UC2843AN

Product Summary

The UC2843AN is a high performance fixed frequency current mode controller which is specifically designed for off–line and dc–to–dc converter applications offering the designer a cost effective solution with minimal external components. The UC2843AN features a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle–by–cycle current limiting, programmable output deadtime, and a latch for single pulse metering. The UC2843AN is available in an 8–pin dual–in-line plastic package as well as the 14–pin plastic surface mount (SO–14). The SO–14 package has separate power and ground pins for the totem pole output stage. The UC2843AN has UYLO thresholds of 16 V (on) and 10 V (off), ideally suited for off–line converters. It is tailored for lower voltage applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off).

Parametrics

UC2843AN absolute maximum ratings: (1)Bias and Driver Voltages (Zero Series Impedance, see also Total Device spec) VCC, VC: 30 V; (2)Total Power Supply and Zener Current (ICC + IZ): 30 mA; (3)Output Current, Source or Sink IO: 1.0 A; (4)Output Energy (Capacitive Load per Cycle) W: 5.0 μJ; (5)Current Sense and Voltage Feedback Inputs Vin: 0.3 to + 5.5 V; (6)Error Amp Output Sink Current IO: 10 mA; (7)Power Dissipation and Thermal Characteristics N Suffix, Plastic Package: Maximum Power Dissipation @ TA = 25℃ PD 1.25W, Thermal Resistance, Junction–to–Air RθJA 100 ℃/W; (8)Operating Junction Temperature TJ: + 150 ℃; (9)Operating Ambient Temperature TA: – 25 to + 85℃; (10)Storage Temperature Range Tstg: – 65 to + 150 ℃.

Features

UC2843AN features: (1)Trimmed Oscillator Discharge Current for Precise Duty Cycle Control; (2)Current Mode Operation to 500 kHz; (3)Automatic Feed Forward Compensation; (4)Latching PWM for Cycle-by-Cycle Current Limiting; (5)Internally Trimmed Reference with Undervoltage Lockout; (6)High Current Totem Pole Output; (7)Undervoltage Lockout with Hysteresis; (8)Low Startup and Operating Current; (9)Direct Interface with ON Semiconductor SENSEFET Products.

Diagrams