LT3757/LT3757A

4

Rev. G

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ELECTRICAL CHARACTERISTICS The

l

denotes the specifications which apply over the full operating temp-

erature range, otherwise specifications are at TA = 25°C. VIN = 24V, SHDN/UVLO = 24V, SENSE = 0V, unless otherwise noted.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

SYNC Input Low

0.4

V

SYNC Input High

1.5

V

SS Pull-Up Current

SS = 0V, Current Out of Pin

–10

µA

Low Dropout Regulator

INTVCC Regulation Voltage

l

7

7.2

7.4

V

INTVCC Undervoltage Lockout Threshold

Falling INTVCC

UVLO Hysteresis

2.6

2.7

0.1

2.8

V

V

INTVCC Overvoltage Lockout Threshold

16

17.5

V

INTVCC Current Limit

VIN = 40V

VIN = 15V

30

40

95

55

mA

mA

INTVCC Load Regulation (∆VINTVCC/VINTVCC)

0 < IINTVCC < 20mA, VIN = 8V

–0.9

–0.5

%

INTVCC Line Regulation ∆VINTVCC/(VINTVCC • ∆VIN)

8V < VIN < 40V

0.008

0.03

%/V

Dropout Voltage (VIN – VINTVCC)

VIN = 6V, IINTVCC = 20mA

400

mV

INTVCC Current in Shutdown

SHDN/UVLO = 0V, INTVCC = 8V

16

µA

INTVCC Voltage to Bypass Internal LDO

7.5

V

Logic Inputs

SHDN/UVLO Threshold Voltage Falling

VIN = INTVCC = 8V

l

1.17

1.22

1.27

V

SHDN/UVLO Input Low Voltage

I(VIN) Drops Below 1µA

0.4

V

SHDN/UVLO Pin Bias Current Low

SHDN/UVLO = 1.15V

1.7

2

2.5

µA

SHDN/UVLO Pin Bias Current High

SHDN/UVLO = 1.30V

10

100

nA

Gate Driver

tr Gate Driver Output Rise Time

CL = 3300pF (Note 5), INTVCC = 7.5V

22

ns

tf Gate Driver Output Fall Time

CL = 3300pF (Note 5), INTVCC = 7.5V

20

ns

Gate VOL

0.05

V

Gate VOH

INTVCC –0.05

V

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 LT3757E/LT3757AE are guaranteed to meet performance

specifications from the 0°C to 125°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 LT3757I/LT3757AI are guaranteed over the full –40°C to

125°C operating junction temperature range. The LT3757H/LT3757AH are

guaranteed over the full –40°C to 150°C operating junction temperature

range. High junction temperatures degrade operating lifetimes. Operating

lifetime is derated at junction temperatures greater than 125°C. The

LT3757MP/LT3757AMP are 100% tested and guaranteed over the full

–55°C to 150°C operating junction temperature range.

Note 3: The LT3757/LT3757A are tested in a feedback loop which servos

VFBX to the reference voltages (1.6V and –0.8V) with the VC pin forced

to 1.3V.

Note 4: FBX overvoltage lockout is measured at VFBX(OVERVOLTAGE) relative

to regulated VFBX(REG).

Note 5: Rise and fall times are measured at 10% and 90% levels.

Note 6: For VIN below 6V, the SHDN/UVLO pin must not exceed VIN.

Note 7: SHDN/UVLO = 1.33V when VIN = 2.9V.

Note 8: The LT3757/LT3757A include overtemperature protection that

is intended to protect the device during momentary overload conditions.

Junction temperature will exceed the maximum operating junction

temperature when overtemperature protection is active. Continuous

operation above the specified maximum operating junction temperature

may impair device reliability.