The circuit shown in the figure is suggested by Microchip (www.microchip.com), being built around the operational amplifiers MCP6291 / 1R / 2/3/4/5. These are 1 mA, 10 MHz operational amplifiers, rai-to-rail with a 10 MHz pass-through product. The supply current is 1mA, and they operate with voltages from 2.4 to 6.0 V.
