LT3509
3
3509fd
For more information www.linear.com/LT3509
elecTrical characTerisTics
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. Absolute Maximum Voltage at the V
IN
pin is 60V for non-repetitive
1 second transients and 36V for continuous operation.
Note 3. The LT3509E is 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 LT3509I is guaranteed
over the full –40°C to 125°C temperature range. The LT3509H is guaranteed
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
IN
= 12V. (Note 3)
PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Undervoltage Lockout 3.3 3.6 V
V
IN
Overvoltage Lockout 37 38.5 40 V
Input Quiescent Current Not Switching V
FB
> 0.8V 1.9 2.2 mA
Input Shutdown Current V(RUN/SS[1,2]) < 0.3V 9 15 µA
Feedback Pin Voltage
l
0.784 0.8 0.816 V
Reference Voltage Line Regulation 3.6V < V
IN
< 36V 0.01 %/V
RUN/SS Shutdown Threshold 0.4 0.6 0.8 V
RUN/SS Voltage for Full I
OUT
2 V
RUN/SS Pin Pull-up Current 0.7 1 1.3 µA
Feedback Pin Bias Current (Note 4) V
FB
= 0.8V
l
90 500 nA
Switch Current Limit
l
1.05 1.4 1.9 A
DA Comparator Current Threshold 0.7 0.95 1.2 A
Boost Pin Current I
SW
= 0.9A 22 36 mA
Switch Leakage Current 0.01 1.0 µA
Switch Saturation Voltage I
SW
= 0.9A (Note 5) 0.32 V
Minumum Boost Voltage above Switch I
SW
= 0.9A 1.5 2.2 V
Boost Diode Forward Voltage I
BD
= 20mA 0.7 0.9 V
Boost Diode Leakage V
R
= 30V 0.1 5 µA
Switching Frequency R
T
= 40.2kΩ
R
T
= 180kΩ
R
T
= 14.1kΩ
l
0.92
237
2.0
1.0
260
2.15
1.08
290
2.5
MHz
kHz
MHz
Sync Pin Input Threshold 1.0 V
Switch Minimum Off-Time
l
80 150 ns
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 4. Current flows out of pin.
Note 5. Switch Saturation Voltage is guaranteed by design.
Note 6. This IC includes overtemperature protection that is intended to protect
the device during momentary overload conditions. Junction temperature will
exceed the maximum operating temperature when overtemperature protection
is active. Continuous operation above the specified maximum operating
junction temperature may impair device reliability.
