PT78ST100_07 Datasheet, PDF (2/7 Pages) Texas Instruments – 1.5 Amp Positive Step-Down Integrated Switching Regulator

PT78ST100 Series
1.5 Amp Positive Step-Down
Integrated Switching Regulator
Typical Characteristics
PT78ST133, 3.3 VDC (See Note 1)
PT78ST105, 5.0 VDC (See Note 1)
PT78ST112, 12.0 VDC (See Note 1)
Efficiency vs Output Current
100
90
80
70
60
50
40
0
Vin
9.0V
12.0V
15.0V
20.0V
26.0V
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
Ripple vs Output Current
100
80
Vin
26.0V
60
20.0V
15.0V
12.0V
40
9.0V
20
0
0
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
Thermal Derating (T_a) (See Note 2)
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
9
85°C
60°C
70°C
13
17
21
25
Vin-(Volts)
Power Dissipation vs Output Current
1.8
1.6
1.4
Vin
1.2
26.0V
1
20.0V
15.0V
0.8
12.0V
0.6
9.0V
0.4
0.2
0
0
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
Efficiency vs Output Current
100
90
Vin
80
9.0V
12.0V
18.0V
70
24.0V
30.0V
60
38.0V
50
40
0
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
Ripple vs Output Current
150
120
Vin
90
38.0V
30.0V
24.0V
18.0V
60
12.0V
9.0V
30
0
0
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
Thermal Derating (T_a) (See Note 2)
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
9
60°C
70°C
85°C
12 15 18 21 24 27 30 33 36 39
Vin-(Volts)
Power Dissipation vs Output Current
2.5
2
Vin
1.5
38.0V
30.0V
24.0V
18.0V
1
12.0V
9.0V
0.5
0
0
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
Efficiency vs Output Current
100
90
80
Vin
16.0V
18.0V
70
24.0V
30.0V
60
38.0V
50
40
0
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
Ripple vs Output Current
300
250
200
Vin
38.0V
150
30.0V
24.0V
18.0V
100
16.0V
50
0
0
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
Thermal Derating (T_a) (See Note 2)
1.6
1.4
1.2
70°C
60°C
1
85°C
0.8
0.6
0.4
0.2
0
16
19
22
25
28
31
34
37
40
Vin-(Volts)
Power Dissipation vs Output Current
3
2.5
2
1.5
Vin
38.0V
1
30.0V
24.0V
0.5
18.0V
16.0V
0
0
0.25
0.5
0.75
1
1.25
1.5
Iout-(Amps)
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.)
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