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