UC1824 UC2824 UC3824 UDG-92034-1 DIL-16 PLCC-20 LCC-20 SOIC-16 UDG-92036-2

UC2824 UC3824 High Speed PWM Controller FEATURES DESCRIPTION · Complementary Outputs · Practical Operation

UC1824 UC1824 UC2824 UC2824 UC3824 UC3824 High Speed PWM Controller FEATURES DESCRIPTION · Complementary Outputs · Practical Operation Switching Frequencies to 1MHz · 50ns Propagation Delay to Output · High Current Dual Totem Pole Outputs (1.5A Peak) The UC1824 UC1824 family of PWM control ICs is optimized for high frequency switched mode power supply applications. Particular care was given to minimizing propagation delays through the comparators and logic circuitry while maximizing bandwidth and slew rate of the error amplifier. This controller is designed for use in either currentmode or voltage mode systems with the capability for input voltage feed-forward. · Wide Bandwidth Error Amplifier · Fully Latched Logic with Double Pulse Suppression · Pulse-by-Pulse Current Limiting · Soft Start / Max. Duty Cycle Control · Under-Voltage Lockout with Hysteresis · Low Start Up Current (1.1 mA) · Trimmed Bandgap Reference (5.1V ± 1%) Protection circuitry includes a current limit comparator with a 1V threshold, a TTL compatible shutdown port, and a soft start pin which will double as a maximum duty cycle clamp. The logic is fully latched to provide jitter free operation and prohibit multiple pulses at an output. An under-voltage lockout section with 800mV of hysteresis assures low start up current. During under-voltage lockout, the outputs are high impedance. These devices feature totem pole outputs designed to source and sink high peak currents from capacitive loads, such as the gate of a power MOSFET. The on state is designed as a high level. BLOCK DIAGRAM UDG-92034-1 UDG-92034-1 3/97 ABSOLUTE MAXIMUM RATINGS (Note 1) UC1824 UC1824 UC2824 UC2824 UC3824 UC3824 CONNECTION DIAGRAMS Supply Voltage (Pins 13, 15) . . . . . . . . . . . . . . . . . . . . . . . . 30V Output Current, Source or Sink (Pins 11, 14) DC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5A Pulse (0.5µs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0A Analog Inputs (Pins 1, 2, 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V (Pin 8, 9) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6V Clock Output Current (Pin 4) . . . . . . . . . . . . . . . . . . . . . . . -5mA Error Amplifier Output Current (Pin 3) . . . . . . . . . . . . . . . . 5mA Soft Start Sink Current (Pin 8) . . . . . . . . . . . . . . . . . . . . . 20mA Oscillator Charging Current (Pin 5) . . . . . . . . . . . . . . . . . . -5mA Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1W Storage Temperature Range . . . . . . . . . . . . . . -65°C to +150°C Lead Temperature (Soldering, 10 seconds) . . . . . . . . . . 300°C Note 1: All voltages are with respect to GND (Pin 10); all currents are positive into, negative out of part; pin numbers refer to DIL-16 DIL-16 package. Note 3: Consult Unitrode Integrated Circuit Databook for thermal limitations and considerations of package. DIL-16 DIL-16 (Top View) J Or N Package PACKAGE PIN FUNCTION PLCC-20 PLCC-20 & LCC-20 LCC-20 (Top View) Q & L Packages SOIC-16 SOIC-16 (Top View) DW Package FUNCTION N/C INV NI E/A Out Clock N/C RT CT Ramp Soft Start N/C ILIM/SD Gnd Out Pwr Gnd N/C VC INVOUT VCC VREF 5.1V PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ELECTRICAL CHARACTERISTICS: Unless otherwise stated,these specifications apply for , RT = 3.65k, CT = 1nF, VCC = 15V, -55°C