Patent ID: 7453307

Claim:
A process independent voltage controlled logarithmic attenuator comprising: a maximum gate voltage generator; an amplifier having a first input coupled to a controlled input and a second input coupled to an offset generator, wherein a positive power supply of the amplifier is coupled to the maximum gate voltage generator, a maximum output of the amplifier being approximately equal to a voltage of the maximum gate voltage generator; an attenuator transistor coupled to the maximum gate voltage generator and to an output of the amplifier; a resistive element coupled the attenuator transistor and to an attenuator output terminal; and an input resistive element coupled to an attenuator input and to the resistive element; wherein a minimum on-resistance of the attenuator transistor is proportional to a maximum gate voltage generator resistive element, the maximum gate voltage generator resistive element having a same structure of the resistive element coupled the attenuator transistor so the logarithmic attenuator is process, temperature and supply independent.