MATERIALS

Thermal Adhesive
Ablebond" 8177 adhesive is designed for applications requiring better dispensability and thermal conductivity. The adhesive provides high thermal conductivity (3 W/mK), and the rheological properties allow the epoxy to flow easily under components, making it suitable for applications such as bonding heat sinks or other heat dissipation architectures to semiconductor devices. The product also exhibits good adhesion to large areas with a thin bond line. The adhesive comprises a blend of silver particles in a high purity epoxy resin. This electrically conductive epoxy exhibits low chloride, sodium and potassium contamination levels, allowing for improved electrical reliability during environmental testing. It can be cured at a low temperature, such as 110°C for 10 minutes, or fast cured on in-line equipment at a higher temperature such as 150°C for two minutes.
Ablestik,
Rancho Dominguez, CA (310) 764-4600.

Surge Resistor Materials
The 7400 series nontoxic surge resistor materials comprise five blendable paste compositions with sheet resistance values of 100 mW/sq, 200 mW/sq, 500 mW/sq, 1 W/sq, and 3 W/sq. Also available is 7401, a new blue encapsulant that is fired at 850°C. Resistance shifts after the maximum 10/1000 pulse-type applied voltages are low (less than 0.1 percent), provided the 7401 encapsulant is used. Resistance shifts after refiring at 850°C are in the range of one to three percent, and all pastes in the series are available with temperature coefficients of resistances of less than 50 ppm/°C over the temperature range of +25° to +125°C. The 7401 encapsulant is laser trimmable at speeds above 20 mm/s and is compatible with high volume production processes.
DuPont,
Wilmington, DE (800) 284-3382.

PTFE Woven-glass Laminate
The type CER-10 ceramic-filled, polytetrafluoroethylene (PTFE) woven-glass laminate is designed for microwave and RF PCBs. The high Dk allows for circuit miniaturization and better heat dissipation for increased power-handling capability. The company’s proprietary composition results in a flat Dk over frequency (less than +0.6 percent over 10 GHz) and temperature. The laminate features interlaminar bond strength and dimensional stability (–0.0002 in/in), allowing for easy fabrication and assembly. The unit’s low moisture absorption (less than 0.02 percent) permits processing consistent with FR4 circuit materials (no pre-bake necessary).
Taconic, Advanced Dielectric Division,
Petersburgh, NY (800) 833-1805 or (518) 658-3202.

Surface-mount Transistor Package
 The Mini-Pak series surface-mount transistor package is designed for discrete packaging of the company’s model 2N2222A transistor. The packaging technique allows greater density by utilizing an encapsulation epoxy and thick-film substrate technology to miniaturize a footprint half the size of a SOT-23 outline. The package dimensions are 0.080" x 0.050" x 0.045". This encapsulant packaging technology has the flexibility to be customized for a wide variety of transistors, diodes, FETs and other applications.
Sunbelt Microelectronics Division of Mini-Systems Inc.,
Deltona, FL (407) 574-0208.

Ceramic Dielectric Material
The 4500 series ceramic dielectric material is designed for temperature-stable dielectric resonators. The material is suitable for frequency operation from 800 MHz to 13.5 GHz. With its high dielectric constant (er = 45), this material offers a reduced size while maintaining high Q and good temperature stability. Temperature coefficients of resonant frequency (tf) are available from –6 to 0 ppm/°C.
Trans-Tech, a subsidiary of Alpha Industries,
Adamstown, MD (301) 695-9400.