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LT3757
4
3757fc
TEMPERATURE (°C)
–75 –50
1580
1585
REGULATED
FEEDBACK
VOLTAGE
(mV)
1590
1605
1600
0
50 75
1595
–25
25
100
150
125
3757 G01
VIN = 40V
VIN = 24V
VIN = 8V
VIN = INTVCC = 2.9V
SHDN/UVLO = 1.33V
TEMPERATURE (°C)
REGULATED
FEEDBACK
VOLTAGE
(mV)
–802
–800
–798
–788
–790
–792
–794
–804
–796
3757 G02
–75 –50
0
50 75
–25
25
100
150
125
VIN = 40V
VIN = 24V
VIN = 8V
VIN = INTVCC = 2.9V
SHDN/UVLO = 1.33V
Typical perForMance characTerisTics
Positive Feedback Voltage
vs Temperature, VIN
Negative Feedback Voltage
vs Temperature, VIN
Quiescent Current
vs Temperature, VIN
TA = 25°C, unless otherwise noted.
elecTrical characTerisTics The
l
denotes the specifications which apply over the full operating temp-
erature range, otherwise specifications are at TA = 25°C. VIN = 24V, SHDN/UVLO = 24V, SENSE = 0V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
INTVCC Current in Shutdown
SHDN/UVLO = 0V, INTVCC = 8V
16
A
INTVCC Voltage to Bypass Internal LDO
7.5
V
Logic Inputs
SHDN/UVLO Threshold Voltage Falling
VIN = INTVCC = 8V
l
1.17
1.22
1.27
V
SHDN/UVLO Input Low Voltage
I(VIN) Drops Below 1A
0.4
V
SHDN/UVLO Pin Bias Current Low
SHDN/UVLO = 1.15V
1.7
2
2.5
A
SHDN/UVLO Pin Bias Current High
SHDN/UVLO = 1.30V
10
100
nA
Gate Driver
tr Gate Driver Output Rise Time
CL = 3300pF (Note 5), INTVCC = 7.5V
22
ns
tf Gate Driver Output Fall Time
CL = 3300pF (Note 5), INTVCC = 7.5V
20
ns
Gate VOL
0.05
V
Gate VOH
INTVCC
–0.05
V
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 LT3757E is guaranteed to meet performance specifications
from the 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
LT3757I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT3757H is guaranteed over the full –40°C to 150°C
operating junction temperature range. High junction temperatures degrade
operating lifetimes. Operating lifetime is derated at junction temperatures
greater than 125°C. The LT3757MP is 100% tested and guaranteed over the
full –55°C to 150°C operating junction temperature range.
Note 3: The LT3757 is tested in a feedback loop which servos VFBX to the
reference voltages (1.6V and –0.8V) with the VC pin forced to 1.3V.
Note 4: FBX overvoltage lockout is measured at VFBX(OVERVOLTAGE) relative
to regulated VFBX(REG).
Note 5: Rise and fall times are measured at 10% and 90% levels.
Note 6: For VIN below 6V, the SHDN/UVLO pin must not exceed VIN.
Note 7: SHDN/UVLO = 1.33V when VIN = 2.9V.
Note 8: The LT3757 includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed the maximum operating junction temperature
when overtemperature protection is active. Continuous operation above
the specified maximum operating junction temperature may impair device
reliability.
–75 –50
0
50 75
–25
25
100
150
125
TEMPERATURE (°C)
1.4
QUIESCENT
CURRENT
(mA)
1.6
1.8
1.5
1.7
3757 G03
VIN = 40V
VIN = 24V
VIN = INTVCC = 2.9V