The TC78S121FNG from Toshiba is a PWM Chopper Type Dual-Stepping Motor Driver IC that is designed to perform bipolar stepping motor control operations. It has an input voltage of 8-38 V and an output current of 1.5 A. This dual-stepping motor driver is a single-chip-based driver IC that integrates two-stepping motor drivers that are capable of driving up to four brushed DC motors. It also incorporates two pairs of H-bridge drivers that can drive two DC motors or a single stepping motor at a time.

This TC78S121FNG is based on a silicon monolithic configuration that is manufactured based on the CD process. It internally connects a Vcc regulator for internal circuit operation, thereby eliminating the need for an external power supply. This motor driver IC uses an external capacitor and a resistor to set the chopping frequency and provides an option to enable high-speed chopping. It utilizes over-current detection (OSD), thermal shutdown (TSD), and power-on reset circuitries to prevent short-circuit-related damages. This RoHS-compliant motor driver IC is available in a surface-mount package that measures 12.5 x 8.1 mm and is ideal for commercial applications.