Product category:
Resistors
News Release from: TT Electronics Welwyn Components | Subject: LR Series
Edited by the Electronicstalk Editorial
Team on 29 June 2004
Resistors find automotive niche
The LR Series of low-ohmic-value current-sense thick-film resistors is finding uses in the automotive sector for applications that require high power handling (3W) and low resistance (R003).
TT Electronics Welwyn Components is finding new applications for its low ohmic value current sense thick film resistor technology in the automotive sector for applications that require high power handling (3W) and low resistance (R003) From a certified supplier offering the global automotive quality standard TS16949, Welwyn's LR Series gives all round superior performance for current sensing in lamp detection, mirrors, window lift, steering and seat controls
This article was originally published on Electronicstalk on 26 Sep 2006 at 8.00am (UK)
Related stories
Current sense resistors minimise power consumption
Welwyn Components has expanded its current sense resistor offering with the launch of the ULR series, its lowest ohmic value resistor, to minimise power consumption.
Tiny resistors handle up to 3kV
The Welwyn Components HVC series of high-voltage chip resistors offers compact sized resistors rated for continuous voltages up to 3kV.
As a first instance, the LR Series displays enhanced power handling capabilities, against metal strip and other technologies.
This is due to better thermal conductivity of the ceramic and proprietary thick film construction, in contrast to nichrome or other resistance alloys used on the metal strip resistors.
Depending on the solder pad layout and operating ambient temperature, up to 2W is offered in a four-terminal (Kelvin) layout that can be dissipated in a standard 1W (2512) package, and up to 3W in the 1225 (solder pads along the edge of the part).
Further reading
Surface mount resistors take on new tasks
Welwyn Components is finding specialist new applications for its ranges of standard and custom surface mount resistors.
Stainless-steel substrates are hot stuff
Welwyn Components has further developed its thick-film technologies by offering integrated custom packaging solutions, using stainless-steel substrates.
Thanks to their small size, thermal conductivity is important for chip resistors - little heat is dissipated directly into the air, and instead, is conducted out through the solder pads.
The heat generated from the specially constructed LR resistor is more readily dispersed, therefore preventing localised heating, which contributes to TCR and thermal EMF errors, premature aging and possible scorching of the PC board.
Extended power rating is possible with the LR Series resistor, by increasing the solder land footprint.
This is an advantage not available with metal strip technology, as their low thermal conductivity makes it more difficult for generated heat to escape from the resistor.
Operating a metal strip resistor at such extended power levels would cause hot spots, significant resistance changes and reduction in reliability.
In applications where high frequency performance is demanded, the LR series, with its single computer controlled resistance value laser cut and planar construction, exhibits minimal internal capacitance and parasitic inductance.
The newest member of the LR family is the LRF3W, the industries smallest 3W current sense chip, offering rated power dissipation at up to 70C ambient in a 1225 body size.
This avoids the requirement, in higher current applications, to "neckdown" the circuit board trace at the component solder joints.
The LR family rates up to a full 3W at 70C; resistance values from 0R003 to 1R with tolerance to 1% and TCRs of 100ppm/C.
They are rated for ambient operation from -55 to +150C. Request a free brochure from TT Electronics Welwyn Components ...
• TT Electronics Welwyn Components: contact details and other news
• Email this article to a colleague
• Register for the free Electronicstalk email newsletter
• Electronicstalk Home Page
Search the Pro-Talk network of sites
