UC3843 Current Mode PWM Controller IC DIP-8 Package

The UC3843 series of control integrated circuits provide the features that are necessary to implement off-line or DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components. The internally implemented circuits include an undervoltage lockout (UVLO), featuring a start-up current of less than 1 mA, and a precision reference trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator that also provides current-limit control, and a totem-pole output stage that is designed to source or sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in the off state. It offers a variety of package options, temperature range options, choice of maximum duty cycle, and choice of turnon and turnoff thresholds and hysteresis ranges. Devices with higher turnon or turnoff hysteresis are ideal choices for off-line power supplies, while the devices with a narrower hysteresis range are suited for DC-DC applications. The UC3843 is specified for operation from 0°C to 70°C. Features:- Optimized for Off-Line and DC-to-DC Converters Low Start-Up Current (< 1 mA) Automatic Feedforward Compensation Pulse-by-Pulse Current Limiting Enhanced Load-Response Characteristics Undervoltage Lockout With Hysteresis Double-Pulse Suppression High-Current Totem-Pole Output Internally Trimmed Bandgap Reference Up to 500-kHz Operation Error Amplifier With Low Output Resistance Specification:- Parameter Value Part number UC3843 Topology Boost, Buck, Buck-Boost, Flyback, Forward Control method Peak Current Mode VCC (Min) (V) 8.4 VCC (Max)(V) 28 Frequency (Max) (kHz) 500 UVLO thresholds on/off (V) 8.4/7.6 Duty cycle (Max) (%) 100 Gate drive (Typ) (A) 1 Features Adjustable Switching Frequency, Current Limiting, Dead Time Control, Error Amplifier, Multi-topology Operating temperature range 0 to 70 Package Group PDIP|8 Package size: mm2:W x L (PKG) 8PDIP: 93 mm2: 9.43 x 9.81 (PDIP|8) Related Document:- UC3843 IC Datasheet