This application note describes a composite amplifier made up of two or more amplifiers that can achieve high speed and DC precision simultaneously.
The document explains that practical applications often require amplifiers with both high speed and DC precision, which a single device may not provide. It details how composite designs combine two or more amplifiers to merge the best features of each for optimal performance.
Several specific circuit configurations are presented, including a basic DC-stabilized fast amplifier using an LT1012 and LT1022, wideband FET input buffers, gain-trimmable amplifiers, and high-swing inverting stages. The text provides component values, theoretical explanations of the stabilizing loops, and performance metrics such as slew rate and bandwidth for each design.
| Offset Voltage (LT1012) | 35nV |
|---|---|
| Drift (LT1012) | 1.5V/°C |
| Slew Rate (LT1022) | 23V/us |
| Full-Power Bandwidth (LT1022) | 300kHz |
| Bias Current (Figure 1) | about 100pA |
| Slew Rate (Figure 2) | exceeds 100V/us |
| Full-Power Bandwidth (Figure 2) | about 1MHz |
| Bandwidth (LT1010) | 15MHz |
| Output Current (LT1010) | 150mA |
| Full-Power Bandwidth (Figure 6) | 10MHz |
To combine the best features of two or more amplifiers to achieve performance unobtainable in a single device.
It uses an LT1012 to monitor and stabilize the DC operating point while an LT1022 handles high-frequency inputs.
The full-power bandwidth is about 1MHz.