An exemplary electronic actuator assembly is configured for use with a pushbar assembly having a drive assembly operable to retract a latchbolt, and includes an input shaft, a motor, and a boost spring. The motor has a retracting state in which the motor drives the input shaft from a proximal position to a distal position, a holding state in which the motor exerts a holding force to retain the input shaft in the distal position, and a releasing state in which the motor exerts a residual force that resists movement of the input shaft. The boost spring exerts a boost force urging the input shaft in the proximal direction to at least partially counteract the residual force.