WO2003019581A1 - Ptc resistor in smd form - Google Patents

Ptc resistor in smd form Download PDF

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Publication number
WO2003019581A1
WO2003019581A1 PCT/NL2002/000560 NL0200560W WO03019581A1 WO 2003019581 A1 WO2003019581 A1 WO 2003019581A1 NL 0200560 W NL0200560 W NL 0200560W WO 03019581 A1 WO03019581 A1 WO 03019581A1
Authority
WO
WIPO (PCT)
Prior art keywords
ptc resistor
ceramic section
terminal
resistor according
ceramic
Prior art date
Application number
PCT/NL2002/000560
Other languages
French (fr)
Inventor
André Lannoo
Bruno Van Beneden
Erik Mattens
Jos De Witte
Original Assignee
Bc Components Holdings B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bc Components Holdings B.V. filed Critical Bc Components Holdings B.V.
Publication of WO2003019581A1 publication Critical patent/WO2003019581A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C1/00—Details
    • H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
    • H01C1/1406—Terminals or electrodes formed on resistive elements having positive temperature coefficient

Definitions

  • the present invention relates to a PTC resistor, i.e. an electrical element whose resistance increases as the temperature rises. More particularly, the present invention relates to a PTC resistor, comprising a ceramic section and two terminal connections.
  • PTC resistors which comprise a ceramic element are known in the prior art, but in particular in standard designs with connection wires.
  • the present invention seeks to provide a PTC resistor which is suitable in particular for use in surface mounting (surface mount device, SMD).
  • the present invention provides a PTC resistor of the type defined in the preamble in which the ceramic section is a beam-like ceramic section and in which the two terminal connections make electrical contact with two opposite sides of the beam-like ceramic section.
  • a PTC resistor according to the present invention has the advantage that the upper side forms a planar pick-up section, so that surface mounting on a substrate or printed circuit board (PCB) can easily be carried out automatically.
  • PCB printed circuit board
  • Different operating ranges with regard to resistance and operating temperatures are possible with only a small footprint (surface-area coverage).
  • one side of the PTC resistor is of substantially planar design, so that the PTC resistor is easy to pick up during the mounting of printed circuit boards.
  • This side is preferably the side which, after mounting of a printed circuit board, lies parallel to the printed circuit board and forms the top side of the PTC resistor.
  • the two opposite sides of the beam-like ceramic section are metalized. This simplifies the fabrication process of the PTC resistor, since the terminal connections are easy to secure, for example by soldering.
  • the beam-like ceramic section is made, for example, from a modified ferroelectric material. An appropriate selection of the properties of the ceramic material allows the PTC resistor to have various specifications.
  • each of the two terminal connections comprises at least one terminal lug which projects beyond the edge of the beam-like ceramic section, for example by substantially 0.2 mm.
  • This measure allows simple SMD mounting with an improved mechanical stability during the operating process.
  • forming a hollow or notch in the terminal connection towards the printed circuit board allows the heat flux from the PTC resistor to the substrate to be reduced, which improves the reliability of the circuit in which the PTC resistor is used.
  • the dimensions of the beam-like ceramic section can be selected as desired, but in certain embodiments this section has a length of between substantially 5 and 8 mm, a thickness of between substantially 2 and 3 mm and a height of between substantially 3 and 5 mm.
  • the at least one terminal lug has a width of substantially 5 mm.
  • these lugs have a width of substantially 1.5 mm, with if appropriate a space between them of substantially 2 mm (total width of terminal lugs and intervening space is substantially 5 mm).
  • Fig. 1 shows a side view of PTC resistor according to one embodiment of the present invention
  • Fig. 2 shows a cross-sectional view through a PTC resistor from Fig. 1 on line 11-13.
  • Fig. 1 shows a PTC resistor 10 according to one embodiment of the present invention.
  • PTC stands for Positive Temperature Coefficient, which means that the resistance of this electrical element increases as the temperature rises.
  • Fig. 2 shows a cross-sectional view through the PTC resistor 10 from Fig. 1 on line II-IL
  • the PTC resistor 10 according to the present invention is suitable in particular for surface mounting (Surface Mount Device, SMD) on a substrate or printed circuit board (PCB, not shown).
  • SMD Surface Mount Device
  • PCB printed circuit board
  • the PTC resistor 10 can be used for overvoltage, overcurrent and/or excess temperature protection in electronic circuits, such as telecommunications line cards, set-top boxes, base stations, SMPS power supplies, etc.
  • Using the present PTC resistor 10 in a SMD design makes it possible to replace complete hybrid protection circuits, currently stuck at right angles onto a PCB, by direct integration of the element 10 on the same PCB.
  • the PTC resistor 10 comprises a beam-like ceramic section 11 and two terminal connections 12 and is also known as a ceramic thermistor.
  • the beam-like ceramic section 11 can be sawn from a large block of ceramic material, such as modified ferroelectric materials.
  • L, height W and thickness T cf. Fig. 2
  • composition of the ceramic material it is possible to obtain a wide range of resistances and operating temperatures to protect against various levels of electric current, voltage or temperature. It is also possible to make PTC resistors 10 with varying properties while retaining standard dimensions of the footprint (length L and thickness T).
  • terminal connections 12 made from sheet material which make electrical contact with the beamlike ceramic section 11. This can be achieved, for example, by metalizing the opposite sides of the ceramic section and soldering the terminal connections 12 onto them.
  • the terminal connections 12 preferably have split terminal lugs 13, with a width b and an interspace p, so that the mechanical stability during processing is increased and the heat flux to the substrate is reduced.
  • the length L of the ceramic section may vary between 5 and 8 mm, and the width T may vary between 2 and 3 mm.
  • the height W can vary between 3 and 5 mm.
  • the thickness d of the sheet material of the terminal connections 12 is equal to 0.2 mm (+ or - 0.05 mm) and the terminal lugs 13 project 1 mm (+ or - 0.2 mm) below the ceramic section 11 (distance S in Fig. 1).
  • the width b of the terminal lugs 13 is equal to 1.5 mm (+ or - 0.2 mm), and the space p between two terminal lugs 13 of a terminal connection 12 is equal to 2 mm (+ or - 0.3 mm).
  • the compact design of the PTC resistor 10 results in a maximum height of 6 mm and a minimal footprint with respect to the substrate. This is made possible by the utilization of the opposite sides of the beam-like ceramic section 11 to secure the terminal connections 12.
  • the PTC resistor 10 according to the invention also offers a flat pick- up region on the top side of the PTC resistor 10, which simplifies processing by automatic component placing machines.
  • the design of the terminal connections 12 allows the use of reflow soldering techniques.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Details Of Resistors (AREA)
  • Thermistors And Varistors (AREA)

Abstract

PTC resistor (10), comprising a ceramic section (11) and two terminal connections (12). The ceramic section (11) is a beam-like ceramic section made, for example, from ferroelectric material. The two terminal connections (12) make electrical contact with two opposite sides of the beam-like ceramic section (11), it being possible for these sides to be metalized. One side of the PTC resistor (10) is of planar design.

Description

PTC resistor in SMD form
The present invention relates to a PTC resistor, i.e. an electrical element whose resistance increases as the temperature rises. More particularly, the present invention relates to a PTC resistor, comprising a ceramic section and two terminal connections.
PTC resistors which comprise a ceramic element are known in the prior art, but in particular in standard designs with connection wires.
The present invention seeks to provide a PTC resistor which is suitable in particular for use in surface mounting (surface mount device, SMD).
The present invention provides a PTC resistor of the type defined in the preamble in which the ceramic section is a beam-like ceramic section and in which the two terminal connections make electrical contact with two opposite sides of the beam-like ceramic section.
A PTC resistor according to the present invention has the advantage that the upper side forms a planar pick-up section, so that surface mounting on a substrate or printed circuit board (PCB) can easily be carried out automatically. Different operating ranges with regard to resistance and operating temperatures are possible with only a small footprint (surface-area coverage).
In one embodiment, one side of the PTC resistor is of substantially planar design, so that the PTC resistor is easy to pick up during the mounting of printed circuit boards. This side is preferably the side which, after mounting of a printed circuit board, lies parallel to the printed circuit board and forms the top side of the PTC resistor.
In one embodiment, the two opposite sides of the beam-like ceramic section are metalized. This simplifies the fabrication process of the PTC resistor, since the terminal connections are easy to secure, for example by soldering. The beam-like ceramic section is made, for example, from a modified ferroelectric material. An appropriate selection of the properties of the ceramic material allows the PTC resistor to have various specifications.
In a further embodiment, each of the two terminal connections comprises at least one terminal lug which projects beyond the edge of the beam-like ceramic section, for example by substantially 0.2 mm. This measure allows simple SMD mounting with an improved mechanical stability during the operating process. Furthermore, forming a hollow or notch in the terminal connection towards the printed circuit board allows the heat flux from the PTC resistor to the substrate to be reduced, which improves the reliability of the circuit in which the PTC resistor is used.
The dimensions of the beam-like ceramic section can be selected as desired, but in certain embodiments this section has a length of between substantially 5 and 8 mm, a thickness of between substantially 2 and 3 mm and a height of between substantially 3 and 5 mm.
In a further embodiment, the at least one terminal lug has a width of substantially 5 mm. In an embodiment with a plurality of terminal lugs per terminal connection, for example two, these lugs have a width of substantially 1.5 mm, with if appropriate a space between them of substantially 2 mm (total width of terminal lugs and intervening space is substantially 5 mm).
The present invention will now be explained in further detail on the basis of an exemplary embodiment and with reference to the appended drawing, in which:
Fig. 1 shows a side view of PTC resistor according to one embodiment of the present invention;
Fig. 2 shows a cross-sectional view through a PTC resistor from Fig. 1 on line 11-13.
Fig. 1 shows a PTC resistor 10 according to one embodiment of the present invention. PTC stands for Positive Temperature Coefficient, which means that the resistance of this electrical element increases as the temperature rises. Fig. 2 shows a cross-sectional view through the PTC resistor 10 from Fig. 1 on line II-IL The PTC resistor 10 according to the present invention is suitable in particular for surface mounting (Surface Mount Device, SMD) on a substrate or printed circuit board (PCB, not shown). The PTC resistor 10 can be used for overvoltage, overcurrent and/or excess temperature protection in electronic circuits, such as telecommunications line cards, set-top boxes, base stations, SMPS power supplies, etc. Using the present PTC resistor 10 in a SMD design makes it possible to replace complete hybrid protection circuits, currently stuck at right angles onto a PCB, by direct integration of the element 10 on the same PCB.
The PTC resistor 10 comprises a beam-like ceramic section 11 and two terminal connections 12 and is also known as a ceramic thermistor. The beam-like ceramic section 11 can be sawn from a large block of ceramic material, such as modified ferroelectric materials. By varying the three dimensions L, height W and thickness T (cf. Fig. 2), and by varying the composition of the ceramic material, it is possible to obtain a wide range of resistances and operating temperatures to protect against various levels of electric current, voltage or temperature. It is also possible to make PTC resistors 10 with varying properties while retaining standard dimensions of the footprint (length L and thickness T).
On two opposite sides of the beam-like ceramic section 11 there are two terminal connections 12 made from sheet material which make electrical contact with the beamlike ceramic section 11. This can be achieved, for example, by metalizing the opposite sides of the ceramic section and soldering the terminal connections 12 onto them. The terminal connections 12 preferably have split terminal lugs 13, with a width b and an interspace p, so that the mechanical stability during processing is increased and the heat flux to the substrate is reduced.
In an exemplary embodiment, the length L of the ceramic section may vary between 5 and 8 mm, and the width T may vary between 2 and 3 mm. The height W can vary between 3 and 5 mm. In an exemplary embodiment, the thickness d of the sheet material of the terminal connections 12 is equal to 0.2 mm (+ or - 0.05 mm) and the terminal lugs 13 project 1 mm (+ or - 0.2 mm) below the ceramic section 11 (distance S in Fig. 1). The width b of the terminal lugs 13 is equal to 1.5 mm (+ or - 0.2 mm), and the space p between two terminal lugs 13 of a terminal connection 12 is equal to 2 mm (+ or - 0.3 mm).
The compact design of the PTC resistor 10 results in a maximum height of 6 mm and a minimal footprint with respect to the substrate. This is made possible by the utilization of the opposite sides of the beam-like ceramic section 11 to secure the terminal connections 12. The PTC resistor 10 according to the invention also offers a flat pick- up region on the top side of the PTC resistor 10, which simplifies processing by automatic component placing machines. The design of the terminal connections 12 allows the use of reflow soldering techniques.

Claims

1. PTC resistor (10), comprising a ceramic section (11) and two terminal connections (12), characterized in that the ceramic section (11) is a beam-like ceramic section, the two terminal connections (12) making electrical contact with two opposite sides of the beam-like ceramic section (11).
2. PTC resistor according to Claim 1, in which one side of the PTC resistor (10) is of planar design.
3. PTC resistor according to Claim 1 or 2, in which the two opposite sides of the beam-like ceramic section (11) are metalized.
4. PTC resistor according to Claim 1, 2 or 3, in which the beam-like ceramic section (11) is made from a modified ferroelectric material.
5. PTC resistor according to one of the preceding claims, in which each of the two terminal connections (12) comprises at least one terminal lug (13) which projects beyond the edge of the beam-like ceramic section (11).
6. PTC resistor according to Claim 5, in which the terminal lugs (13) project substantially 0.2 mm beyond the edge of the beam-like ceramic section (11).
7. PTC resistor according to one of the preceding claims, in which the beam-like ceramic section (11) has a length (L) of between substantially 5 and 8 mm.
8. PTC resistor according to one of the preceding claims, in which the beam-like ceramic section (11) has a thickness (T) of between substantially 2 and 3 mm.
9. PTC resistor according to one of the preceding claims, in which the beam-like ceramic section (11) has a height (W) of between substantially 3 and 5 mm.
10. PTC resistor according to one of the preceding claims, in which each of the terminal connections (12) comprises at least one terminal lug (13) with a width (b) of substantially 5 mm.
11. PTC resistor according to one of the preceding claims, in which at least one of the terminal connections (12) comprises two terminal lugs (13) which are provided with an intervening space (P) of substantially 2 mm.
PCT/NL2002/000560 2001-08-23 2002-08-23 Ptc resistor in smd form WO2003019581A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1018807A NL1018807C2 (en) 2001-08-23 2001-08-23 PTC resistor in SMD version.
NL1018807 2001-08-23

Publications (1)

Publication Number Publication Date
WO2003019581A1 true WO2003019581A1 (en) 2003-03-06

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ID=19773907

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Application Number Title Priority Date Filing Date
PCT/NL2002/000560 WO2003019581A1 (en) 2001-08-23 2002-08-23 Ptc resistor in smd form

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WO (1) WO2003019581A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021239898A3 (en) * 2020-05-29 2022-01-27 Tdk Electronics Ag Electrical component comprising an electrical resistor

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3444436A (en) * 1967-04-26 1969-05-13 Erie Technological Prod Inc Mounted capacitor with spaced terminal feet
DE2601346A1 (en) * 1976-01-15 1977-07-21 Siegert Widerstandsbau Kg Plate shaped resistor element - has soldering tags projecting beyond its edge, and is mounted vertically on circuit board
US4346429A (en) * 1980-07-09 1982-08-24 Union Carbide Corporation Multilayer ceramic capacitor with foil terminal
DE3332287A1 (en) * 1983-09-07 1985-03-21 Ernst Roederstein Spezialfabrik für Kondensatoren GmbH, 8300 Landshut Capacitor of chip construction
EP0398811A2 (en) * 1989-05-18 1990-11-22 Fujikura Ltd. Manufacturing method for a PTC thermistor
US5153805A (en) * 1988-06-06 1992-10-06 Thermo-O-Disc, Incorporated Temperature-compensated thermal protector
EP0760521A2 (en) * 1995-08-29 1997-03-05 Emerson Electric Co. PTC device for protecting electrical devices
US5726623A (en) * 1994-03-01 1998-03-10 Bowthorpe Components Limited Thermistor mounting arrangement
US5867895A (en) * 1995-06-30 1999-02-09 U.S. Philips Corporation Method of mounting an electrical component with surface-mountable terminals

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3444436A (en) * 1967-04-26 1969-05-13 Erie Technological Prod Inc Mounted capacitor with spaced terminal feet
DE2601346A1 (en) * 1976-01-15 1977-07-21 Siegert Widerstandsbau Kg Plate shaped resistor element - has soldering tags projecting beyond its edge, and is mounted vertically on circuit board
US4346429A (en) * 1980-07-09 1982-08-24 Union Carbide Corporation Multilayer ceramic capacitor with foil terminal
DE3332287A1 (en) * 1983-09-07 1985-03-21 Ernst Roederstein Spezialfabrik für Kondensatoren GmbH, 8300 Landshut Capacitor of chip construction
US5153805A (en) * 1988-06-06 1992-10-06 Thermo-O-Disc, Incorporated Temperature-compensated thermal protector
EP0398811A2 (en) * 1989-05-18 1990-11-22 Fujikura Ltd. Manufacturing method for a PTC thermistor
US5726623A (en) * 1994-03-01 1998-03-10 Bowthorpe Components Limited Thermistor mounting arrangement
US5867895A (en) * 1995-06-30 1999-02-09 U.S. Philips Corporation Method of mounting an electrical component with surface-mountable terminals
EP0760521A2 (en) * 1995-08-29 1997-03-05 Emerson Electric Co. PTC device for protecting electrical devices

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021239898A3 (en) * 2020-05-29 2022-01-27 Tdk Electronics Ag Electrical component comprising an electrical resistor

Also Published As

Publication number Publication date
NL1018807C2 (en) 2003-02-25

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