General Descriptions
The STR2A100 series are power ICs for switching power supplies, incorporating a power MOSFET and a
current mode PWM controller IC in one package. Including a startup circuit and a standby function in the
controller, the product achieves low power consumption, low standby power and high cost-effectiveness power
supply systems with few external components.

Features and Production lineup
Features and benefits include the following
• DIP8 package, connecting one side (pin5 to pin8) with a power MOSFET drain.
The distance between high voltage terminal and low voltage terminal is 0.762mm (0.3inches), and the wider
drain trace is available to enhance thermal dissipation of the IC.
• Current Mode PWM control
• Built-in Random Switching Function, reducing EMI noise, and simplifying EMI filters, by the slight random
change of PWM frequency, fOSC.
• Auto Standby Function (Input Power, PIN < 25mW at no load)
Normal load operation ----------- PWM mode
Light load operation -------------- Standby mode (Burst oscillation)
• Built-in Audible Noise Suppression Function for standby mode
• Built-in Startup Circuit, reducing power consumption in standby operation, and eliminating external
components.
• Bias Assist Function, improving startup operation, suppressing VCC voltage drop in operation, and allowing
use of smaller VCC capacitor.
Soft Start Function, reducing stress of a power MOSFET and secondary rectifiers at startup
• Built-in Leading Edge Blanking Function
• Built-in Slope Compensation Function, avoiding subharmonic oscillation.
• Two Chip Structure, with a controller and a power MOSFET guaranteed Avalanche Energy which is available
to simplify surge absorber circuits
• Protection Functions
−Overcurrent Protection Function (OCP) ------------------Pulse-by-pulse, built-in compensation circuit to
minimize OCP point variation for AC input voltage
−Overload Protection Function (OLP) ----------------------Auto restart, built-in delay timer to reduce temperature rise
−Overvoltage Protection Function (OVP) -------------------Shutdown with latch mode
−Thermal Shutdown Protection Function (TSD)-----------Shutdown with latch mode