LT3500
4
3500fc
PARAMETER CONDITIONS MIN TYP MAX UNITS
LFB Voltage V
LDRV
= V
LFB
l
0.784 0.8 0.816 V
LFB Line/Load Regulation V
VIN
= 3V to 40V, V
LDRV
= V
LFB
l
0.776 0.8 0.824 V
SS to LFB Offset (V
SS
– V
LFB
)V
SS
= 0.8V, V
LDRV
= V
LFB
90 115 140 mV
LFB Bias Current V
LFB
= 0.8V 115 300 nA
LDRV Dropout (V
VIN
– V
LDRV
)V
LDRV
= 3V, I
LDRV
= 5mA
l
0.8 1.2 1.6 V
LDRV Maximum Current V
LDRV
= 0V
l
91318mA
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
J
= 25°C. V
VIN
= 15V, V
RT/SYNC
= 2V, unless otherwise specifi ed.
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.
Note2: The LT3500EDD/LT3500EMSE is guaranteed to meet performance
specifi cations from 0°C to 125°C junction temperature. Specifi cations over
the –40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LT3500IDD/LT3500IMSE is guaranteed over the full –40°C to 125°C
operating junction temperature range. The LT3500HDD/LT3500HMSE 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.
Note 3: Minimum input voltage is defi ned as the voltage where internal
bias lines are regulated so that the reference voltage and oscillator remain
constant. Actual minimum input voltage to maintain a regulated output
will depend upon output voltage and load current. See Applications
Information.
Note 4: An internal power-on reset (POR) latch is set on the positive
transition of the SHDN pin through its threshold. The output of the latch
activates a current source on the SS pin which typically sinks 600µA,
discharging the SS capacitor. The latch is reset when the SS pin is driven
below the soft-start POR threshold or the SHDN pin is taken below its
threshold.
Note 5: This is the minimum voltage across the boost capacitor needed to
guarantee full saturation of the internal power switch.
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 junction temperature
when overtemperature protection is active. Continuous operation above
the specifi ed maximum operating junction temperature may impair device
reliability.
TYPICAL PERFORMANCE CHARACTERISTICS
Feedback Voltage vs Temperature
R
T
/SYNC Voltage vs Temperature
Shutdown Threshold and Minimum
Input Voltage vs Temperature
TEMPERATURE (°C)
–50
VOLTAGE (V)
0.800
FB
LFB
0.810
150
3500 G01
0.790
0.780
0
50
100
–25
25
75
125
0.820
0.795
0.805
0.785
0.815
TEMPERATURE (°C)
–50
0.90
VOLTAGE (V)
0.92
0.96
0.98
1.00
1.10
1.04
0
50
75
3500 G02
0.94
1.06
1.08
1.02
–25 25
100
125
150
R
RT/SYNC
= 90.9k
R
RT/SYNC
= 15k
TEMPERATURE (°C)
–50
VOLTAGE (V)
2.0
2.5
3.0
25 75
3500 G03
1.5
1.0
–25 0
50 100 150125
0.5
0
MINIMUM INPUT VOLTAGE
SHUTDOWN THRESHOLD
