LT1952/LT1952-1
5
19521fe
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 LT1952/LT1952-1 are tested under pulsed load conditions
such that T
J
≈ T
A
. 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 –40°C to 125°C operating junction temperature range and the
LT1952MPGN/LT1952MPGN-1 are tested and guaranteed over the full
–55°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 rated package thermal impedance and other environmental
factors.
Note 3: Rise and Fall times are measured at 10% and 90% levels.
Note 4: Guaranteed by correlation to static test.
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 V
IN
pin is supplied via an external RC
network from a SYSTEM V
IN
> 25V, an external zener with clamp voltage
V
IN ON(MAX)
< V
Z
< 25V should be connected from the V
IN
pin to ground.
Note 9: V
IN
start-up current is measured at V
IN
= V
IN ON
– 0.25V and
scaled by x 1.18 (to correlate to worst case V
IN
start-up current at V
IN ON
).
Note 10: Timing for R = 40k derived from measurement with R = 240k.
The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). COMP = open, FB = 1.4V, R
OSC
= 178k, SYNC = 0V,
SS_MAXDC = V
REF
, V
REF
= 0.1µF, SD_V
SEC
= 2V, BLANK = 121k, DELAY = 121k, I
SENSE
= 0V, OC = 0V, OUT = 1nF, V
IN
= 15V, SOUT =
open, unless otherwise specified.
ELECTRICAL CHARACTERISTICS
PARAMETER CONDITIONS MIN TYP MAX UNITS
SOFT-START
SS_MAXDC Low Level: V
OL
I
(SS_MAXDC)
= 150µA, OC = 1V 0.2 V
SS_MAXDC Soft-Start Reset Threshold Measured on SS_MAXDC 0.45 V
SS_MAXDC Active Threshold FB = 1V, DC > 0% 0.8 V
SS_MAXDC Input Current (Soft-Start Pull-Down: Idis) SS_MAXDC = 1V, SD_V
SEC
= 1.4V, OC = 1V 800 µA
