A wide-band, low-power, high slew rate voltage-feedback operational amplifier

A wide-band low-power voltage-feedback operational amplifier on a 3 GHz, 40 V complementary bipolar technology is described. The class AB input stage takes advantage of some current-boost transistors which enhance and linearize the slew-rate during large-signal operation without increasing the power consumption. The triple-buffered output stage provides 100 mA of load current maintaining good linearity. Since the circuit design and technology development were concurrent, several different circuits were stepped into one wafer to fully characterize the process and identify the best product candidates. The low-current version of this chip has a quiescent current of 2.5 mA, 2000 V/μs slew rate and gain bandwidth of 110 MHz. The medium-current version draws only 6.5 mA of current at the same supply voltage while the slew rate increases to 3500 V/μs and bandwidth to 210 MHz. Both parts are operational from +/-2.75 V to +/-18 V supply range. Die size is 51 mils by 76 mils on a poly-emitter CB process