LT1946

2

sn1946 1946fs

SW Voltage ............................................... – 0.4V to 36V

FB Voltage ............................................................. 2.5V

SHDN Voltage ......................................................... 16V

Current Into FB Pin ..............................................

±1mA

Maximum Junction Temperature ......................... 125

°C

Operating Temperature Range (Note 2) .. – 40

°C to 85°C

Storage Temperature Range ................ – 65

°C to 150°C

Lead Temperature (Soldering, 10 sec)................. 300

°C

ORDER PART

NUMBER

MS8 PART MARKING

(4-LAYER BOARD)

LTUG

LT1946EMS8

(Note 1)

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Minimum Operating Voltage

2.45

2.6

V

Maximum Operating Voltage

16

V

Feedback Voltage

1.230

1.250

1.270

V

q

1.220

1.270

V

FB Pin Bias Current

q

20

120

nA

Error Amp Transconductance

∆I = 2µA40

µmhos

Error Amp Voltage Gain

300

V/V

Quiescent Current

3.2

5

mA

Quiescent Current in Shutdown

0

1

µA

Reference Line Regulation

2.6V

0.01

0.05

%/V

Switching Frequency

0.9

1.2

1.4

MHz

q

0.8

1.5

MHz

Switching Frequency in Foldback

0.4

MHz

Maximum Duty Cycle

q

86

90

%

Switch Current Limit

(Note 4)

q

1.5

2.1

3.1

A

240

340

mV

Switch Leakage Current

0.01

1

µA

Soft-Start Charging Current

2.5

4

6

µA

SHDN Input Voltage High

2.4

V

SHDN Input Voltage Low

0.5

V

SHDN Pin Bias Current

16

32

µA

0

0.1

µA

ABSOLUTE

AXI U

RATI GS

PACKAGE/ORDER I FOR ATIO

ELECTRICAL CHARACTERISTICS

Consult LTC Marketing for parts specified with wider operating temperature ranges.

1

2

3

4

FB

SHDN

GND

8

7

6

5

SS

COMP

SW

TOP VIEW

MS8 PACKAGE

8-LEAD PLASTIC MSOP

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

of a device may be impaired.

Note 2: The LT1946E is guaranteed to meet performance specifications

from 0

°C to 70°C. Specifications over the –40°C to 85°C operating

temperature range are assured by design, characterization and correlation

with statistical process controls.

Note 3: Current flows out of FB pin.

Note 4: Current limit guaranteed by design and/or correlation to static test.

Current limit is independent of duty cycle and is guaranteed by design.