3

LT1512

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Output Switch ON Resistance

q

0.5

0.8

Ω

Switch Current Limit

Duty Cycle = 50%

q

1.5

1.9

2.7

A

Duty Cycle = 80% (Note 1)

q

1.3

1.7

2.5

A

Supply Current Increase During Switch ON Time

15

25

mA/A

Control Voltage to Switch Current

2A/V

Transconductance

Minimum Input Voltage

q

2.4

2.7

V

Supply Current

2.7V

q

4

5.5

mA

Shutdown Supply Current

2.7V

0

q

12

30

µA

–40

50

µA

Shutdown Threshold

2.7V

q

0.6

1.3

2

V

Shutdown Delay

q

512

25

µs

S/S Pin Input Current

0V

q

–10

15

µA

Synchronization Frequency Range

q

600

800

kHz

ELECTRICAL C

C

HARA TERISTICS

temperature range.

Note 1: For duty cycles (DC) between 50% and 85%, minimum

Note 3: Commercial devices are guaranteed over 0

°C to 125°C junction

temperature range and 0

°C to 70°C ambient temperature range. These

parts are also designed, characterized and expected to operate over the

–20

°C to 85°C extended ambient temperature range, but are not tested at

–20

°C or 85°C. Devices with full guaranteed electrical specifications over

the ambient temperature range – 40

°C to 85°C are available as industrial

parts with an “I” suffix.

Maximum allowable ambient temperature may be limited by power

dissipation. Parts may not necessarily be operated simultaneously at

maximum power dissipation and maximum ambient temperature.

Temperature rise calculations must be done as shown in the Applications

Information section to ensure that maximum junction temperature does

not exceed 125

°C limit. With high power dissipation, maximum ambient

temperature may be less than 70

°C.

Switch Saturation Voltage

vs Switch Current

Minimum Input Voltage

vs Temperature

Switch Current Limit

vs Duty Cycle

SWITCH CURRENT (A)

0

0.6

0.8

1.0

1.6

1512 G01

0.4

0.2

0.5

0.7

0.9

0.3

0.1

0

0.4

0.8

1.2

2.0

1.4

0.2

0.6

1.0

1.8

100

°C

150

°C

25

°C

–55

°C

DUTY CYCLE (%)

3.0

2.5

2.0

1.5

1.0

0.5

0

20

40

60

80

1512 G02

100

10

0

30

50

70

90

25

°C AND

125

°C

–55

°C

TEMPERATURE (

°C)

–50

1.8

2.0

2.2

2.4

2.6

050

100

150

1512 G03

2.8

3.0

–25

25

75

125