF GAS TUBE 60V 1KA Bourns Inc. Digikey

HOUSING 1550DBK or 1550D BOX ALUM 4.51X2.52X2.17” Hammond Digikey

L1, L2, L3, L4 1.25µH; 8 turns, ∅17mm ∅1,4mm enamelled copper wire

MOV1 MOV-20D271K VARISTOR 270V 20MM Bourns Inc. Digikey

P1, P2, P3, P4 Banana Jacks

PCB 5µH LISN V1.0 double sided, 95x58x1.6mm FZ-Electronics FZ

R1 RC1206FR-071KL RES 1K OHM 1/4W 1% 1206 Yageo Digikey

R2 RC1206FR-07470RL RES 470 OHM 1/4W 1% 1206 Yageo Digikey

R3, R4 4-1622820-8 RES 470 OHM 1W 5% 2512 TE Connectivity Digikey

R5, R6 1622820-4 RES 10 OHM 1W 5% 2512 TE Connectivity Digikey

TVS1, TVS2 ESD9L5.0ST5G TVS ULT LOW CAP SOD-923 ON-Semiconductor Digikey

1.3. IMPEDANCE



Picture 1 – 300kHz…100MHz, measured impedance of the 5µH LISN

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5µH LISN Impedance
CISPR-25 Lower Limit
CISPR-25 Upper Limit

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1.4. FREQUENCY RESPONSE

TBOH01 5 µ H LISN MANUAL

Picture 2 – 0,3…3MHz, insertion loss measured between DUT terminals and BNC connector;
source terminals shorted

Picture 3 – 0,3…100MHz, insertion loss measured between DUT terminals and BNC
connector; source terminals shorted

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TBOH01 5 µ H LISN MANUAL

Picture 4 –0 ,3…1GHz, insertion loss measured between DUT terminals and BNC connector;
source terminals shorted

Picture 5 – 0,3…100MHz, isolation measured between DUT and source terminals; BNC

connector terminated with 50Ω

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TBOH01 5 µ H LISN MANUAL

Frequency

Max. insertion loss (DUT terminals to

BNC; source terminals open)

Max. insertion loss (DUT terminals to

BNC; source terminals shorted)

150 kHz -16.3 dB -12.7 dB

200 kHz -13.5 dB -10.3 dB

250 kHz -11.1 dB -8.5 dB

300 kHz -9 dB -7.2 dB

350 kHz -7.8 dB -6.1 dB

400 kHz -6.7 dB -5.3 dB

450 kHz -5.9 dB -4.7 dB

500 kHz -5.1 dB -3.9 dB

600 kHz -4.2 dB -3.4 dB

700 kHz -3.5 dB -3 dB

800 kHz -3 dB -2.5 dB

900 kHz -2.7 dB -2.3 dB

1 MHz -2.5 dB -2.1 dB

5 MHz -1.2 dB -1.2 dB

10 MHz -0.7 dB -0.7 dB

50 MHz -0.8 dB -0.8 dB

100 MHz -1 dB -1 dB

150 MHz -1.2 dB -1.2 dB

250 MHz -1.9 dB -1.9 dB

Table 1, insertion loss measured between DUT and BNC terminal; Source terminals open/shorted

SOURCE CAPACITORS:

CISPR 25 and ISO 11452-2/4/5 specify a 1µF capacitor to be connected in parallel to the source terminals. The TBOH01 terminals have perpendicular

holes to easily insert and clamp the pins of the external capacitor. DO-160 specifies a 10µF capacitor in parallel to the source terminals. However,

consider that the TBOH01 is not specified for the full DO-160 frequency range. Use the correction table column “source terminals shorted” for these

applications. ISO7637-2 does not specify an external capacitor. Use the correction table column “source terminal open” then.

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1.5. CALIBRATION DATA ACCORDING TO CISPR 16 -1-2 ANNEX A8

Calibration set up according to CISPR 16-1-2 Annex A.8.

TBOH01 5 µ H LISN MANUAL

Picture 6 – Calibration set up according to CISPR 16-1-2 Annex A.8.

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TBOH01 5 µ H LISN MANUAL

Frequency

[MHz]

Insertion loss CISPR-25 and

ISO1145-2/4/5

(1µF across source terminals) [dB]

Insertion loss DO-160

(10µF across source terminals) [dB]

Insertion loss ISO7637-2

(no capacitor across source

terminals] [dB]

0.03 -3.9 -3.6 -3.53

0.05 -1.8 -1.77 -1.7

0.1 -0.6 -0.53 -0.56

0.5 -0.1 -0.09 -0.08

1 -0.1 -0.19 -0.17

10 -0.15 -0.16 -0.13

20 -0.25 -0.26 -0.25

30 -0.42 -0.44 -0.43

40 -0.61 -0.63 -0.62

50 -0.84 -0.85 -0.85

60 -1.07 -1.09 -1.07

70 -1.3 -1.33 -1.3

80 -1.56 -1.58 -1.57

90 -1.86 -1.88 -1.86

100 -2.15 -2.2 -2.19

110 -2.33 -2.37 -2.35

120 -2.55 -2.6 -2.57

130 -2.73 -2.79 -2.74

140 -2.91 -3.05 -3

150 -3.1 -3.17 -3.12

160 -3.3 -3.37 -3.34

170 -3.5 -3.59 -3.55

180 -3.71 -3.79 -3.77

190 -3.9 -3.95 -3.92

200 -4.05 -4.13 -4.07

Table 2, TBOH01 LISN calibration data

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2. APPLICATION

A Line Impedance Stabilisation Network basically is a coupling device to
measure conducted noise present on supply lines with a measurement
receiver or spectrum analyzer. It establishes a defined impedance
setup for the measurement, independent of the impedance of the power
source. Hence the name Line Impedance Stabilisation Network.
A LISN has three terminals – both ends of a feedthrough path for DC

and a 50 Ω coaxial terminal to connect a measurement receiver or

spectrum analyzer.

Conducted noise from the Device Under Test (DUT) is coupled from the

supply line to a 50 Ω BNC terminal.

Coupling loss from the DUT connector to the BNC connector is less than
1 dB from 3 MHz to 100 MHz. On the other hand, the LISN isolates the
DUT and BNC terminals from conducted noise coming from the source
side (Figure 5).

TBOH01 5 µ H LISN MANUAL

The DUT can be any DC powered electronic device. The Source can be
any DC power supply up to 200V max.

Though the LISN is normally used to measure conducted noise from a
DC powered device, it ccould also be used to inject RF to the supply

lines of the DUT. This setup requires an additional 50 Ω feedthrough

terminal at the BNC connector. Furthermore the LISN could be used
to measure the noise of a source, for example a switched mode power
supply or a DC/DC converter output. In this case, the power supply has
to be connected to the DUT terminals and a load has to be connected
to the Source terminals.

The test configurations shown in the following chapters are just
examples and not strictly according to standards. They should rather
serve as an easy means to carry out EMC pre-testing in the lab, before
going to a certified test house.
Setup dimensions, Limits for spurious levels, bandwidth and detector
settings for the measurement receiver or spectrum analyzer have to be
derived from the applied standards.

2.1. STANDARD SETUP

Conducted noise measurements are typically conducted using a sheet
metal as ground plane. The GND terminals of all involved devices are
connected to the metal shield using short cables.

As the measurement will be conducted in lab, rather than in a shielded
chamber, a background noise measurement should be carried out with
the DUT switched off or disconnected in order to be able to differentiate
between conducted noise spectrum and background electric smog.

Picture 7 – basic functionality of a LISN

Standard conformant measurements would make use of two LISNs, if
the vehicle power return line of the DUT is longer than 200 mm. One
in the positive and another one in the negative supply line and then
alternatively measure the noise. For a precompliance measurement,
measuring the positive supply line gives a good indication on the
performance of the device. The measurement can then be repeated
with the LISN inserted into the negative supply line to check if the noise
levels are any different.

Professional conducted noise measurements are done in shielded
chambers, as any RF smog picked up by the wires from LISN to DUT or
by the DUT itself, will be present at the BNC terminal. Consequently, a
measurement with the DUT powered off should be done upfront in order
to distinguish between real conducted noise generated by the DUT and
RF smog from other sources (background noise).

The picture below shows a typical conducted emissions measurement
setup, such as specified in CISPR-25 standard. Setup details will differ
depending on the type of DUT and applicable standards. For example,
if the DUT has a vehicle power return line shorter than 200 mm, one
LISN is inserted into the positive supply line. If the vehicle return line
of the DUT is longer than 200 mm, two LISNs are required. One for the
positive supply line and one for the power return line.

Picture 8 – example setup for a conducted noise measurement of a DC powered device

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TBOH01 5 µ H LISN MANUAL

2.2. SETUP FOR MEASURING POWER SUPPLY NOISE SPECTRUM OF POWER SUPPLIES

The LISN can also be used to measure noise spectrum at the output terminals of a power supply or switched mode regulator.

Picture 9 – setup for measuring power supply noise spectrum

Kindly notice again, that for exact set ups, you need to check the standards applicable to your DUT, especially CISPR 25, chapter 6.1.2 which defines
if one or two LISNs have to be used for the setup.

2.3. SETUP FOR RF IMMUNITY TESTING

By adding a 50 Ohm feed through termination, the LISN can also be utilized to inject RF into the supply line of the DUT. The power rating of the
feedthrough termination has to match the injected RF power level.

Picture 10 – setup for RF injection

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TBOH01 5 µ H LISN MANUAL

3. CISPR 25 LIMITS FOR BROADBAND CONDUCTED EMISSIONS ON
POWER INPUT TERMINALS

Levels in dBµV

CLASS

0,15 – 0,3 MHz 0,53 – 1,8 MHz 5,9 – 6,2 MHz 30 – 54 MHz 76 – 108 MHz

Peak

Quasi

Peak

Peak

Quasi

Peak

Peak

Quasi

Peak

Peak

Quasi

Peak

Peak

1 110 97 86 73 77 64 68 55 62 49

2 100 87 78 65 71 58 62 49 56 43

3 90 77 70 57 65 52 56 43 50 37

4 80 67 62 49 59 46 50 37 44 31

5 70 57 54 41 53 40 44 31 38 25

For short duration disturbances, add 6 dB to the level shown in the table

Measuring instrument bandwidth (6 dB)

Frequency band [MHz] Broadband peak or quasi-peak Narrowband peak or average

0,15 - 30 9 kHz 9 kHz

30 – 1000 FM Broadcast

Mobile Service

120 kHz
120 kHz

120 kHz

9 kHz

Quasi

Peak

The tables 3,4 above are just a simplified excerpt. Refer to the standard for further details

4. MEASUREMENT EXAMPLES

The picture to the right shows a simple set up to do a quick test
of a 9V to 24V USB car charger adapter. The charger adapter
gets supplied with 12 V at the DUT terminals of the LISN.
The power supply is connected to the Source terminals of the
LISN. A spectrum analyzer is connected to the BNC connector
of the LISN.

SPECTRUM ANALYZER SETTINGS:

Frequency: 150kHz - 3MHz
Detector Type: Positive Peak (use Max. Hold or Quasi Peak,
if available)

Filter Type: EMI

BW: 9kHz

Internal Attenuator: OFF

Units: dBµV

The setup is not CISPR25 conformant – no metal ground plane is involved. Nevertheless, the measurement permits a judgement of the conducted emission

performance of the DUT and will be very useful to determine, if modications of the circuit result in improved suppression of conducted emissions.

Picture 11 – simple laboratory set up

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TBOH01 5 µ H LISN MANUAL

The screenshot below shows the result of a CISPR 25 conducted noise measurement of a DC/DC converter carried out with two TBOH01, a Rigol
DSA815 and the Tekbox PC SW EMCview. With reference to the CISPR 25 limits, the measurement result shows compliance with Class 5 limits.

Picture 12 – conducted emissions, frequency range 150kHz to 108MHz

Picture 13 – Example: conducted emissions, pre-compliance measurement
of an automotive LED driver using two LISNs

5. HISTORY

Version Date Author Changes

V1.0 14.09.2010 L.D.HIEU Creation of the document

V1.1 18.11.2013 L.D.HIEU Chapter 2 updated

V1.2 17.03.2014 L.D.HIEU Part number of R2 corrected

V1.3 25.11.2014 MAYERHOFERs Chapter 1.1 updated

V1.4 17.01.2016 MAYERHOFER Insertion loss table added

V1.5 8.8.2016 MAYERHOFER Picture 12 added

V1.6 24.4.2017 MAYERHOFER Updated chapters 1, 1.4, 3, 4

V1.7 13.12.2017 MAYERHOFER Chapters 1.5 added

Table 5 – History

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