3

LTC3448

3448f

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Input DC Bias Current

Active Mode (Pulse Skip, No LRO)

250

375

µA

275

400

µA

Linear Regulator Operation (LRO)

32

43

µA

Shutdown

0.1

1

µA

Oscillator Frequency

●

1.2

1.5

1.8

MHz

FREQ = High

●

1.8

2.25

2.7

MHz

Synchronization Frequency

(Note 6)

1.5

>4

MHz

SYNC Activation Input Threshold

1

1.3

V

0.4

Ω

0.35

Ω

SW Leakage

±0.01

±1

µA

RUN Threshold High

●

1.5

V

RUN Threshold Low

●

0.3

V

RUN Leakage Current

●

±0.01

±1

µA

FREQ Threshold High

●

V

FREQ Threshold Low

●

1V

FREQ Leakage Current

●

±0.01

±1

µA

MODE Threshold High

V

MODE Threshold Low

●

0.12

V

MODE Leakage Current

●

±0.1

±1

µA

SYNC Leakage Current

●

±0.01

±1

µA

LRO ON Load Current Threshold

2.2mH Inductor (Note 8)

3

5

mA

LRO OFF Load Current Threhold

8

11

17

mA

The

ELECTRICAL CHARACTERISTICS

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

of a device may be impaired.

Note 2: The LTC3448E 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 4: The LTC3448 is tested in a proprietary test mode that connects

Note 5: Dynamic supply current is higher due to the gate charge being

delivered at the switching frequency. LRO is “linear regulator operation.”

Note 6: 4MHz operation is guaranteed by design but is not production

tested and is subject to duty cycle limitations.

Note 7: This IC includes overtemperature protection that is intended to

protect the device during momentary overload conditions. Junction

temperature will exceed 125

°C when overtemperature is active. Continu-

ous operation above the specified maximum operating junction tempera-

ture may impair device reliability.

Note 8: The load current below which the switching regulator turns off and

the LDO turns on is, to first order, inversely proportional to the value of

the inductor. This effect is covered in more detail in the Operation section.

This parameter is not production tested but is guaranteed by design.

to ensure regulation in linear regulator mode. This parameter is not

production tested but is guaranteed by design.