TL494, NCV494 SWITCHMODE Pulse Width Modulation Control Circuit The TL494 is a fixed frequency, pulse width modulation control circuit designed primarily for SWITCHMODE power supply control. Features TL494, NCV494 RECOMMENDED OPERATING CONDITIONS Characteristics Symbol Min Typ Max Unit Power Supply Voltage V 7.0 15 40 V CC Collector Output Voltage V , V 30 40 V C1 C2 Collector Output Current (Each transistor) I , I 200 mA C1 C2 Amplified Input Voltage V 0.3 V 2.0 V in CC Current Into Feedback Terminal l 0.3 mA fb Reference Output Current l 10 mA ref Timing Resistor R 1.8 30 500 k T Timing Capacitor C 0.0047 0.001 10 F T Oscillator Frequency f 1.0 40 200 kHz osc ELECTRICAL CHARACTERISTICS (V = 15 V, C = 0.01 F, R = 12 k , unless otherwise noted.) CC T T For typical values T = 25C, for min/max values T is the operating ambient temperature range that applies, unless otherwise noted. A A Characteristics Symbol Min Typ Max Unit REFERENCE SECTION Reference Voltage (I = 1.0 mA) V 4.75 5.0 5.25 V O ref Line Regulation (V = 7.0 V to 40 V) Reg 2.0 25 mV CC line Load Regulation (I = 1.0 mA to 10 mA) Reg 3.0 15 mV O load Short Circuit Output Current (V = 0 V) I 15 35 75 mA ref SC OUTPUT SECTION Collector OffState Current I 2.0 100 A C(off) (V = 40 V, V = 40 V) CC CE Emitter OffState Current I 100 A E(off) V = 40 V, V = 40 V, V = 0 V) CC C E CollectorEmitter Saturation Voltage (Note 2) V CommonEmitter (V = 0 V, I = 200 mA) V 1.1 1.3 E C sat(C) EmitterFollower (V = 15 V, I = 200 mA) V 1.5 2.5 C E sat(E) Output Control Pin Current Low State (V 0.4 V) I 10 A OC OCL High State (V = V ) I 0.2 3.5 mA OC ref OCH Output Voltage Rise Time t ns r CommonEmitter (See Figure 12) 100 200 EmitterFollower (See Figure 13) 100 200 Output Voltage Fall Time t ns f CommonEmitter (See Figure 12) 25 100 EmitterFollower (See Figure 13) 40 100 2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible.