ELECTRONICALLY PROGRAMMED CAPACITOR REPLACES MECHANICAL INDUCTORS
SUNNYVALE, CA-February 5, 2001-Maxim Integrated Products introduces the MAX1474, the industry's first electronically programmable capacitor with high self-resonant frequency and 32 discrete capacitive steps. The MAX1474 is housed in a tiny SC70 package (2.2mm x 2.4mm).
The MAX1474 is designed to replace unreliable, mechanical inductors in common tuning circuits. It can be set to any one of 32 discrete capacitive steps ranging from 6.26pF to 12.74pF in 0.2pF increments. Simple application circuits can be used to increase the capacitive range, increase capacitive steps, or to multiply the Q value to fit a particular application. Because the capacitors are actually implemented in silicon, there is virtually no drift over time and the temperature drift coefficient is less than 33ppm/°C. A Q of 50 is possible.
Only two pins are required to program the MAX1474. Capacitive values are selected by raising the enable pin and sending the MAX1474 a discrete number of pulses corresponding to the desired capacitive value. The MAX1474 does not require a clock and will retain the programmed capacitance value for as long as power is supplied. If the system is dynamic and has the ability to retune itself, the capacitance value can easily be changed at any time by simply raising the enable pin and sending the desired number of pulses.
Applications include post-trim of low-cost regenerative stages, tunable RF stages, garage door openers, keyless entry, industrial wireless control, and precision trimming of capacitive-based sensors.
Maxim can quickly customize the MAX1474 for unique requirements of high-volume applications. The MAX1474 starts at $0.73 (1000-up, FOB USA).
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