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Typical Characteristics

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

913

17

21

25

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

9

12

1518212427

30333639

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

16

19

22

25

28

31

34

37

40

PT78ST133, 3.3 VDC

(See Note 1)

PT78ST112, 12.0 VDC

(See Note 1)

Efficiency vs Output Current

Ripple vs Output Current

(See Note 2)

Power Dissipation vs Output Current

Iout-(Amps)

Iout-(Amps)

Iout-(Amps)

Iout-(Amps)

Iout-(Amps)

Iout-(Amps)

Iout-(Amps)

Iout-(Amps)

Iout-(Amps)

Vin-(Volts)

Vin-(Volts)

Vin-(Volts)

40

50

60

70

80

90

100

0

0.25

0.5

0.75

1

1.25

1.5

9.0V

12.0V

15.0V

20.0V

26.0V

Vin

40

50

60

70

80

90

100

0

0.25

0.5

0.75

1

1.25

1.5

16.0V

18.0V

24.0V

30.0V

38.0V

Vin

0

50

100

150

200

250

300

0

0.25

0.5

0.75

1

1.25

1.5

38.0V

30.0V

24.0V

18.0V

16.0V

Vin

0

20

40

60

80

100

00.25

0.5

0.7511.25

1.5

26.0V

20.0V

15.0V

12.0V

9.0V

Vin

0

0.5

1

1.5

2

2.5

3

0

0.25

0.5

0.75

1

1.25

1.5

38.0V

30.0V

24.0V

18.0V

16.0V

Vin

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

00.25

0.5

0.7511.25

1.5

26.0V

20.0V

15.0V

12.0V

9.0V

Vin

85°C

60°C

70°C

85°C

85°C

70°C

Note 1:

All data listed in the above graphs, except for derating data, has been developed from actual products tested at 25°C. This data is considered typical data for the ISR.

Note 2:

Thermal derating graphs are developed in free air convection cooling of 40-60 LFM. (See Thermal Application Notes.)

40

50

60

70

80

90

100

0

0.25

0.5

0.75

1

1.25

1.5

9.0V

12.0V

18.0V

24.0V

30.0V

38.0V

Vin

0

30

60

90

120

150

0

0.25

0.5

0.75

1

1.25

1.5

38.0V

30.0V

24.0V

18.0V

12.0V

9.0V

Vin

0

0.5

1

1.5

2

2.5

0

0.25

0.5

0.75

1

1.25

1.5

38.0V

30.0V

24.0V

18.0V

12.0V

9.0V

Vin

60°C

70°C

60°C

Efficiency vs Output Current

Efficiency vs Output Current

Ripple vs Output Current

Ripple vs Output Current

(See Note 2)

(See Note 2)

Power Dissipation vs Output Current

Power Dissipation vs Output Current

1.5 Amp Positive Step-Down

Integrated Switching Regulator

PT78ST100 Series