LT1765/LT1765-1.8/LT1765-2.5/

LT1765-3.3/LT1765-5

3

1765fd

ELECTRICAL CHARACTERISTICS

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 LT1765E is guaranteed to meet performance specifications

from 0°C to 125°C. Specifications over the –40°C to 125°C operating

junction temperature range are assured by design, characterization and

correlation with statistical process controls.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Maximum Switch Current Limit

346

A

Oscillator Frequency

l

1.1

1.25

1.6

MHz

Switch On Voltage Drop

I = 3A

l

270

430

mV

(Note 3)

l

2.47

2.6

2.73

V

l

1

1.3

mA

Shutdown Supply Current

l

15

35

55

μA

μA

Feedback Voltage

(Note 3)

LT1765 (Adj)

l

1.182

1.176

1.2

1.218

1.224

V

V

LT1765-1.8

l

1.764

1.8

1.836

V

LT1765-2.5

l

2.45

2.5

2.55

V

LT1765-3.3

l

3.234

3.3

3.366

V

LT1765-5

l

4.9

5

5.1

V

FB Input Current

LT1765 (Adj)

l

–0.25

–0.5

μA

FB Input Resistance

LT1765-1.8

LT1765-2.5

LT1765-3.3

LT1765-5

l

l

l

l

10.5

14.7

19

29

15

21

27.5

42

21

30

39

60

kΩ

kΩ

kΩ

kΩ

FB Error Amp Voltage Gain

150

350

FB Error Amp Transconductance

l

500

850

1300

μMho

l

80

120

160

μA

l

70

110

180

μA

5A/V

Duty Cycle = 0%

0.4

V

0.9

V

Maximum Switch Duty Cycle

l

85

80

90

%

%

Minimum Boost Voltage Above Switch

l

1.8

2.7

V

Boost Current

l

l

20

70

30

140

mA

mA

SHDN Threshold Voltage

l

1.27

1.33

1.40

V

SHDN Threshold Current Hysteresis

l

47

10

μA

SHDN Input Current (Shutting Down)

SHDN = 60mV Above Threshold

l

–7

–10

–13

μA

SYNC Threshold Voltage

1.5

2.2

V

SYNC Input Frequency

1.6

2

MHz

SYNC Pin Resistance

20

kΩ

The

Note 3: Minimum input voltage is defined as the voltage where the internal

regulator enters lockout. Actual minimum input voltage to maintain a

regulated output will depend on output voltage and load current. See

Applications Information.

Note 4: Current flows into the BOOST pin only during the on period of the

switch cycle.