Datasheet

LT3090
4
3090fa
For more information www.linear.com/LT3090
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 LT3090 is tested and specified under pulsed load conditions
such that T
J
≅ T
A
. The LT3090E is guaranteed to meet performance
specifications from 0°C to 125°C junction temperature. Specifications over
the –40°C to 125°C operating temperature range are assured by design,
characterization, and correlation with statistical process controls. The
LT3090I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The LT3090MP is 100% tested and guaranteed
over the full –55°C to 150°C operating junction temperature range. The
LT3090H is 100% tested at the 150°C operating junction temperature.
High junction temperatures degrade operating lifetimes. Operating lifetime
is derated at junction temperatures greater than 125°C.
Note 3. Parasitic diodes exist internally between the OUT, SET, ILIM,
SHDN, IMONP, IMONN, and GND pins and the IN pin. Do not drive OUT,
SET, ILIM, SHDN, IMONP, IMONN, and GND pins more than 0.3V below
the IN pin during fault conditions. These pins must remain at a voltage
more positive than IN during
normal operation.
Note 4.
The LT3090 may go out of regulation if the minimum output
current requirement is not satisfied.
Note 5. Maximum junction temperature limits operating conditions. The
regulated output voltage specification does not apply for all possible
combinations of input voltage and output current, primarily due to the
internal current limit foldback which decreases current limit at V
OUT
– V
IN
≥ 7V. If operating at maximum output current, limit the input voltage
range. If operating at maximum input voltage, limit the output current
range.
Note 6. Load regulation is Kelvin sensed at the package.
Note 7. Dropout voltage is the minimum output-to-input voltage
differential needed to maintain regulation at a specified output current. In
dropout, the output voltage is: V
IN
+ V
DROPOUT
.
Note 8. GND pin current is tested with V
IN
= V
OUT(NOMINAL)
and a current
source load. Therefore, the device is tested while operating in dropout.
This is the worst-case GND pin current. GND pin current decreases at
higher input voltages.
Note 9. The SET pin is clamped to OUT with diodes through 12k resistors.
These resistors and diodes only carry current under transient overloads or
fault conditions.
Note 10. Positive SHDN pin current flows into
the SHDN pin.
Note 11. The SHDN threshold must be met to ensure device operation.
Note 12. Output noise decreases by adding a capacitor across the voltage
setting resistor. Adding this capacitor bypasses the voltage setting
resistor’s thermal noise as well as the reference current’s noise. Output
noise then equals the error amplifier noise (see Applications Information
section).
Note 13. The internal back-up current limit circuitry incorporates foldback
protection that decreases current limit for V
OUT
– V
IN
≥ 7V. Some level of
output current is provided at all V
OUT
– V
IN
differential voltages. Please
consult the Typical Performance Characteristic graph for current limit vs
V
OUT
– V
IN
.
Note 14. The current limit programming scale factor is specified while
the internal backup current limit is not active. Please note that the internal
current limit has foldback protection for V
OUT
-to-V
IN
differentials greater
than 7V.
Note 15. For positive current monitoring, bias IMONN to ≥ 2V above
IMONP.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Positive Current Monitor
(Note 15)
Positive Current Monitoring (IMONP) Scale Factor
I
OUT
= 600mA, V
IN
= –2.5V, V
IMONN
= 2V, V
IMONP
= 0V
I
OUT
= 100mA, V
IN
= –2.5V, V
IMONN
= 2V, V
IMONP
= 0V
l
l
280
42.5
0.5
300
50
320
57.5
mA/A
µA
µA
Negative Current Monitor
Negative Current Monitoring (IMONN) Scale Factor
I
OUT
= 600mA, V
IN
= –2.5V, V
IMONN
= 0V, V
IMONP
= –2.5V
I
OUT
= 100mA, V
IN
= –2.5V, V
IMONN
= 0V, V
IMONP
= –2.5V
l
l
560
85
1
600
100
640
115
mA/A
µA
µA
Minimum Required Load
Current (Note 4)
–36V < V
IN
< –1.9V
l
10 µA
Thermal Regulation ISET 10ms Pulse 0.04 %/W
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.
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