Datasheet

LT3055
4
3055f
For more information www.linear.com/LT3055
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Current Monitor Ratio (Notes 6,10), Ratio = I
OUT
/I
MON
I
LOAD
= 10mA, 250mA, 500mA
l
450 500 550 mA/mA
TEMP Voltage (Note 16) T
J
= 25°C
T
J
= 125°C
0.25
1.25
V
V
TEMP Error (Note 16)
l
–0.08 0.08 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. Absolute maximum input-to-output differential
voltage is not achievable with all combinations of rated IN pin and OUT pin
voltages. With the IN pin at 50V, the OUT pin may not be pulled below 0V.
The total differential voltage from IN to OUT must not exceed +50V, –40V.
If OUT is pulled above GND and IN, the total differential voltage from OUT
to IN must not exceed 40V.
Note 2: The LT3055 is tested and specified under pulse load conditions
such that T
J
~ T
A
. The LT3055E is 100% production tested at T
A
= 25°C
and performance is guaranteed from 0°C to 125°C. Performance at –40°C
and 125°C is assured by design, characterization and correlation with
statistical process controls. The LT3055I is guaranteed over the full –40°C
to 125°C operating junction temperature range. The LT3055MP is 100%
tested over the –55°C to 150°C operating junction temperature range. The
LT3055H is 100% tested at 150°C operating junction temperature.
Note 3: The LT3055 adjustable version is tested and specified for these
conditions with ADJ pin connected to the OUT pin.
Note 4: Maximum junction temperature limits operating conditions.
Regulated output voltage specifications do not apply for all possible
combinations of input voltage and output current. If operating at the
maximum input voltage, limit the output current range. If operating at
the maximum output current, limit the input voltage range. Current limit
foldback limits the maximum output current as a function of input-to-
output voltage. See Current Limit vs V
IN
-V
OUT
in the Typical Performance
Characteristics section.
Note 5: Dropout voltage is the minimum differential IN-to-OUT voltage
needed to maintain regulation at a specified output current. In dropout,
the output voltage equals (V
IN
– V
DROPOUT
). For some output voltages,
minimum input voltage requirements limit dropout voltage.
Note 6: To satisfy minimum input voltage requirements, the LT3055
adjustable version is tested and specified for these conditions with an
external resistor divider (60k bottom, 440k top) which sets V
OUT
to 5V. The
external resistor divider adds 10μA of DC load on the output. This external
current is not factored into GND pin current.
Note 7: GND pin current is tested with V
IN
= V
OUT(NOMINAL)
+ 0.6V and a
current source load. GND pin current increases in dropout. See GND pin
current curves in the Typical Performance Characteristics section.
Note 8: Current limit varies inversely with the external resistor value tied
from the I
MAX
pin to GND. For detailed information on how to set the I
MAX
pin resistor value, please see the Operation section. If a programmed
current limit is not needed, tie the I
MAX
pin to GND and internal protection
circuitry implements short-circuit protection as specified.
Note 9: The I
MIN
fault condition asserts if the output current falls below the
I
MIN
threshold defined by an external resistor from the I
MIN
pin to GND.
For detailed information on how to set the I
MIN
pin resistor value, please
see the Operation section. If the I
MIN
fault condition is not needed, the I
MIN
pin must be left floating (unconnected).
Note 10: Current monitor ratio is tested with the I
MON
pin fixed at
V
OUT
– 0.5V and with the input range limited to V
OUT
+ 0.6V < V
IN
< V
OUT
+ 10V for I
OUT
= 10mA; V
OUT
+ 0.6V < V
IN
< V
OUT
+ 4V for I
OUT
= 250mA,
and V
OUT
+ 0.6V < V
IN
< V
OUT
+ 2V for I
OUT
= 500mA. Input voltage range
conditions are set to limit power dissipation in the IC to 1W maximum for
test purposes. The current monitor ratio varies slightly when in current
limit or when the I
MON
voltage exceeds V
OUT
– 0.5V. Please see the
Operation section for more information. If the current monitor function is
not needed, tie the IMON pin to GND.
Note 11: To satisfy requirements for minimum input voltage, current limit
is tested at V
IN
= V
OUT(NOMINAL)
+ 1V or V
IN
= 2.2V, whichever is greater.
Note 12: ADJ pin bias current flows out of the ADJ pin.
Note 13: SHDN pin current flows into the SHDN pin.
Note 14: Reverse output current is tested with the IN pin grounded and the
OUT pin forced to the specified voltage. This current flows into the OUT
pin and out of the GND pin.
Note 15: 500mA of output current does not apply to the full range of input
voltage due to the internal current limit foldback.
Note 16: The TEMP output voltage represents the average temperature of
the die while dissipating quiescent power. Due to the pass device power
dissipation and temperature gradients across the die, the TEMP output
voltage measurement does not guarantee that absolute maximum junction
temperature is not exceeded.