Groomed for military and aerospace electronics, BI Technologies offers a series of custom thin-film resistor networks in hermetically-sealed metal or high-temperature cofired ceramic (HTCC) packages. The Model 144 Series high-reliability resistor networks offer custom schematics, non-standard resistance values, and ultra-tight resistance and TCR tolerances. For example, the company can achieve ratio tolerances between individual resistors in the network to less than ±0.01% and TCR tracking tolerances to less than ±1ppm/°C. Available in hermetically-sealed, through-hole DIPs and surface-mount flatpack packages with three to 28 pins, the Model 144 Series networks also employ a proprietary passivation coating over their nichrome resistive elements to protect against humid environments. Additionally, the package cavity is filled with inert nitrogen. Other features include resistance values from 10Ω to 3 MΩ, tolerances down to ±0.025% (ratio tolerances to ±0.01%), and ratio values up to 1:1000. Typical TCRs are ±25 ppm°/C with tracking between resistors available to ±1 ppm/°C. Operating temperature range is from -55°C to +175°C. BI TECHNOLOGIES, Fullerton, CA. (714) 447-2759.