3

LTC1772

1772fb

TYPICAL PERFOR A CE CHARACTERISTICS

Reference Voltage

vs Temperature

Normalized Frequency

vs Temperature

Undervoltage Lockout Trip

Voltage vs Temperature

TEMPERATURE (

°C)

–55 –35 –15

5

25

45

65

85 105 125 145

1772 G01

825

820

815

810

805

800

795

790

785

780

775

TEMPERATURE (

°C)

–55 –35 –15

5

25

45

65

85 105 125 145

1772 G02

10

8

6

4

2

0

–2

–4

–6

–8

–10

DUTY CYCLE (%)

20

30

40

50

60

70

80

90

100

1772 G04

130

120

110

100

90

80

70

60

50

vs Duty Cycle

Shutdown Threshold

vs Temperature

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

of a device may be impaired.

Note 2: The LTC1772E is guaranteed to meet specifications from 0

°Cto

70

°C. Specifications over the –40°C to 85°C operating temperature range

are assured by design, characterization and correlation with statistical

process controls. The LTC1772I is guaranteed to meet specified

performance from –40

°C to 85°C. The LTC1772H is guaranteed to meet

specified performance from –40

°C to 140°C.

Operation at high junction temperatures degrades operating lifetimes.

Operating lifetimes at junction temperatures greater than 125

°C is derated

to 1000 hours.

Note 4: Dynamic supply current is higher due to the gate charge being

delivered at the switching frequency.

output of the error amplifier.

Note 6: Peak current sense voltage is reduced dependent on duty cycle to

a percentage of value as given in Figure 2.

TEMPERATURE (

°C)

–55 –35 –15

5

25

45

65

85 105 125 145

1772 G05

550

510

470

430

390

350

310

270

230

190

150

TEMPERATURE (

°C)

–55 –35 –15

5

25

45

65

85 105 125 145

1772 G03

2.14

2.10

2.06

2.02

1.98

1.94

1.90

1.86

1.82

1.78

1.74

ELECTRICAL CHARACTERISTICS