TECHNOLOGY ROUNDUP

Passives Provide Protection, Suppression, Detection and Decoupling

This issue’s technology roundup focuses on passive components: Positive Temperature Coefficient (PTC) thermistors from EPCOS; low Equivalent Series inductance (ESL) capacitors from Murata; Panasonic’s range of compact RFI suppression capacitors; and Vishay’s expanded family of extended temperature range and highly compact SM current-sensing resistors.

PTC thermistors from EPCOS provide reliable and cost-effective solutions in a wide variety of applications. They are used, for example, as resettable fuses in telecommunications equipment and power supplies, as temperature and level sensors and for temperature compensation in LED applications. PTCs in space-saving SMD sizes are gaining importance in many fields and EPCOS is expanding its portfolio with even smaller SMD sizes and further reduced response time.



Features

• Thermally sensitive resistors
• Reference temperature down to just ±3°C
• 0402 sensor series now available
• Ceramic and wired PTC resettables
• Continuous operation to 265V
• Telecom Pair Protector featuring 2x PTCs available

As microprocessors continue to increase in speed, so the need grows for chip capacitors with low Equivalent Series inductance (ESL) for decoupling purposes. Murata’s evolving range of low-ESL capacitors is designed to suit a wide variety of high-frequency IC applications, not simply keeping up with these requirements but consistently exceeding them. The company has announced a number of recent additions to its LLL, LLA, LLM and LLK series of low-ESL capacitors, extending the capacitance ranges over standard and extra-low-profile versions, while keeping ESL especially low.



Features

• Low-ESL decoupling capacitors
• Range of ESL options
  • 150pH to 250pH range
  • 80pH to 120pH range
  • 45pH range
  • Sub-45pH options
• Suitable for a variety of clock speeds
  • 120MHz to 800MHz
  • 800MHz to 2GHz
  • 2GHz to 3GHz
• Range of form factors
  • Standard and extra-low-profile versions
  • 0204, 0306, 0508, 0603, 0612, 0805, 1206
• X7S dielectric versions
• Capacitance values up to 10µF
• Tape and reel packaging
• RoHS compliant

Panasonic provides a wide range of compact interference suppression film capacitors, which are mainly used to suppress RFI transients. Their primary function is in power supply applications which are permanently connected to the mains electricity supply, where they occupy the line-to-line (X) position and, in particular, the IEC-defined X2 role. These devices are available in standard lead-wire spacings of 15mm, 22.5mm and 27.5mm, giving great flexibility for redesigns if necessary. All devices are RoHS compliant.



Features

• Miniature X2 capacitors for RFI suppression
• Flame-retardant plastic case
• Incombustible resin
• Built-in safety mechanism
• Wide capacitance range: 0.001µF to 2.2µF
• Low dissipation factor: 1.0% maximum
• Self-healing ability
• Standards compliant
• RoHS compliant
• Lead spacings 15mm, 22.5mm and 27.5mm

Vishay Intertechnology has extended its range of surface-mount current-sensing resistors with two new products. The new Power Metal Strip devices are the WSLT2512, for use at high temperatures of up to 275°C, and the WSLP1206, believed to be the industry’s first such device in the very small 1206 package size to be rated at 1W. Both devices are manufactured using proprietary techniques that result in extremely low resistance values, tight tolerance and low TCR values.



Features

• Small form factor 1W current-sensing resistors
• High-temperature handling up to 275°C
• Extremely low resistance values
  • 10mΩ to 500mΩ (WSLT2512)
  • 1mΩ to 50mΩ (WSLP1206)
• Tight tolerance down to ±0.5%
• Low TCR values down to ±75ppm/°C
• All-welded construction
• Solid metal resistive element: nickel-chrome or manganese-copper (WSLT1206 only)
• Low inductance: 0.5nH to 5nH (WSLP1206); less than 5nH (WSLT2512)
• Excellent frequency response to 50MHz
• Low thermal EMF: less than 3µV/°C

For further information, including Datasheets for featured products, please click here