CS3844

CS2844, CS3844, CS2845, CS3845 Current Mode PWM Control Circuit with 50% Max Duty Cycle The CS3844/45 provides all the necessary features to implement off–line fixed frequency current–mode control with a minimum number of external components. The CS3844 family incorporates a new precision temperature–controlled oscillator to minimize variations in frequency. An internal toggle flip–flop, which blanks the output every other clock cycle, limits the duty–cycle range to less than 50%. An undervoltage lockout ensures that VREF is stabilized before the output stage is enabled. In the CS2844/CS3844 turn on occurs at 16 V and turn off at 10 V. In the CS2845/CS3845 turn on is at 8.4 V and turn off at 7.6 V. Other features include low start–up current, pulse–by–pulse current limiting, and a high–current totem pole output for driving capacitive loads, such as gate of a power MOSFET. The output is low in the off state, consistent with N–channel devices. Features Optimized for Off–Line Control Temp. Compensated Oscillator 50% Max Duty–Cycle Clamp VREF Stabilized Before Output Stage Is Enabled Low Start–Up Current Pulse–By–Pulse Current Limiting Improved Undervoltage Lockout Double Pulse Suppression 1.0% Trimmed Bandgap Reference High Current Totem Pole Output http://onsemi.com MARKING DIAGRAMS 8 8 1 8 1 14 1 16 1 DIP–8 N SUFFIX CASE 626 SO–8 D SUFFIX CASE 751 CSx84yN AWL YYWW 1 8 384yD ALYW SO–14 D SUFFIX CASE 751A 1 14 CSx84yD14 AWLYWW 1 16 SO–16L DW SUFFIX CA...