June 3 , 2009 – This month’s pitch pack will discuss Stackpole’s broad line of thick film and thin film based chip resistors with power ratings that are higher than the standard EIA power ratings. As customers seek to downsize or add functions to their designs these series will be critical to their success. This pitch pack will discuss the RMCP, RHC, and RNCP series and will define which customers and applications would likely choose one series over another.
RMCP High Power Thick Film Chips
The RMCP series is a thick film based series of high power chips. This series offers a broad range of sizes from 0402 up to 2512. The higher power rating is achieved with higher performance thick film materials and more tightly controlled processes. This series would be the choice for low cost general purpose applications that require the moisture withstanding capabilities that thick film resistive elements can provide. End products for the RMCP are as varied as those for any chip resistor ranging from the most technologically advanced handheld PDA / Cell phone / MP3 player to robust industrial motor controls; this product can be valuable for literally any electronic or electrical device with a battery or power cord. From a cost standpoint the RMCP is between the RHC and the RNCP and varies with size tolerance and resistance value. Typical pricing can range from $8.75 per thousand to $225 per thousand in full reel quantities.
RHC High Power Thick Film Chips With Low Self Heating
The RHC series is a high performance high power thick film chip resistor. It is available in only the 2512 size. This series utilizes unique design, materials, and manufacturing processes to achieve better performance than other 2512 size solutions. First, the RHC is designed with larger solder pads on the bottom of the part. This larger electrical connection along with the corresponding larger solder pad on the circuit board allow much more thermal energy to be transmitted away from the part and into the board and ambient air. Second, the passivation is different than a standard part in that it is better at releasing the heat generated by the part to the ambient air; standard thick film chip passivation tends to hold in the heat. Finally, the laser trim process for calibrating the part to its desired resistance value reduces the hot spot by spreading it out more evenly across the entire resistive element. The end result of these unique features is that the continuous power handling capability of the RHC will outperform any other thick film chip resistor of comparable size. Applications for the RHC range from power supplies and power control, industrial and motor controls, network infrastructure and many other types of communications equipment, UPS systems, medical power, medical monitoring equipment, instrumentation, aircraft and aerospace, measurement equipment, lighting and ballast, logic circuitry, audio equipment, optical sensors and systems, printers and computer peripherals, hard disk drives, fluid dispensing equipment. The RHC2512 pricing varies with tolerance and resistance value and ranges from $200 per thousand to $350 per thousand in full reel quantities.
RNCP Low Cost Anti-Sulfur High Power Thin Film Chips
The RNCP is one of most exciting additions to the Stackpole product high power chip product group. This product is thin film based, so it has all of the inherent benefits usually found in thin film technology such as high stability, low noise, and high reliability. However, the RNCP is manufactured in a high-speed, low-cost manufacturing environment and using unique materials. By limiting the TCR requirements to 100 ppm and tolerance requirements to 1% and up, the RNCP pricing is within 10% of standard thick film chip pricing, a price level previously thought impossible for thin film devices. The RNCP inner termination is Nichrome instead of Palladium Silver which makes the part impervious to Sulfur contamination. This series is also a more “green” alternative to other chip resistors because it doesn’t use lead containing glass dielectric. Applications include automotive ABS, airbag, and engine controls due to its robust anti-sulfur characteristics; audio and video equipment due to its low noise; PC, laptop, and palmtop computers because of its low TCR and tolerance and high power rating; printers, scanners, and test instruments due to its high accuracy, low TCR and low cost; power supplies and radio base stations due to its high power handling and anti-sulfur performance.
The RNCP is available in 0402 through 1206 sizes, in 1% tolerances and higher, and in 100 ppm TCR. Resistance value ranges from 1 ohm to 330K ohms. Pricing varies with size and tolerance and ranges from $2.00 per thousand to $12.50 per thousand in full reel quantities.
Data Sheets for all are available at: www.seielect.com