What the SG3524N is and where it fits
The Texas Instruments SG3524N is a pulse-width modulation (PWM) control IC designed for a wide range of DC-DC converter topologies. It handles step-up, step-down, and step-up/step-down configurations, supporting buck, boost, flyback, forward converter, full-bridge, half-bridge, and push-pull designs. The part integrates the oscillator, error amplifier, reference, and dual transistor drivers on a single die, making it a self-contained controller for isolated and non-isolated supplies up to 450 kHz switching frequency. The 16-pin DIP through-hole package (16-PDIP) suits prototyping, legacy board repairs, and designs where wave-solder assembly is preferred over surface-mount. The 0°C to 70°C commercial temperature grade limits the part to indoor, climate-controlled environments — not for automotive under-hood or outdoor telecom cabinets without active thermal management. Control features include current limiting and frequency control, giving the designer basic loop compensation without external timers. The output configuration is positive and isolation-capable, so the SG3524N can drive a transformer in flyback or forward topologies with optocoupler feedback on the secondary side.
45% duty cycle — the topology gate
The maximum duty cycle per output is 45%.
450 kHz switching — magnetics sizing trade-off
The maximum oscillator frequency is 450 kHz.
Supply range and output drive
The 8V to 40V supply range covers unregulated rectified AC (e.g., 12V or 24V nominal rails) and industrial bus voltages. The two transistor-driver outputs each source and sink enough current to drive a power MOSFET gate directly for low-to-medium power levels. For higher gate charge, an external driver stage is advisable.
Lifecycle and sourcing
The SG3524N is listed as Active and ROHS3 compliant. For volume production or BOM freeze, the active status means no imminent LTB risk.