4

LT1572

ELECTRICAL C

C

temperature range, 0

°C to 100°C for the regulator chip and 0°C to 125°C

for the diode.

Note 2: For duty cycles (DC) between 50% and 80%, minimum

Note 3: Minimum input voltage for isolated flyback mode is 7V.

Note 4: Because the catch diode has a peak repetitive reverse voltage of

20V, diode breakdown may be the limiting factor on input voltage or

switch voltage in many applications.

Note 5: See graphs for guaranteed forward voltage and reverse leakage

current over temperature. Parameters are 100% tested at 25

°C and

guaranteed at other temperatures by design and QA sampling.

Note 6: Package soldered to FR4 board with

≥1oz copper and an internal

or backside plane underneath the package to aid thermal transfer. Diode is

partly thermally coupled to regulator section. See Application Information

section for details on thermal calculations.

CC

HARA TERISTICS

A

TYPICALPERFOR

CE

Reference Voltage vs Temperature

Feedback Bias Current vs

Temperature

Minimum Input Voltage

Switch Saturation Voltage

Switch Current Limit vs Duty Cycle

Line Regulation

DUTY CYCLE (%)

0

4

3

2

1

0

40

1572 G01

20 30

50 60 70 80 90 100

25

°C

125

°C

–55

°C

10

TEMPERATURE (

°C)

–75

–25

25

50

150

1572 G02

–50

0

75 100 125

2.9

2.8

2.7

2.6

2.5

2.4

2.3

SWITCH CURRENT = 0A

SWITCH CURRENT = 1.25A

SWITCH CURRENT (A)

0

2.00

1572 G03

0.25 0.50 0.75

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

1.00 1.25 1.50 1.75

25

°C

150

°C

–55

°C

100

°C

INPUT VOLTAGE (V)

0

10

20

30

40

1572 G04

50

5

4

3

2

1

0

–1

–2

–3

–4

–5

60

TEMPERATURE (

°C)

1572 G05

1.250

1.248

1.246

1.244

1.242

1.240

1.238

1.236

1.234

–75

–25

25

50

150

–50

0

75 100 125

TEMPERATURE (

°C)

1572 G06

800

700

600

500

400

300

200

100

0

–75

–25

25

50

150

–50

0

75 100 125