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LTC3872-1

38721f

For more information www.linear.com/LTC3872-1

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 LTC3872-1 is tested under pulsed load conditions such that

TJ ≈ TA. The LTC3872-1E is guaranteed to meet performance specifications

from 0°C to 85°C. Specifications over the –40°C to 85°C operating

junction temperature range are assured by design, characterization and

correlation with statistical process controls. The LTC3872-1I is guaranteed

over the –40°C to 125°C operating junction temperature range. The

LTC3872-1H is guaranteed over the full –40°C to 150°C operating junction

temperature range. The maximum ambient temperature consistent with

these specifications is determined by specific operating conditions in

conjunction with board layout, the rated package thermal impedance and

other environmental factors.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Input Voltage Range

2.75

9.8

Input DC Supply Current

Normal Operation

Shutdown

UVLO

Typicals at VIN = 4.2V (Note 4)

2.75V ≤ VIN ≤ 9.8V

VRUN/SS = 0V

VIN < UVLO Threshold

250

400

µA

Undervoltage Lockout Threshold

VIN Rising

VIN Falling

2.3

2.05

2.45

2.3

2.75

2.55

Shutdown Threshold (at RUN/SS)

VRUN/SS Falling

VRUN/SS Rising

0.6

0.65

0.85

0.95

1.05

1.15

Regulated Feedback Voltage

(Note 5) LTC3872-1E

LTC3872-1I and LTC3872-1H

1.182

1.178

1.2

1.218

Feedback Voltage Line Regulation

2.75V < VIN < 9V (Note 5)

0.14

mV/V

Feedback Voltage Load Regulation

VITH = 1.6V (Note 5)

VITH = 1V (Note 5)

0.05

–0.05

VFB Input Current

(Note 5)

RUN/SS Pull Up Current

VRUN/SS = 0

0.35

0.7

1.25

µA

Oscillator Frequency

Normal Operation

VFB = 1V

500

550

650

kHz

Gate Drive Rise Time

CLOAD = 3000pF

Gate Drive Fall Time

CLOAD = 3000pF

Peak Current Sense Voltage

IPRG = GND (Note 6)

LTC3872-1E

LTC3872-1I

LTC3872-1H

105

120

IPRG = Float

LTC3872-1E

LTC3872-1I

LTC3872-1H

160

150

145

180

200

IPRG = VIN

LTC3872-1E

LTC3872-1I

LTC3872-1H

260

250

240

285

310

Default Internal Soft-Start Time

The l denotes the specifications which apply over the specified operating

junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 4.2V unless otherwise noted.

Note 3: TJ is calculated from the ambient temperature TA and power

dissipation PD according to the following formula:

LTC3872-1TS8: TJ = TA + (PD • 195°C/W)

LTC3872-1DDB: TJ = TA + (PD • 76°C/W)

Note 4: The dynamic input supply current is higher due to power MOSFET

gate charging (QG • fOSC). See Applications Information.

Note 5: The LTC3872-1 is tested in a feedback loop which servos VFB to

the reference voltage with the ITH pin forced to the midpoint of its voltage

range (0.7V ≤ VITH ≤ 1.9V, midpoint = 1.3V).

Note 6: Rise and fall times are measured at 10% and 90% levels.

elecTrical characTerisTics

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