Integrated bipolar stepper drive with microstepping
The L9942XP1TR is a fully integrated bipolar stepper motor driver from STMicroelectronics, combining the control logic and power stage in a single PowerSSO-24 package. It drives one bipolar stepper motor using four half-bridge outputs rated for 1.3 A continuous per bridge. The DMOS output stage keeps conduction losses in check — the Rds(on) at junction temperature determines the thermal budget at 1.3 A, so the 150 °C Tj max rating gives headroom for under-hood or engine-bay duty where ambient soaks above 105 °C. Microstepping resolution is programmable via SPI up to 1/32 step, which smooths low-speed torque ripple and reduces mechanical resonance in the load. The SPI interface also handles diagnostic readback — useful for detecting stall or open-winding conditions without an external sense resistor network.
Supply rails and operating envelope
The motor supply (VM) accepts 7 V to 20 V, covering nominal 12 V automotive batteries with margin for cold-crank dips and load-dump spikes within the absolute maximum.
Package, mounting, and procurement
The tape-and-reel option suits high-volume pick-and-place assembly.