LT1952 Linear Technology, LT1952 Datasheet - Page 4

• Manufacturer Part Number: LT1952
• Description: Single Switch Synchronous Forward Controller
• Manufacturer: Linear Technology

LT1952
ELECTRICAL CHARACTERISTICS
OUT Max Duty Cycle
OUT Max Duty Cycle Clamp
SOFT-START
SS_MAXDC Low Level: V
SS_MAXDC Soft-Start Reset Threshold
SS_MAXDC Active Threshold
SS_MAXDC Input Current (Soft-Start Pulldown: Idis)
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1952EGN is 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 is 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.
Note 5: This IC includes over-temperature protection that is intended to
protect the device during momentary overload conditions. Junction
temperature range, otherwise specifications are at T
V
specified.
PARAMETER
4
REF
= 0.1µF, SD_V
SEC
OL
= 2V, BLANK = 40k, DELAY = 40k, I
COMP = 2.5V, FB = 1V, R
(f
SD_V
COMP = 2.5V, FB = 1V, R
(f
SD_V
SD_V
I
Measured on SS_MAXDC
FB = 1V, DC > 0%
SS_MAXDC = 1V, SD_V
CONDITIONS
(SS_MAXDC)
OSC
OSC
A
= 25°C. COMP = open, FB = 1.4V, R
= 200kHz)
SEC
= 200kHz)
SEC
SEC
SENSE
The
= 1.4V, SS_MAXDC = V
= 1.32V, SS_MAXDC = 1.84V
= 2.64V, SS_MAXDC = 1.84V
= 150µA, OC = 1V
●
= 0V, OC = 0V, OUT = 1nF, V
denotes the specifications which apply over the full operating
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
network from a SYSTEM V
V
Note 9: V
scaled by x 1.18 (to correlate to worst case V
Note 10: Timing for R = 40k derived from measurement with R = 240k.
IN ON(MAX)
SEC
DELAY
DELAY
= 1.4V, OC = 1V
IN
= 10k
= 10k
REF
< V
start-up current is measured at V
Z
< 25V should be connected from the V
OSC
IN
IN
= 178k, SYNC = 0V, SS_MAXDC = V
= 15V, SOUT = open, unless otherwise
> 25V, an external zener with clamp voltage
IN
63.5
MIN
pin is supplied via an external RC
83
25
www.DataSheet4U.com
IN
IN
= V
0.45
start-up current at V
TYP
800
0.2
0.8
72
33
90
IN ON
IN
– 0.25V and
pin to ground.
MAX
80.5
41
IN ON
UNITS
REF
1952f
,
µA
).
%
%
%
V
V
V