Datasheet

LT4256-3
3
42563fa
V
FB
FB Voltage Threshold FB High-to-Low Transition ● 3.95 3.99 4.03 V
FB Low-to-High Transition
● 4.20 4.45 4.65 V
V
FBHYS
FB Hysteresis Voltage 0.3 0.45 0.60 V
V
OLPGD
PWRGD Output Low Voltage I
O
= 1.6mA 0.25 0.4 V
I
O
= 5mA 0.60 1.0 V
I
PWRGD
PWRGD Pin Leakage Current V
PWRGD
= 80V 0.1 1 µA
I
INFB
FB Input Current FB = 4.5V –0.1 –1 µA
I
TIMERPU
TIMER Pull-Up Current TIMER = 3V, During Fault ● – 63 – 105 –147 µA
I
TIMERPD
TIMER Pull-Down Current TIMER = 3V ● 1.5 3 5 µA
V
THTIMER
TIMER Shutdown Threshold C
TIMER
= 10nF ● 4.3 4.65 5 V
D
TIMER
Duty Cycle (RETRY Mode) ● 1.5 3 4.5 %
V
RETRYTH
RETRY Threshold ● 0.4 0.85 1.2 V
I
INRTR
RETRY Input Current RETRY = GND –87 –130 µA
t
PHLUV
UV Low to GATE Low C
GATE
= 100pF 1.7 3 µs
t
PLHUV
UV High to GATE High C
GATE
= 100pF 6 9 µs
t
PHLFB
FB Low to PWRGD Low 0.8 2 µs
t
PLHFB
FB High to PWRGD High 3.2 5 µs
t
PHLSENSE
(V
CC
– V
SENSE
) High to GATE Low V
CC
– V
SENSE
= 275mV 1 3 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
= 48V 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 minimum of 10V above
V
CC
. Driving this pin to a voltage beyond the clamp voltage may damage
the part.
TYPICAL PERFOR A CE CHARACTERISTICS
UW
I
CC
vs Temperature
SENSE Regulation Voltage
vs Temperature I
CC
vs V
CC
TEMPERATURE (°C)
–50
10
SENSE REGULATION VOLTAGE (mV)
15
20
48
58
–25
02550
42563 G01
75
100
53
FB = 0V
FB > 2V
V
CC
(V)
10
2.0
2.5
3.5
40 60
42563 G02
1.5
1.0
20 30
50 70 80
0.5
0
3.0
I
CC
(mA)
TEMPERATURE (°C)
–50
0
I
CC
(mA)
0.5
1.0
1.5
2.5
–25
02550
42563 G03
75
100
2.0
V
CC
= 48V
Specifications are at T
A
= 25°C unless otherwise noted.