Raleigh, N.C. Touting high performance, Stackpole Electronics (formerly SEI Electronics) says its new HVD series of leaded high-voltage resistor divider networks, based on its proprietary fine film deposition process, are superior to any thickfilm resistor network technology that exists today, and touts several advantages over thin-film technology. The company believes its technology is better than traditional thickfilm counterparts, namely because of advantages in resistance value range, tolerance, voltage ratings, and temperature coefficient of resistance (TCR).
A few months ago SEI first introduced its new fine film deposition process with the launch of its HVC family of chip resistors.
By applying its proprietary fine film deposition process that enables the company to achieve highly precise resistive traces on the substrate to the new HVD line, the company is able to deliver a new level of performance. What this brings to the table in the realm of resistor dividers is plenty lower inductive noise, tighter tolerances, low TCR, higher voltage range and a wider resistance value range.
SEI's new technology appears to deliver the best of both thickfilm and thin-film technologies competitive pricing and high performance characteristics without the limitations.
Key features of the new high voltage dividers include:
- Resistance range up to 2 teraohms
- Voltage ratings up to 40,000 volts
- Tight tolerance to 0.1%
- Low TCR to 10 ppm/° C
- Low TCR tracking to 5 ppm/° C
- Low VCR to 0.05 ppm/volt
Instead of screen printing the resistive traces on a substrate, the new process uses what can be best described as a type of precision pen writing that enables much finer and closer traces to achieve tighter tolerances and TCRs, as well as lower inductive noise.
Screen printing is very imprecise, lending itself to resistive traces with jagged edges, resulting in a more noisy circuit with higher inductance and less stable resistors over time and temperature, said Rob Hudspeth, Stackpole's director of sales. "With fine film deposition, we can achieve an exact height, width and thickness of the trace at any point. It can be controlled much better than pushing ink through a screen," he said.
Typically traditional thickfilm products offer lower performance characteristics than thin-film components, and as a result come with a lower price tag, which is a key benefit for price-sensitive markets. When compared to these products, Stackpole's thickfilm technology is less noisy, more stable and offers higher performance characteristics similar to thin-film parts.
The new technology also stacks up very well against thin-film resistor networks, and offers many of the same characteristics ultra-high stability, tight tolerances and very low noise without the high price tag for a premium device.
Although thin-film technology, known for its precision performance, still offers tighter resistance ratio tolerances and lower TCRs, the new technology supplies higher performance in some areas. Thin-film technology has limitations in ohmic range, and offers limited resistance values and ratios between resistors, which is not the case with fine film deposition technology.
The key advantage of using the precision film deposition process for the HVD series is the wide resistance range up to two teraohms as well as the resistance ratio of up to 20,000:1, which is virtually unheard of in the industry, Hudspeth said.
In addition, it offers TCR tracking between thickfilm resistors at 10 ppm/°C with absolute TCR tracking at ±25 ppm.
Better precision is always important, and a 25-ppm absolute TCR and 10-ppm tracking is twice as good as any thickfilm spec on the market, said Kory Schroeder, product engineering manager for Stackpole. While thin-film dividers can achieve similar if not better precision, it's at a greatly reduced resistance value range and typically at a much higher cost, he said.
As for power ratings, they will vary greatly depending on the choice of resistance value, termination and operating temperature, Shroeder said. They can be as low as .25 watts at 70°C to 6 watts at 25°C.
Key applications include telecommunications equipment, measurement and control, medical devices and instrumentation. One standout application for the new dividers is in telecom circuitry as a line feed resistor for lightening strikes and/or power crosses, where all the performance characteristics high ohmic values, high stability, high voltage ratings, tight ratio tolerance and low noise are all very important for this application, Hudspeth says.
Available in standard package sizes of ½ inch up to four inches in length with a height of .375 inches up to .75 inches, these devices are built to customer specific power and voltage ratings. Currently, these devices will not be available in standard values; however, there may be a point in the future where the company may develop standard parts at each power level for specific ratios for sampling or for off-the-shelf requirements.
Pricing starts at approximately $2.00 each in quantities of 2,000. In low volume, some devices will run $4 to $5 each. Engineering samples are available in four weeks.
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