UC3842B

UTC UC3842B / 3843B LINEAR INTEGRATED CIRCUIT HIGH PERFORMANCE CURRENT MODE CONTROLLERS DESCRIPTION The UTC UC3842B/3843B are specifically designed for Off-Line and dc-to-dc converter applications offering the designer a cost-effective solution with minimal external components. The UC3842B has UVLO thresholds 16V (on) and 10V(off), ideally suited for off-line converters. The UC3843B is tailored for lower voltage applications having UVLO thresholds of 8.5V(on) and 7.6V(off). SOP-8 FEATURES *Trimmed Oscillator for Precise Frequency Control *Oscillator Frequency Guaranteed at 250kHz *Current Mode Operation to 500kHz *Automatic Feed Forward Compensation *Latching PWM for Cycle-By-Cycle Current Limiting *Internally Trimmed Reference with Undervoltage Lockout *High Current Totem Pole Output *Undervoltage Lockout with Hysteresis *Low Startup and Operating Current DIP-8 BLOCK DIAGRAM UTC UNISONIC TECHNOLOGIES CO., LTD. 1 QW-R103-012,A UTC UC3842B / 3843B LINEAR INTEGRATED CIRCUIT ABSOLUTE MAXIMUM RATINGS(Ta=25°C) PARAMETER Total power supply and Zener current Output current, source or sink (note1) Output energy (capacitive load per cycle) Current sense and voltage feedback inputs Error Amp. Output sink current Power dissipation and thermal characteristics Operating junction temperature Operating ambient temperature Storage temperature range SYMBOL (ICC + Iz) Io W Vin Io PD PθJA Tj TA Tstg VALUE 30 1.0 5.0 -0.3 ~ +5.5 10 SOP: 702 SOP: 178 +150 0 ~ +70 -65 ~ +150 UNIT mA A µJ V mA mW °C/W °C °C °C DIP:1250 DIP: 100 ELECTRICAL CHARACTERISTICS (0°C