4 Output Pin 2 sourcing current No diode inductor or capacitor connected to

4 output pin 2 sourcing current no diode inductor or

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4. Output (Pin 2) sourcing current. No diode, inductor or capacitor connected to output pin. 5. Feedback (Pin 4) removed from output and connected to 0 V. 6. Feedback (Pin 4) removed from output and connected to +12 V for the Adjustable, 3.3 V, and 5.0 V versions, and +25 V for the 12 V and 15 V versions, to force the output transistor “off”. 7. V in = 40 V.
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LM2576 5 I Q , QUIESCENT CURRENT (mA) 40 TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 15) V out , OUTPUT VOLTAGE CHANGE (%) V out , OUTPUT VOLTAGE CHANGE (%) , STANDBY QUIESCENT CURRENT ( T J , JUNCTION TEMPERATURE ( ° C) I O , OUTPUT CURRENT (A) T J , JUNCTION TEMPERATURE ( ° C) V in , INPUT VOLTAGE (V) V in , INPUT VOLTAGE (V) INPUT − OUTPUT DIFFERENTIAL (V) T J , JUNCTION TEMPERATURE ( ° C) Figure 2. Normalized Output Voltage T J , JUNCTION TEMPERATURE ( ° C) Figure 3. Line Regulation Figure 4. Dropout Voltage Figure 5. Current Limit Figure 6. Quiescent Current Figure 7. Standby Quiescent Current I Load = 200 mA I Load = 3.0 A V in = 12 V V in = 40 V L1 = 150 mH R ind = 0.1 W I Load = 500 mA I Load = 3.0 A V out = 5.0 V Measured at Ground Pin T J = 25 ° C V ON/OFF = 5.0 V μ A) 1.0 0.6 0.2 0 −0.2 −0.4 −1.0 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 −0.2 −0.4 −0.6 2.0 1.5 1.0 0.5 0 6.5 6.0 5.5 5.0 4.5 4.0 20 18 16 14 12 10 8.0 6.0 4.0 200 180 160 140 120 100 80 60 20 0 125 100 75 50 25 0 −25 −50 40 35 30 25 20 15 10 5.0 0 125 100 75 50 25 0 −25 −50 125 100 75 50 25 0 −25 −50 40 35 30 25 20 15 10 5.0 0 125 100 75 50 25 0 −25 −50 −0.8 −0.6 0.4 0.8 V in = 20 V I Load = 500 mA Normalized at T J = 25 ° C I Load = 500 mA T J = 25 ° C 3.3 V, 5.0 V and ADJ 12 V and 15 V V in = 25 V I stby
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LM2576 6 V sat , SATURATION VOLTAGE (V) 2.0 2.5 3.0 4.0 I b , FEEDBACK PIN CURRENT (nA) , STANDBY QUIESCENT CURRENT ( μ A) I stby , INPUT VOLTAGE (V) T J , JUNCTION TEMPERATURE ( ° C) SWITCH CURRENT (A) NORMALIZED FREQUENCY (%) T J , JUNCTION TEMPERATURE ( ° C) Figure 8. Standby Quiescent Current V in , INPUT VOLTAGE (V) Figure 9. Switch Saturation Voltage Figure 10. Oscillator Frequency Figure 11. Minimum Operating Voltage Figure 12. Feedback Pin Current V in = 12 V Normalized at 25 ° C T J = 25 ° C Adjustable Version Only 200 180 140 120 100 80 60 40 20 0 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 8.0 6.0 4.0 2.0 0 −2.0 −4.0 −6.0 −8.0 −10 5.0 4.5 3.5 1.5 1.0 0.5 0 40 30 25 20 15 10 5 0 0 0.5 1.0 1.5 2.0 3.0 125 100 75 50 25 0 −25 −50 125 100 75 50 25 0 −25 −50 T J , JUNCTION TEMPERATURE ( ° C) Adjustable Version Only 100 80 60 40 20 0 −20 −40 −60 −80 −100 125 100 75 50 25 0 −25 −50 160 35 2.5 −40 ° C 25 ° C 125 ° C V out ' 1.23 V I Load = 500 mA TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 15) V in
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LM2576 7 2.0 A 0 0 A B C 100 ms/DIV 5 ms/DIV Figure 13. Switching Waveforms Figure 14. Load Transient Response Vout = 15 V A: Output Pin Voltage, 10 V/DIV B: Inductor Current, 2.0 A/DIV C: Inductor Current, 2.0 A/DIV, AC−Coupled D: Output Ripple Voltage, 50 mV/dDIV, AC−Coupled Horizontal Time Base: 5.0 m s/DIV 50 V 0 4.0 A 2.0 A 100 mV Output Voltage Change 0 3.0 A 2.0 A 1.0 A 0 4.0 A − 100 mV Load Current TYPICAL PERFORMANCE CHARACTERISTICS (Circuit of Figure 15) D
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LM2576 8 Figure 15. Typical Test Circuit D1 MBR360 L1 100 mH Output 2 4 Feedback C out 1000 mF C in 100 mF LM2576 Fixed Output 1 5 3 ON/OFF GN D V in Load V out D1 MBR360 L1 100 mH Output 2 4 Feedback C out 1000 mF C in 100 mF LM2576 Adjustable 1 5 3 ON/OFF GN D V in Load V out 5,000 V Fixed Output Voltage Versions Adjustable Output Voltage Versions V out + V ref ǒ 1.0 ) R2 R1 Ǔ R2 + R1 ǒ V out V ref –1.0 Ǔ Where V ref = 1.23 V, R1 between 1.0 k and 5.0 k R2 R1 C in 100 m F, 75 V, Aluminium Electrolytic C out 1000 m
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  • Spring '19
  • Margaret Earle
  • Switched-mode power supply, Vout

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