UC3844B, UC3845B, UC2844B, UC2845B High Performance Current Mode Controllers The UC3844B, UC3845B series are high performance fixed frequency current mode controllers. They are specifically designed for OffLine and dcdc converter applications offering the designer a costeffective solution with minimal external components. These integrated circuits UC3844B, UC3845B, UC2844B, UC2845B MAXIMUM RATINGS Rating Symbol Value Unit Bias and Driver Voltages (Zero Series Impedance, see also Total Device spec) (Note 1) V , V 36 V CC C Total Power Supply and Zener Current (I + I ) 30 mA CC Z Output Current, Source or Sink (Note 2) I 1.0 A O Output Energy (Capacitive Load per Cycle) W 5.0 J Current Sense and Voltage Feedback Inputs V 0.3 to + 5.5 V in Error Amp Output Sink Current I 10 mA O Power Dissipation and Thermal Characteristics D Suffix, Plastic Package, SOIC14 Case 751A Maximum Power Dissipation T = 25C P 862 mW A D Thermal Resistance, JunctiontoAir R 145 C/W JA D1 Suffix, Plastic Package, SOIC8 Case 751 Maximum Power Dissipation T = 25C P 702 mW A D Thermal Resistance, JunctiontoAir 178 C/W R JA N Suffix, Plastic Package, Case 626 Maximum Power Dissipation T = 25C P 1.25 W A D Thermal Resistance, JunctiontoAir R 100 C/W JA Operating Junction Temperature T +150 C J Operating Ambient Temperature UC3844B, UC3845B T 0 to +70 C A UC2844B, UC2845B 25 to +85 UC3844BV, UC3845BV 40 to +105 Storage Temperature Range T 65 to +150 C stg Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. 1. The voltage is clamped by a zener diode (see page 9 Under Voltage Lockout section). Therefore this voltage may be exceeded as long as the total power supply and zener current is not exceeded. 2. Maximum package power dissipation limits must be observed. 3. This device series contains ESD protection and exceeds the following tests: Human Body Model 4000 V per JEDEC Standard JESD22-A114B, Machine Model Method 200 V per JEDEC Standard JESD22-A115-A 4. This device contains latch-up protection and exceeds 100 mA per JEDEC Standard JESD78 ELECTRICAL CHARACTERISTICS (V = 15 V Note 5 , R = 10 k, C = 3.3 nF. For typical values T = 25C, for min/max values CC T T A T is the operating ambient temperature range that applies Note 6 , unless otherwise noted.) A UC284xB UC384xB, xBV, NCV384xBV Characteristic Symbol Min Typ Max Min Typ Max Unit REFERENCE SECTION Reference Output Voltage (I = 1.0 mA, T = 25C) V 4.95 5.0 5.05 4.9 5.0 5.1 V O J ref Line Regulation (V = 12 V to 25 V) Reg 2.0 20 2.0 20 mV CC line Load Regulation (I = 1.0 mA to 20 mA) Reg 3.0 25 3.0 25 mV O load Temperature Stability T 0.2 0.2 mV/C S Total Output Variation over Line, Load, & Temperature V 4.9 5.1 4.82 5.18 V ref Output Noise Voltage (f = 10 Hz to 10 kHz, T = 25C) V 50 50 V J n Long Term Stability (T = 125C for 1000 Hours) S 5.0 5.0 mV A Output Short Circuit Current I 30 85 180 30 85 180 mA SC OSCILLATOR SECTION Frequency T = 25C f 49 52 55 49 52 55 kHz J OSC T = T to T 48 56 48 56 A low high T = 25C (R = 6.2 k, C = 1.0 nF) 225 250 275 225 250 275 J T T Frequency Change with Voltage (V = 12 V to 25 V) f / V 0.2 1.0 0.2 1.0 % CC OSC Frequency Change w/ Temperature (T = T to T ) f / T 1.0 0.5 % A low high OSC Oscillator Voltage Swing (PeaktoPeak) V 1.6 1.6 V OSC 5. Adjust V above the Startup threshold before setting to 15 V. CC 6. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible. T =0C for UC3844B, UC3845B T =+70C for UC3844B, UC3845B low high = 25C for UC2844B, UC2845B = + 85C for UC2844B, UC2845B = 40C for UC384xBV, NCV384xBV =+105C for UC3844BV, UC3845BV = +125C for NCV384xBV