LT4256-1/LT4256-2
2
425612fa
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
(Note 1)
Supply Voltage (V
CC
) ................................ –0.3 to 100V
SENSE, PWRGD ....................................... – 0.3 to 100V
GATE (Note 2) ................................ –0.3V to V
CC
+ 10V
Maximum Input Current (GATE) ......................... 200µA
FB, UV ........................................................ – 0.3 to 44V
TIMER ..................................................... –0.3V to 4.3V
Maximum Input Current (TIMER) ....................... 100µA
Operating Temperature
LT4256C ................................................. 0°C to 70°C
LT4256I ............................................. –40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ABSOLUTE AXI U RATI GS
W
WW
U
Consult LTC Marketing for parts specified with wider operating temperature ranges.
PACKAGE/ORDER I FOR ATIO
UUW
ORDER PART
NUMBER
S8 PART MARKING
42561
42561I
42562
42562I
LT4256-1CS8
LT4256-1IS8
LT4256-2CS8
LT4256-2IS8
T
JMAX
= 125°C, θ
JA
= 110°C/W
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
V
CC
Operating Voltage ● 10.8 80 V
I
CC
Operating Current 1.8 3.9 mA
V
UVLH
Undervoltage Threshold V
CC
Low-to-High Transition ● 3.96 4 4.04 V
V
UVHYS
Hysteresis 0.25 0.4 0.55 V
I
INUV
UV Input Current UV ≥ 1.2V –0.1 –1 µA
UV = 0V –1.5 –3 µA
V
UVRTH
Fault Latch Reset Threshold Voltage ● 0.4 0.85 1.2 V
V
SENSETRIP
SENSE Pin Trip Voltage (V
CC
– V
SENSE
) FB = 0V ● 5.5 14 22 mV
FB ≥ 2V
● 45 55 65 mV
I
INSNS
SENSE Pin Input Current V
SENSE
= V
CC
40 70 µA
I
PU
GATE Pull-Up Current Charge Pump On, ∆V
GATE
= 7V ● –16 –32 –63 µA
I
PD
GATE Pull-Down Current Any Fault, V
GATE
= 3V 40 62 80 mA
∆V
GATE
External N-Channel Gate Drive (Note 2) V
GATE
– V
CC
, 10.8V ≤ V
CC
≤ 20V ● 4.5 8.8 12.5 V
20V ≤ V
CC
≤ 80V ● 10 11.6 12.8 V
V
FB
FB Voltage Threshold FB High-to-Low Transition ● 3.95 3.99 4.03 V
FB Low-to-High Transition
● 4.2 4.45 4.65 V
V
FBHYS
FB Hysteresis Voltage 0.3 0.45 0.6 V
V
OLPGD
PWRGD Output Low Voltage I
O
= 1.6mA 0.25 0.4 V
I
O
= 5mA 0.6 1 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 Shut-Down Threshold C
TIMER
= 10nF ● 4.3 4.65 5 V
D
TIMER
Duty Cycle (RETRY Mode) ● 1.5 3 4.5 %
1
2
3
4
8
7
6
5
TOP VIEW
V
CC
SENSE
GATE
TIMER
UV
FB
PWRGD
GND
S8 PACKAGE
8-LEAD PLASTIC SO
