High Voltage

Planar Resistors

4500 Series

High Voltage

Planar Resistors

4500 Series

Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com

Issue B · 03.02

Welwyn Components

206

Application Notes

The terminations should not be bent closer than 1.5mm from

the body, and the recommended minimum bend radius is 1mm.

Due to the high voltage which can appear between the resistor

body and any adjacent metal part, resistors should be mounted

at an adequate distance from other conducting parts.

Due to the possibility of surface condensation it is

recommended that high voltages are not applied to resistors

in conditions of high humidity.

Design Flexibility

The experience of Welwyn engineers has been used to design

this generation of high voltage planar resistors to be suitable

for a majority of applications. However, should an application

require particular consideration, Welwyn designers are

available to provide advice and where applicable, to

recommend a non-standard product. Special sizes, designs

etc, can be prototyped at short notice.

Non Standard Optional Features

The options listed below are some of the special features

which may be provided, subject to agreement.

Special substrate size.

Leadless version with palladium silver solder pads.

Special termination length, diameter and pitch.

Special designs for pulse applications.

Resistance value outside stated range.

Tolerance better than ± 1%

Temperature coefficient of ± 50ppm/°C.

Enquiries Welcomed

Packaging

Packed in foam within a box.

Construction

A high quality alumina substrate is printed with a specially

selected high voltage thick film resistor ink based on a

ruthenium oxide/glass system. A choice of protective systems

is available.

Choice of Protection

As standard components are supplied conformally coated

with an epoxy resin. By special request components can be

supplied unprotected or with a screen printed epoxy

‘handling’ protection.

Terminations

Material

Solder coated phosphor bronze leadframe.

Resistors can be supplied without leads, in

which case palladium silver pads enable

electrical connection to be made.

Strength

The terminations meet the requirements of

IEC 68.2.21.

Solderability The terminations meet the requirements of

IEC 115-1, Clause 4.17.3.2

Marking

Type and protection system references, resistance value

tolerance and manufacturing date code are legend marked.

The resistance value conforms to IEC 62.

Solvent Resistance

The body protection and marking are resistant to all normal

industrial cleaning solvents suitable for printed circuits.

Actual

Maximum

Typical

Load at rated power: 1000 hours at 70°C

∆R%

0.3

0.02

0.02

5

0.3

Shelf life: 12 months at room temperature

∆R%

<0.1

Derating

Zero at 125°C

Temperature rapid change

∆R%

0.1

Resistance to solder heat

∆R%

0.05

Voltage coefficient of

4501 and 4502

5

<3

Resistance ppm/volt

4503 and 4504

3

<2

4505, 4506 and 4507

1.5

<1

Performance Data

4500 series new 2/6/03 4:01 pm Page 2

High Voltage

Planar Resistors

4500 Series

Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com

Issue B · 03.02

Welwyn Components

206

Application Notes

The terminations should not be bent closer than 1.5mm from

the body, and the recommended minimum bend radius is 1mm.

Due to the high voltage which can appear between the resistor

body and any adjacent metal part, resistors should be mounted

at an adequate distance from other conducting parts.

Due to the possibility of surface condensation it is

recommended that high voltages are not applied to resistors

in conditions of high humidity.

Design Flexibility

The experience of Welwyn engineers has been used to design

this generation of high voltage planar resistors to be suitable

for a majority of applications. However, should an application

require particular consideration, Welwyn designers are

available to provide advice and where applicable, to

recommend a non-standard product. Special sizes, designs

etc, can be prototyped at short notice.

Non Standard Optional Features

The options listed below are some of the special features

which may be provided, subject to agreement.

Special substrate size.

Leadless version with palladium silver solder pads.

Special termination length, diameter and pitch.

Special designs for pulse applications.

Resistance value outside stated range.

Tolerance better than ± 1%

Temperature coefficient of ± 50ppm/°C.

Enquiries Welcomed

Packaging

Packed in foam within a box.

Construction

A high quality alumina substrate is printed with a specially

selected high voltage thick film resistor ink based on a

ruthenium oxide/glass system. A choice of protective systems

is available.

Choice of Protection

As standard components are supplied conformally coated

with an epoxy resin. By special request components can be

supplied unprotected or with a screen printed epoxy

‘handling’ protection.

Terminations

Material

Solder coated phosphor bronze leadframe.

Resistors can be supplied without leads, in

which case palladium silver pads enable

electrical connection to be made.

Strength

The terminations meet the requirements of

IEC 68.2.21.

Solderability The terminations meet the requirements of

IEC 115-1, Clause 4.17.3.2

Marking

Type and protection system references, resistance value

tolerance and manufacturing date code are legend marked.

The resistance value conforms to IEC 62.

Solvent Resistance

The body protection and marking are resistant to all normal

industrial cleaning solvents suitable for printed circuits.

Actual

Maximum

Typical

Load at rated power: 1000 hours at 70°C

∆R%

0.3

0.02

0.02

5

0.3

Shelf life: 12 months at room temperature

∆R%

<0.1

Derating

Zero at 125°C

Temperature rapid change

∆R%

0.1

Resistance to solder heat

∆R%

0.05

Voltage coefficient of

4501 and 4502

5

<3

Resistance ppm/volt

4503 and 4504

3

<2

4505, 4506 and 4507

1.5

<1

Performance Data

4500 series new 2/6/03 4:01 pm Page 2

11.17

General Note

TT Electronics reserves the right to make changes in product specification without notice or liability.

All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.

© TT Electronics plc

www.ttelectronics.com/resistors

BI Technologies IRC Welwyn