What the 49% duty cycle ceiling means for your transformer
The SG3525AP is a fixed-frequency PWM controller from STMicroelectronics, built for push-pull and buck topologies where the 49% maximum duty cycle prevents flux walking in the transformer core. At 49%, the off-time guarantees core reset before the next cycle — skip the dead-time calculation on a half-bridge or push-pull design. Two complementary outputs drive the primary-side MOSFETs directly, with a transistor driver stage rated for the full 8V to 35V supply range. The 100Hz to 400kHz switching window covers line-frequency inverters at the low end and compact DC-DC converters at the high end.
Supply rails and temperature — the fit check
The 8V to 35V Vcc range lets this part run off a 12V or 24V industrial bus without a pre-regulator. Below 8V the undervoltage lockout holds the outputs off; above 35V you need a clamp or a different controller. If the board lives in a motor drive enclosure or under-hood, step to the industrial-grade SG3525A variants.
No last-time-buy notice, no end-of-life window. The 16-SOIC package (0.154-inch body width, 3.90mm) is the standard narrow-body SOIC-16 footprint.