Programmable Cap Replaces Mechanical Inductors

Debuting as the industry's first electronically programmable capacitor, the MAX1474 has a high self-resonant frequency and is designed to replace mechanical inductors in tuning circuits. Housed in a 2.2 x 2.4 mm, SC70 package, the programmable cap can be set to any one of 32 values from 6.26 to 12.74 pF in 0.2 pF steps. Two pins are required for programming the device, which is achieved by raising the enable pin and sending a discrete number of pulses that correspond to the desired capacitance to the second pin. No clock is required, and the device will remain at the set capacitance as long as power is applied. Implemented in silicon, the component is said not to drift over time. And its temperature coefficient is less than 33 ppm/°C with a Q of 50 possible. The capacitor can also be customized for special applications. Price is $0.73 each/1,000.