Datasheet

3
LT1083/LT1084/LT1085
108345fe
PARAMETER CONDITIONS MIN TYP MAX UNITS
Load Regulation (V
IN
– V
OUT
) = 3V
10mA ≤ I
OUT
≤ I
FULL LOAD
T
J
= 25°C (Notes 2, 3, 4, 6) 0.1 0.3 %
● 0.2 0.4 %
Dropout Voltage ∆V
REF
= 1%, I
OUT
= I
FULLLOAD
(Notes 5, 6, 8) ● 1.3 1.5 V
Current Limit
LT1083 (V
IN
– V
OUT
) = 5V ● 8.0 9.5 A
(V
IN
– V
OUT
) = 25V ● 0.4 1.0 A
LT1084 (V
IN
– V
OUT
) = 5V ● 5.5 6.5 A
(V
IN
– V
OUT
) = 25V ● 0.3 0.6 A
LT1085 (V
IN
– V
OUT
) = 5V ● 3.2 4.0 A
(V
IN
– V
OUT
) = 25V ● 0.2 0.5 A
Minimum Load Current (V
IN
– V
OUT
) = 25V ● 510 mA
Thermal Regulation T
A
= 25°C, 30ms Pulse
LT1083 0.002 0.010 %/W
LT1084 0.003 0.015 %/W
LT1085 0.004 0.020 %/W
Ripple Rejection f = 120Hz, C
ADJ
= 25µF, C
OUT
= 25µF Tantalum
I
OUT
= I
FULL LOAD
, (V
IN
– V
OUT
) = 3V (Notes 6, 7, 8) ● 60 75 dB
Adjust Pin Current T
J
= 25°C55µA
● 120 µA
Adjust Pin Current Change 10mA ≤ I
OUT
≤ I
FULL LOAD
1.5V ≤ (V
IN
– V
OUT
) ≤ 25V (Note 6) ● 0.2 5 µA
Temperature Stability ● 0.5 %
Long Term Stability T
A
= 125°C, 1000 Hrs 0.3 1 %
RMS Output Noise (% of V
OUT
)T
A
= 25°C
10Hz = ≤ f ≤ 10kHz 0.003 %
Thermal Resistance Junction-to-Case Control Circuitry/Power Transistor
LT1083 K Package 0.6/1.6 °C/W
P Package 0.5/1.6 °C/W
LT1084 K Package 0.75/2.3 °C/W
P Package 0.65/2.3 °C/W
T Package 0.65/2.7 °C/W
LT1085 K Package 0.9/3.0 °C/W
M, T Packages 0.7/3.0 °C/W
ELECTRICAL CHARACTERISTICS
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: See thermal regulation specifications for changes in output voltage
due to heating effects. Load and line regulation are measured at a constant
junction temperature by low duty cycle pulse testing.
Note 3: Line and load regulation are guaranteed up to the maximum power
dissapation (60W for the LT1083, 45W for the LT1084 (K, P), 30W for the
LT1084 (T) and 30W for the LT1085). Power dissipation is determined by
the input/output differential and the output current. Guaranteed maximum
power dissipation will not be available over the full input/output voltage
range.
Note 4: I
FULL LOAD
is defined in the current limit curves. The I
FULLLOAD
curve is defined as the minimum value of current limit as a function of
input-to-output voltage. Note that the 60W power dissipation for the
LT1083 (45W for the LT1084 (K, P), 30W for the LT1084 (T), 30W for the
LT1085) is only achievable over a limited range of input-to-output voltage.
Note 5: Dropout voltage is specified over the full output current range of
the device. Test points and limits are shown on the Dropout Voltage
curve.
Note 6: For LT1083 I
FULL LOAD
is 5A for –55°C ≤ T
J
< – 40°C and 7.5A for
T
J
≥ –40°C.
Note 7: 1.7V ≤ (V
IN
– V
OUT
) ≤ 25V for LT1084 at – 55°C ≤ T
J
≤ –40°C.
Note 8: Dropout is 1.7V maximum for LT1084 at –55°C ≤ T
J
≤ –40°C.
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C.