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DS20005208B-page 7

MCP1643

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

MSOP-8 package.

FIGURE 2-13:

Start-up After Enable.

FIGURE 2-14:

100 mA PWM Operation.

FIGURE 2-15:

400 Hz PWM Dimming,

85% Duty Cycle.

FIGURE 2-16:

Start-up when VIN =VEN.

FIGURE 2-17:

400 Hz PWM Dimming,

15% Duty Cycle.

FIGURE 2-18:

Open Load Response.

VEN

80 us/div

1V/div

VIN

ILED

20 mA/div

1V/div

20 mV/div, AC Coupled

VOUT

1V/div

VSW

ILED

100 mA/div

1us/div

ILED

50 mA/div

1V/div

VSW

1V/div

VEN

400 us/div

80 us/div

500 mA/div

IL

1V/div

VIN

ILED

20 mA/div

ILED

50 mA/div

1V/div

VSW

1V/div

VEN

400 us/div

10 ms/div

2V/div

100 mA/div

VOUT

ILED

ILED Step from 100 mA to Open Load

VOUT Step from 2V to 5V

VSW

2V/div