SG2525A SG3525A REGULATING PULSE WIDTH MODULATORS . 8 TO 35 V OPERATION . 5.1 V REFERENCE TRIMMED TO 1 % . 100 Hz TO 500 KHz OSCILLATOR RANGE . SEPARATE OSCILLATOR SYNC TERMINAL . ADJUSTABLE DEADTIME CONTROL . INTERNAL SOFT-START . PULSE-BY-PULSE SHUTDOWN .INPUT UNDERVOLTAGE LOCKOUT WITH DIP16 16(Narrow) HYSTERESIS .LATCHING PWM TO PREVENT MULTIPLE PULSES . DUAL SOURCE/SINK OUTPUT DRIVERS DESCRIPTION The SG3525A series of pulse width modulator inte- turn off through the PWM latch with pulsed shut- grated circuits are designed to offer improved per- down, as well as soft-start recycle with longer shut- formance and lowered external parts count when down commands. These functions are also control- used in designing all types of switching power sup- led by an undervoltage lockout which keeps the out- plies. The on-chip + 5.1 V reference is trimmed to puts off and the soft-start capacitor discharged for 1 % and the input common-mode range of the error sub-normal input voltages. This lockout circuitry in- amplifier includes the reference voltage eliminating cludes approximately 500 mV of hysteresis for jitter- external resistors. A sync input to the oscillator al- free operation. Another feature of these PWM cir- lows multiple units to be slaved or a single unit to be cuits is a latch following the comparator. Once a synchronized to an external system clock. A single PWM pulses has been terminated for any reason, resistor between the C and the discharge terminals T the outputs will remain off for the duration of the pe- provide a wide range of dead time ad- justment. riod. The latch is reset with each clock pulse. The These devices also feature built-in soft-start circuitry output stages are totem-pole designs capable of with only an external timing capacitor required. A sourcing or sinking in excess of 200 mA. The shutdown terminal controls both the soft-start circu- SG3525A output stage features NOR logic, giving a ity and the output stages, providing instantaneous LOW output for an OFF state. PIN CONNECTIONS AND ORDERING NUMBERS (top view) Type Plastic DIP SO16 SG2525A SG2525AN SG2525AP SG3525A SG3525AN SG3525AP June 2000 1/12SG2525A-SG3525A ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit V Supply Voltage 40 V i V Collector Supply Voltage 40 V C I Oscillator Charging Current 5 mA OSC I Output Current, Source or Sink 500 mA o I Reference Output Current 50 mA R I Current through C Terminal 5 mA T T Logic Inputs 0.3 to + 5.5 V Analog Inputs 0.3 to V V i P Total Power Dissipation at T = 70 C 1000 mW tot amb T Junction Temperature Range 55 to 150 C j T Storage Temperature Range 65 to 150 C stg T Operating Ambient Temperature : SG2525A 25 to 85 C op SG3525A 0 to 70 C THERMAL DATA Symbol Parameter SO16 DIP16 Unit R Thermal Resistance Junction-pins Max 50 C/W th j-pins R Thermal Resistance Junction-ambient Max 80 C/W th j-amb Rth j-alumina Thermal Resistance Junction-alumina (*) Max 50 C/W * Thermal resistance junction-alumina with the device soldered on the middle of an alumina supporting substrate measuring 15 20 mm 0.65 mm thickness with infinite heatsink. BLOCK DIAGRAM 2/12