LTM4676A datasheet(4/22 Pages) LINER

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LTC3870

3870fb

For more information www.linear.com/LTC3870

Typical perForMance characTerisTics

Efficiency vs Load Current

Full Load Efficiency and Power

Loss vs Input Voltage

elecTrical characTerisTics The

denotes the specifications which apply over the specified operating

junction temperature range, otherwise specifications are at TA = 25°C. (Note 2) VIN = 15V, VRUN0,VRUN1 = 3.3V, fSYNC = 350kHz

(externally driven) unless otherwise specified.

Note 1: Stresses beyond those listed in 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 LTC3870 is tested under pulsed load conditions such that

TJ ≈ TA. The LTC3870E is guaranteed to meet specifications from

0°C to 85°C junction temperature. Specifications over the –40°C to

125°C operating junction temperature range are assured by design,

characterization and correlation with statistical process controls. The

LTC3870I is guaranteed over the full –40°C to 125°C operating junction

temperature range. Note that the maximum ambient temperature

consistent with these specifications is determined by specific operating

conditions in conjunction with board layout, the related package thermal

impedance and other environmental factors. The junction temperature TJ

is calculated from the ambient temperature TA and power dissipation PD

according to the following formula:

TJ = TA + (PD • 43°C/W)

Note 3: When VIN >15V, EXTVCC is recommended to reduce IC

Temperature.

Note 4: Output voltage is set and controlled by the master controller in

multiphase operations.

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

delivered at the switching frequency. See Application Information.

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

times are measured using 50% levels.

Note 7: The minimum on-time condition corresponds to an inductor

peak-to-peak ripple current ≥40% of IMAX (see Minimum On-Time

Considerations in the Applications Information section.

Note 8: EXTVCC is enabled only if VIN is higher than 6.5V.

Note 9: Guaranteed by design.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Digital Inputs RUN0/RUN1, MODE0/MODE1, FAULT0/FAULT1

VIH

Input High Threshold Voltage

2.0

VIL

Input Low Threshold Voltage

1.4

LOAD CURRENT (A)

0.1

100

3870 G01

CCM

DCM

VIN = 12V

VOUT = 1.8V

fSW = 400kHz

L = 0.56µH

DCR = 1.8m

LOAD CURRENT (A)

0.1

100

3870 G02

CCM

DCM

VIN = 12V

VOUT = 3.3V

fSW = 400kHz

L = 0.56µH

DCR = 1.8m

INPUT VOLTAGE (V)

2.5

1.5

0.5

3870 G03

EFFICIENCY

POWER LOSS

VIN = 12V

VOUT = 1.8V

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