SI-7321M

Product Information SI-7321M Motor Driver IC Introduction This document describes the function and features of SI-7321M, a unipolar 2-phase stepping motor driver IC. This device uses PWM constant current-control, and provides user-configurable sequencer parameters. The clock-in type input interface allows simplified control logic, and options for built-in sense current detection and load circuit short or open protection (patent pending) provide lower loss. Lower thermal resistance results from the innovative multi-chip internal structure, which separates the main control IC (MIC) from the four heat-generating MOSFETs, and places wide output terminals at package corners to enhance thermal dissipation. The built-in excitation distribution circuit (sequencer) allows motor control using only the Clock signal for simple operations (forward, reverse, brake, coast, hold), with motor speed control by frequency input into Clock pin, and rotation direction control by a dedicated logic input. This eliminates logic signal lines required for conventional phase-input methods, and reduces demand on heavily-used CPUs. Features and benefits include the following: ▪ Power supply voltage, VBB , 46 V maximum, 10 to 44 V normal operating range ▪ Logic supply voltage, VDD , 3.3 to 5.5 V ▪ Maximum output current: 1.5 A ▪ Four NMOS output MOSFETs, RDS(on) = 0.25 Ω typical ▪ Built-in sequencer ▪ Simplified clock-in stepping control ▪ Full- and half-stepping and 1/4 , 1/8 , and 1/16 microstepping ▪ S...