3

LTC1643L/LTC1643L-1/LTC1643H

3.3V and 5V Current

Foldback Profile

OUTPUT VOLTAGE (V)

0

11

10

9

8

7

6

5

4

3

2

1

0

4

1643 G01

1

2

3

5

OUTPUT VOLTAGE (V)

0

1.0

0.5

0

–8

–10

1643 G03

–2

–4

–6

–12

OUTPUT VOLTAGE (V)

0

1.0

0.5

0

810

1643 G02

2

4

6

12

12V Current Foldback Profile

– 12V Current Foldback Profile

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Power-Good Threshold Voltage

C Grade

q

2.8

2.9

3.0

V

I Grade

q

2.75

2.9

3.0

V

C Grade

q

4.5

4.65

4.75

V

I Grade

q

4.4

4.65

4.75

V

Input Low Voltage

ON/ON, FAULT

q

0.8

V

Input High Voltage

ON/ON, FAULT

q

2V

Output Low Voltage

FAULT, PWRGD, I = 3mA

q

0.4

V

ON/ON Pin Input Current

ON/ON = GND

q

± 0.08

±10

µA

q

± 0.08

±10

µA

q

50

100

µA

q

50

100

µA

q

460

700

µA

q

320

600

µA

q

240

500

µA

q

220

500

µA

ON = GND or ON = 3V

100

Ω

ON = GND or ON = 3V

70

Ω

ON = GND or ON = 3V

450

Ω

ON = GND or ON = 3V

1600

Ω

TIMER Pin Current

q

–15

– 22

– 27

µA

45

mA

TIMER Threshold Voltage

q

0.5

0.9

1.3

V

Note 2: All currents into device pins are positive; all currents out of device

pins are negative. All voltages are referenced to ground unless otherwise

specified.

Note 1: Absolute Maximum Ratings are those values beyond which the life

of a device may be impaired.