Monolithic ICs

A series of MOS monolithic integrated circuits (MOSMICs) that will allow designers to upgrade the performance of UHF and VHF tuners at no additional cost has been announced by Vishay Intertechnology. Serving as a low-noise RF input stage, the 'X' devices provide improved automatic gain control and cross modulation behaviour compared with previous-generation MOSMICs.

Six MOSMIC devices, each available in three surface mount package types, have been released, offering designers a choice of typical transadmittance specifications from 24 mS to 40 mS.

All six high-gain (>20 dB at 800 MHz) devices feature integrated protection diodes and an on-chip biasing network, eliminating the need for a number of external passive components. And since MOSMICs can be switched off directly by the PLL in tuner circuits, external switching transistors can be eliminated as well.

AGC performance has been improved to provide greater linearity. Compared with previous generation MOSMICs, Gate 1 input capacitance has been reduced by a third. All six devices feature a low 1.3 dB noise figure up to 800 MHz.

Cross-modulation has been optimised by means of an on-chip control circuit that is unaffected by the voltages applied to the gate. The minimum Xmod level is 100 dBµV at a 40 dB AGC.