LT1945

3

1945fa

Note 1: Stresses beyond those listed under Absolute Maximum Ratings may

cause permanent damage to the device. Exposure to any Absolute Maximum

Rating condition for extended periods may affect device reliability and lifetime.

Note 2: The LT1945E is guaranteed to meet performance specifications

from 0°C to 70°C junction temperature. Specifications over the –40°C

to 85°C operating junction temperature range are assured by design,

characterization and correlation with statistical process controls. The

LT1945I is guaranteed over the full –40°C to 125°C operating junction

temperature range.

Note 3: Bias current flows out of the NFB1 pin.

Note 4: Bias current flows into the FB2 pin.

Note 5: See Figure 1 for Switcher 1 and Switcher 2 locations.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

SHDN Pin Current

2

8

3

12

μA

μA

SHDN Input Voltage High

0.9

V

SHDN Input Voltage Low

0.25

V

Switch Leakage Current

0.01

5

μA

TYPICAL PERFORMANCE CHARACTERISTICS

TEMPERATURE (°C)

–50

–25

0

25

50

75

100

1945 G01

0.60

0.55

0.50

0.45

0.40

0.35

0.30

0.25

0.20

0.15

0.10

TEMPERATURE (°C)

–50

1945 G02

1.25

1.24

1.23

1.22

1.21

1.20

50

40

30

20

10

0

CURRENT

VOLTAGE

–25

0

25

50

75

100

TEMPERATURE (°C)

1945 G03

–1.25

–1.24

–1.23

–1.22

–1.21

–1.20

–50

–25

0

0

1

2

3

4

5

25

50

75

100

VOLTAGE

CURRENT

TEMPERATURE (°C)

1945 G04

550

500

450

400

350

300

250

–50

–25

0

25

50

75

100

TEMPERATURE (°C)

1945 G05

400

350

300

250

200

150

100

50

0

–50

–25

0

25

50

75

100

TEMPERATURE (°C)

1945 G06

25

23

21

19

17

15

–50

–25

0

25

50

75

100

NOT SWITCHING

Switch Off Time

Switch Current Limit

Quiescent Current

Switch Saturation Voltage

(VCESAT)

FB2 Pin Voltage and

Bias Current

NFB1 Pin Voltage and

Bias Current