Xicor Inc. (Milpitas, CA) launched its X9470 chip for biasing RF power amplifiers in cellular base stations and correcting automatically for errors related to time, temperature and other system-level effects. The X9470 is the first of Xicor's Odin architecture for adaptive closed-loop control.
The architecture on which the chip is based has a precision input stage consisting of an instrumentation amplifier and a low-pass filter. Signals as low as 50mV are detectable in a 30V common-mode signal with one-percent accuracy over temperature. The input signal is amplified, then compared with a programmable voltage reference. The value of the input voltage relative to the programmable reference increments or decrements the programmable bias voltage source. Small changes in the input-error signal increment or decrement the output drive and close the loop.
The chip supports full-static and dynamic auto-biasing of LDMOS transistors in RF power amps. Temperature compensation and alarm functions lower component count and cost for cellular base station designs, and improve system reliability by providing advanced warning of shutdown events.
In quantities of 100,000, Xicor's X9470 chip costs $4 to $8.
