The 8I20 is a low cost 2200W 400V three phase torque mode amplifier for synchronous permanent magnet servo motors (Brushless AC servo) up to approximately 3HP. The 8I20 will supply peak currents of 30A. High side logic and gate power are derived from the low side allowing a wide operational bus voltage range (24 to 400VDC) and host communication when bus voltage is off. Low side power can be 5V +-5% or 7-48V unregulated. 3750V RMS isolation is provided between high and low side electronics. Hall effect current sensing is used along with high speed bus voltage monitoring for an accurate, stable, and fast current/torque control loop. High side over current sensing protects the IGBT module from line-line and line-ground faults. A brake output capable of 15A drive is provided. The brake output can be driven at a presettable overvoltage setting. Even though it uses a 40 Mips DSP, the 8I20 is a 'dumb' amplifier suitable for integration in host based motion control systems. The 8I20 requires reference angle and requested current/torque values sent from a host controller. The 8I20 uses the requested torque and reference angle to control the current loop. The 8I20 can echo status information to the host controller including bus voltage, phase currents, card temperature etc. The host controller may be a PC with a fast serial interface and quadrature counters or a Mesa FPGA card running SoftDMC or HostMot2 firmware. For applications that require a smart amplifier, the 8C20 daughter card can be added. The 8I20/8C20 combination adds the features of analog input velocity and torque modes, step and direction mode, quadrature input mode, smart position control mode, and four isolated inputs and outputs.