LT1952IGN datasheet(4/24 Pages) LINER

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LT1952/LT1952-1

19521fd

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 LT1952EGN/LT1952EGN-1 are guaranteed to meet

performance speciﬁcations from 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 LT1952IGN/LT1952IGN-1 are guaranteed

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

Note 3: Rise and Fall times are measured at 10% and 90% levels.

Note 4: Guaranteed by correlation to static test.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

SOUT DRIVER

SOUT Clamp Voltage

I(GATE) = 0μA, COMP = 2.5V, FB = 1V

10.5

13.5

SOUT Low Level

I(GATE) = 25mA

0.5

0.75

SOUT High Level

I(GATE) = –25mA, VIN = 12V, COMP = 2.5V,

FB = 1V

SOUT Active Pull-Off in Shutdown

VIN = 5V, SD_VSEC = 0V, SOUT = 1V

SOUT to OUT (Rise) DELAY (tDELAY)

COMP = 2.5V, FB = 1V (Note 10)

RDELAY = 120k

120

VDELAY

0.9

OUT DRIVER

OUT Rise Time

FB = 1V, CL = 1nF (Notes 3, 6)

OUT Fall Time

FB = 1V, CL = 1nF (Notes 3, 6)

OUT Clamp Voltage

I(GATE) = 0μA, COMP = 2.5V, FB = 1V

11.5

14.5

OUT Low Level

I(GATE) = 20mA

I(GATE) = 200mA

0.45

1.25

0.75

1.8

OUT High Level

I(GATE) = –20mA, VIN = 12V, COMP = 2.5V,

FB = 1V

I(GATE) = –200mA, VIN = 12V, COMP = 2.5V,

FB = 1V

9.9

9.75

OUT Active Pull-Off in Shutdown

VIN = 5V, SD_VSEC = 0V, OUT = 1V

OUT Max Duty Cycle

COMP = 2.5V, FB = 1V, RDELAY = 10k

(fOSC = 200kHz), VIN = 10V

SD_VSEC = 1.4V, SS_MAXDC = VREF

OUT Max Duty Cycle Clamp

COMP = 2.5V, FB = 1V, RDELAY = 10k

(fOSC = 200kHz), VIN = 10V

SD_VSEC = 1.32V, SS_MAXDC = 1.84V

SD_VSEC = 2.64V, SS_MAXDC = 1.84V

63.5

80.5

SOFT-START

SS_MAXDC Low Level: VOL

I(SS_MAXDC) = 150μA, OC = 1V

0.2

SS_MAXDC Soft-Start Reset Threshold

Measured on SS_MAXDC

0.45

SS_MAXDC Active Threshold

FB = 1V, DC > 0%

0.8

SS_MAXDC Input Current (Soft-Start Pull-Down: Idis)

SS_MAXDC = 1V, SD_VSEC = 1.4V, OC = 1V

800

μA

Note 5: Each IC includes over-temperature protection that is intended

to protect the device during momentary overload conditions. Junction

temperature will exceed 125°C when over-temperature protection is active.

Continuous operation above the speciﬁed maximum operating junction

temperature may impair device reliability.

Note 6: Guaranteed but not tested.

Note 7: Maximum recommended SYNC frequency = 500kHz.

Note 8: In applications where the VIN pin is supplied via an external RC

network from a SYSTEM VIN > 25V, an external zener with clamp voltage

VIN ON(MAX) < VZ < 25V should be connected from the VIN pin to ground.

Note 9: VIN start-up current is measured at VIN = VIN ON – 0.25V and

scaled by x 1.18 (to correlate to worst case VIN start-up current at VIN ON).

Note 10: Timing for R = 40k derived from measurement with R = 240k.

The

l denotes the speciﬁcations which apply over the full operating

temperature range, otherwise speciﬁcations are at TA = 25°C. COMP = open, FB = 1.4V, ROSC = 178k, SYNC = 0V, SS_MAXDC = VREF, VREF

= 0.1μF, SD_VSEC = 2V, BLANK = 121k, DELAY = 121k, ISENSE = 0V, OC = 0V, OUT = 1nF, VIN = 15V, SOUT = open, unless otherwise speciﬁed.

ELECTRICAL CHARACTERISTICS

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