The A3992 is a complete microstepping motor driver with serial interface and outputs rated at ?1.5 A and 50 V. The A3992SB-T has the same pin- out and serial port control as the A3972SB-T so it can drop in to most of the A3972 applications. According to Allegro's press release, by switching to the A3992, customers receive overcurrent protection and the option to switch to a thermally efficient surface-mount version, A3992SLP-T. The A3987 is a complete PWM microstepping motor driver with built-in translator and output ratings of 50 V and 1.5 A. It is designed to operate bipolar stepper motors in full-, half-, quarter- and sixteenth-step modes. It combines an easy-to-use STEP and DIRECTION interface with a small eTSSOP package, efficient high current output,high-resolution microstepping control and overcurrent protection (OCP). The A3987 is part of the family of stepper motor drivers that includes the A3967, A3977, A3979, A3980, A3982, A3983 and A3984. Its higher voltage rating extends the family into applications that require 50 V.