A tiny, high-speed, wide-band, voltage-feedback amplifier stable with all capacitive load

A tiny, high-speed, wide-band, voltage-feedback operational amplifier capable of driving unlimited capacitive load is described. A class AB input stage is combined with a modified dynamic Witch-Hazel current mirror to provide high slew rate and wide bandwidth with a small die area and small idle current. An RC network couples part of the capacitive load into the high-impedance node, therefore lowering the dominant pole and increasing stability as a function of capacitive load. The part was fabricated on a 3 GHz, 40 V complementary bipolar process. The quiescent current of the chip is 4.5 mA with 1500 V//spl mu/m slew rate and a -3 dB bandwidth of 235 MHz. The part is operational from /spl plusmn/2.5 V to /spl plusmn/18 V supply range. Die size is 38 mils by 46 mils and it fits into a tiny surface outline transistor (SOT) package.