Digitally gain controlled linear high voltage amplifier for laboratory applications

The design of a digitally gain controlled high-voltage non-inverting bipolar linear amplifier is presented. This cost efficient and relatively simple circuit has stable operation range from dc to 90 kHz under the load of 10 kΩ and 39 pF. The amplifier can swing up to 360 V(pp) under these conditions and it has 2.5 μs rise time. The gain can be changed by the aid of JFETs. The amplifiers have been realized using a combination of operational amplifiers and high-voltage discrete bipolar junction transistors. The circuit details and performance characteristics are discussed.