Low Power Current-Mode Second-Order

A controlled active inductance implemented from two current-controlled conveyors in conjunction with one capac- itor is introduced. Calculation, taking all the parasitics of the conveyors into account, shows that with this design the phase deviation from ideal is pushed up to very high frequency. A second order bandpass filter operating in current-mode has been implemented from this controlled inductance. This filter exhibits two bandpass outputs. One has unity gain and the other, which can be used for -tuning purpose, has a magnitude-gain at directly proportional to the -factor. An integrated circuit prototype of an IF receiver stage for the GSM cellular telephone has been designed from two cascaded identical second-order bandpass cells above. This circuit, which is intended to replace a surface acoustic wave (SAW) filter, was centered at 85 MHz. Simulation and measurement results are given for this prototype. They show interesting performances in conjunction with very low power consumption: less than 38 mW for the entire IF stage under 2.5 V supply.