MCP1643

DS20005208B-page 6

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Note: Unless otherwise indicated, VIN = EN = 1.2V, COUT =20µF, CIN =10µF, L = 4.7µH, ILED =25mA, TA = +25°C,

MSOP-8 package.

FIGURE 2-7:

One White ILED vs. Ambient

Temperature.

FIGURE 2-8:

ILED vs. VEN Duty Cycle.

FIGURE 2-9:

Duty Cycle vs. Ambient

Temperature.

FIGURE 2-10:

Maximum ILED vs. VIN.

FIGURE 2-11:

fSW vs. Ambient

Temperature.

FIGURE 2-12:

VFB vs. Ambient

Temperature.

0

50

100

150

200

250

300

350

-40

-25

-10

5

20

35

50

65

80

Ambient Temperature (°C)

R

SET = 5

R

SET = 1.2

R

SET = 0.82

R

SET = 0.41

V

IN = 1.5V

0

25

50

75

100

125

150

0

10

20

30

40

50

60

70

80

90 100

Duty Cycle (%)

R

SET = 0.82

V

IN = 1.5V

f

EN = 400 Hz

f

EN = 1 kHz

34

35

36

37

38

39

40

-40

-25

-10

5

20

35

50

65

80

Ambient Temperature (°C)

R

SET = 1.2

(I

LED = 100 mA)

0

100

200

300

400

500

600

700

0.6

0.9

1.2

1.5

1.8

2.1

2.4

2.7

3

Input Voltage (V)

T

A = +85

oC

T

A = +25

oC

T

A = 0

oC

980

985

990

995

1000

1005

1010

-40

-25

-10

5

20

35

50

65

80

Ambient Temperature (°C)

I

LED = 100 mA

117

118

119

120

121

122

123

-40

-25

-10

5

20

35

50

65

80

Ambient Temperature (°C)

I

LED = 100 mA