The XL4s linear amplifier is designed for closed-loop servo control of voice coil and single-phase motors, eliminating the nonlinearities common with PWM amplifiers. It provides deterministic behavior, auto-identification and easy software setup and features a multi-core, double-precision, floating-point DSP that controls the digital PID. All parameters are software-settable, including control-loop gains and system safety functions. The amplifier achieves long-term thermal stability and sub-micron-level tracking accuracy with advanced features such as full-state feed-forward, 192-kHz servo rates and look ahead-based velocity control. It also has an encoder interpolation feature, dedicated analog and digital I/O, fiberoptic interface and separate power connections for motor and control supply voltages.