Datasheet

LT4254
3
4254fb
T
A
= 25°C
V
CC
(V)
10
1.0
I
CC
(mA)
1.5
2.0
2.5
3.0
15 20 25 30
4254 G03
35 40
I
PWRGD
PWRGD Pin Leakage Current V
PWRGD
= 36V 0.1 10 µA
I
INFB
FB Input Current FB = 4.5V –1 –0.1 µA
I
TIMERPU
TIMER Pull-Up Current ● – 60 –120 –180 µA
I
TIMERPD
TIMER Pull-Down Current ● 135 µA
V
THTIMER
TIMER Shut-Down Threshold Voltage C
TIMER
= 10nF ● 4.3 4.65 5 V
D
TIMER
Duty Cycle (RETRY Mode) ● 1.5 3 4.5 %
V
RETRY(TH)
RETRY Threshold ● 0.4 0.8 1.2 V
I
INRTR
RETRY Input Current RETRY = GND –120 –85 –40 µA
t
PHLUV
UV Low to GATE Low C
GATE
= 100pF 1.7 µs
t
PLHUV
UV High to GATE High C
GATE
= 100pF 6 µs
t
PHLFB
FB Low to PWRGD Low 0.8 µs
t
PLHFB
FB High to PWRGD High 3.2 µs
t
PHLSENSE
(V
CC
– V
SENSE
) High to GATE Low V
CC
– V
SENSE
= 275mV 2.5 4 µs
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 24V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: An internal clamp limits the GATE pin to a maximum of 11V above
V
CC
(under normal operating conditions). Driving this pin to a voltage
beyond the clamp voltage may damage the part.
TYPICAL PERFOR A CE CHARACTERISTICS
UW
I
CC
vs V
CC
SENSE Pin Regulation Voltage
vs Temperature, FB = 0V
SENSE Pin Regulation Voltage
vs Temperature, FB > 2V
TEMPERATURE (°C)
–50
SENSE REGULATION VOLTAGE (mV)
13
15
17
25 75
4254 G01
11
9
–25 0
50 100 125
7
5
TEMPERATURE (°C)
–50
40
SENSE REGULATION VOLTAGE (mV)
45
50
55
60
–25 0 25 50
4254 G02
75 100 125