Toshiba’s TB67S531FTG Targets Noise-Prone Stepper Motor Designs
A phase-input interface aims to keep bipolar stepper drives synchronized when industrial equipment gets electrically noisy.
Toshiba Electronics Europe has launched the TB67S531FTG, a constant-current, two-phase bipolar stepper motor driver IC built around a phase input interface rather than the clock-driven translator scheme common to many competing drivers. Toshiba positions the part for industrial, commercial, and office gear that tends to run in electrically noisy environments, including sewing machines, surveillance cameras, printers, and scanners.
A Different Path to Fending Off Step-Out
Where many bipolar stepper drivers advance the electrical angle from a single clock line and internal translator logic, the TB67S531FTG instead accepts phase current commands directly, setting the current level in each phase explicitly rather than inferring it from a step sequence. Toshiba’s stated rationale is that this arrangement narrows the opportunities for unintended step transitions when a clock edge or mode line is corrupted by electrical noise. It’s a meaningful distinction for engineers weighing input schemes: clock-driven translators, as found in comparable 36V-class bipolar drivers, simplify the controller-side logic but hand step integrity over to the noise immunity of a single input pin. Toshiba’s approach shifts some of that responsibility back into the phase current path itself.
Efficiency and Protection in a Small Footprint
The TB67S531FTG is rated for motor output voltages up to 40V and continuous phase currents up to 2.0A, with a typical on-resistance of 0.8Ω that Toshiba credits with lower heat generation and improved thermal margin under sustained load. Integration works in the driver’s favor: a current detection circuit provides internal constant-current regulation, and a charge pump supplies the gate drive for the H-bridge output stage, reducing the external component count compared with a discrete solution. All of this fits inside a 5.0mm × 5.0mm QFN32 package, a size that should ease layout in space-constrained equipment. Rounding out the safety picture, the device includes thermal shutdown, over-current detection, and under-voltage lockout, the same trio of protections found on many rival bipolar stepper drivers, giving designers a familiar fault-handling baseline to build around.
Multi-function printers and scanners often share power rails with motors and switching supplies, the kind of setting the TB67S531FTG targets. Image used courtesy of Adobe Stock
Excitation Flexibility Across Applications
Beyond the input scheme, the TB67S531FTG supports multiple excitation modes spanning full-step through quarter-step operation, allowing a single design to dial in the torque, resolution, and vibration characteristics that suit its mechanism without swapping silicon. That range mirrors what’s available in other bipolar stepper drivers on the market, where full-step modes tend to favor higher torque and quarter-step modes favor smoother, quieter motion at the cost of more complex current waveforms.
Taken together, the phase input interface, integrated current sensing, and compact QFN32 footprint make the TB67S531FTG a tidy option for equipment designers who need reliable step control near motors, solenoids, or switching power supplies that inject electrical noise into a board. Sewing machines, multifunction printers, scanners, and security cameras all fit that description, and the part’s excitation flexibility means it could just as easily find a home in smaller robotics or automation gear where both smooth motion and rock-solid step accuracy matter.
