LT3755/LT3755-1/LT3755-2
4
37551fd
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 24V, SHDN/UVLO = 24V, CTRL = 2V, PWM = 5V, unless otherwise noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Linear Regulator
INTV
CC
Regulation Voltage 7 7.15 7.3 V
Dropout (V
IN
– INTV
CC
) I
INTVCC
= –10mA, V
IN
= 7V 350 mV
INTV
CC
Undervoltage Lockout 3.9 4.1 4.3 V
INTV
CC
Current Limit 29 34 40 mA
INTV
CC
Current in Shutdown SHDN/UVLO = 0V, INTV
CC
= 7V 8 12 µA
Logic Inputs/Outputs
PWM Input High Voltage
l
1.5 V
PWM Input Low Voltage
l
0.4 V
PWM Pin Resistance to GND 45 60 kΩ
PWMOUT Output Low (V
OL
) 0 50 mV
PWMOUT Output High (V
OH
) INTV
CC
–
0.05
V
SHDN/UVLO Threshold Voltage Falling E-, I-Grades
H-Grade
l
l
1.185
1.175
1.220 1.245
1.245
V
V
SHDN/UVLO Rising Hysteresis 20 mV
SHDN/UVLO Input Low Voltage I
VIN
Drops Below 1µA 0.4 V
SHDN/UVLO Pin Bias Current Low SHDN/UVLO = 1.15V 1.7 2.05 2.5 µA
SHDN/UVLO Pin Bias Current High SHDN/UVLO = 1.30V 10 100 nA
OPENLED Output Low (V
OL
) I
OPENLED
= 0.5mA (LT3755 and LT3755-2) 200 mV
SYNC Pin Resistance to GND LT3755-1 Only 30 kΩ
SYNC Input High LT3755-1 Only 1.5 V
SYNC Input Low LT3755-1 Only 0.4 V
Gate Driver
t
r
GATE Driver Output Rise Time C
L
= 3300pF 35 ns
t
f
GATE Driver Output Fall Time C
L
= 3300pF 35 ns
GATE Output Low (V
OL
) 0.05 V
GATE Output High (V
OH
) INTV
CC
–
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 LT3755E, LT3755E-1 and LT3755E-2 are 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 LT3755I, LT3755I-1 and LT3755I-2 are
guaranteed to meet performance specifications over the –40°C to 125°C
operating junction temperature range. The LT3755H-2 is guaranteed to
meet performance specifications 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.
Note 3: For V
IN
below 6V, the SHDN/UVLO pin must not exceed V
IN
for
proper operation.
Note 4: GATE and PWMOUT pins are driven either to GND or INTV
CC
by
internal switches. Do not connect these pins externally to a power supply.
Note 5: The LT3755 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 operating above
the specified maximum operating junction temperature may impair device
reliability.
