LTC4449 datasheet(4/38 Pages) LINER

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LTC3774

3774fc

For more information www.linear.com/LTC3774

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, VRUN = 5V unless otherwise specified.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

VPG(HYST)

PGOOD Trip Level Hysteresis

INTVCC Linear Regulator

VINTVCC

Linear Regulator Voltage

6V < VIN < 38V

5.3

5.5

5.7

VLDO INT

INTVCC Load Regulation

ICC = 0mA to 20mA

0.5

Oscillator and Phase-Locked Loop

fOSC

Oscillator Frequency

VPHSMD = 0V

RFREQ < 23.2kΩ

RFREQ = 30.1kΩ

RFREQ = 47.5kΩ

RFREQ = 54.9kΩ

RFREQ = 75.0kΩ

Maximum Frequency

Minimum Frequency

540

1.2

150

250

600

750

1.05

660

0.2

kHz

MHz

IFREQ

FREQ Pin Output Current

VFREQ = 0.8V

µA

RMODE/PLLIN

MODE/PLLIN Input Resistance

250

kΩ

VMODE/PLLIN

PLLIN Input Threshold

VMODE/PLLIN Rising

VMODE/PLLIN Falling

1.2

VCLKOUT

Low Output Voltage

High Output Voltage

ILOAD = –500µA

ILOAD = 500µA

0.2

5.2

θ2 – θ1

Channel 1-2 Phase Delay

VPHSMD = 0V

VPHSMD = 1/4 INTVCC

VPHSMD = Float

VPHSMD = 3/4 INTVCC

VPHSMD = INTVCC

180

120

Deg

θCLKOUT – θ1

CLKOUT to Channel 1

Phase Delay

VPHSMD = 0V

VPHSMD = 1/4 INTVCC

VPHSMD = Float

VPHSMD = 3/4 INTVCC

VPHSMD = INTVCC

240

Deg

θ1 – θCLKIN

Channel 1 to CLKIN Phase Delay

VPHSMD = 0V

VPHSMD = 1/4 INTVCC

VPHSMD = Float

VPHSMD = 3/4 INTVCC

VPHSMD = INTVCC

Deg

PWM/PWMEN Outputs

PWM

PWM Output High Voltage

ILOAD = 500µA

5.0

PWM Output Low Voltage

ILOAD = –500µA

0.5

PWM Output Current in Hi-Z State

–5

µA

PWMEN

PWMEN Output High Voltage

ILOAD = 500µA

5.0

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 LTC3774 is tested under pulsed load conditions such that

TJ ≈ TA. The LTC3774E is guaranteed to meet performance specifications

from 0°C to 85°C operating 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 LTC3774I is guaranteed to meet performance specifications over the

full –40°C to 125°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 package

thermal impedance and other environmental factors.

TJ is calculated from the ambient temperature, TA, and power dissipation,

PD, according to the following formula:

LTC3774UHE: TJ = TA + (PD • 43°C/W)

Note 3: The LTC3774 is tested in a feedback loop that servos VITH to a

specified voltage and measures the resultant VFB.

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

delivered at the switching frequency. See Applications Information.

Note 5: Guaranteed by design.

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