Tuning Varactor Diodes
The hyperabrupt series (GVD1400, GVD20400 and GVD20430) silicon tuning varactor diodes feature a variety of capacitance ratios: the GVD1400 series models are suitable for broadband applications up to VHF, the GVD20420 models are suitable for VHF and UHF frequencies, and the GVD20430 models are suitable for UHF frequencies and higher. The GVD302 super hyperabrupt series tuning varactor diodes have a linear characteristic and an extremely high capacitance swing and are designed specifically for 3 and 5 V-powered circuits. Device dissipation (at 25°C) is 250 mW for all models. Junction temperature is 125°C and operating temperature is –55° to 125°C. The devices are available in SOT-23 and SOD-323 surface-mount packages or in chip form. Delivery: two weeks (ARO). Prices: start at $1.03.
Sprague-Goodman Electronics Inc.,
Westbury, NY
(516) 334-8700.

Custom Chip Arrays
The models 1206 and 2512 chip arrays are now available in custom versions. Resistance values of 10 W to 1 MW can be combined in various networked configurations of four and nine resistors. The chips’ versatility allows board manufacturers to simplify board layouts, reduce component count and enhance circuit performance. Networks can be manufactured with up to two resistance films on each chip, allowing a greater range of resistance to be specified. The model 1206 chip features a maximum allowable resistance ratio in each film of 2:1; the model 2512 chip features a maximum allowable resistance ratio of 4:1. The tolerance on resistance values and the ratio tolerance is between +/-1 and +/-5 percent. Maximum power dissipation per resistor is 63 mW and the tempco is either 100 or 200 ppm/°C with temperature coefficient of resistance tracking of 50 ppm/°C for one resistor film.
BI Technologies,
Fullerton, CA
(714) 447-2300.