Datasheet

3
LT1581/LT1581-2.5
ELECTRICAL CHARACTERISTICS
The ● denotes 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
Dropout Voltage (Note 3)
Minimum V
CONTROL
: LT1581-2.5 V
POWER
= 3.3V, I
LOAD
= 100mA ● 1.02 1.25 V
(V
CONTROL
– V
OUT
)V
POWER
= 3.3V, I
LOAD
= 1A ● 1.04 1.27 V
V
POWER
= 3.3V, I
LOAD
= 4A ● 1.06 1.30 V
V
POWER
= 3.3V, I
LOAD
= 7A ● 1.10 1.33 V
V
POWER
= 3.3V, I
LOAD
= 10A ● 1.12 1.35 V
Minimum V
CONTROL
: LT1581 V
POWER
= 2.05V, I
LOAD
= 100mA ● 1.02 1.25 V
(V
CONTROL
– V
OUT
)V
POWER
= 2.05V, I
LOAD
= 1A ● 1.04 1.27 V
(V
ADJ
= 0V) V
POWER
= 2.05V, I
LOAD
= 4A ● 1.06 1.30 V
V
POWER
= 2.05V, I
LOAD
= 7A ● 1.10 1.33 V
V
POWER
= 2.05V, I
LOAD
= 10A ● 1.12 1.35 V
Minimum V
POWER
: LT1581-2.5 V
CONTROL
= 5V, I
LOAD
= 100mA ● 0.10 0.20 V
(V
POWER
– V
OUT
)V
CONTROL
= 5V, I
LOAD
= 1A ● 0.13 0.25 V
V
CONTROL
= 5V, I
LOAD
= 4A, T
J
= 25°C 0.22 0.33 V
V
CONTROL
= 5V, I
LOAD
= 4A ● 0.37 V
V
CONTROL
= 5V, I
LOAD
= 7A, T
J
= 25°C 0.31 0.45 V
V
CONTROL
= 5V, I
LOAD
= 7A ● 0.55 V
V
CONTROL
= 5V, I
LOAD
= 10A, T
J
= 25°C 0.43 0.63 V
V
CONTROL
= 5V, I
LOAD
= 10A ● 0.70 V
Minimum V
POWER
: LT1581 V
CONTROL
= 2.75V, I
LOAD
= 100mA ● 0.10 0.20 V
(V
POWER
– V
OUT
)V
CONTROL
= 2.75V, I
LOAD
= 1A ● 0.13 0.25 V
(V
ADJ
= 0V) V
CONTROL
= 2.75V, I
LOAD
= 4A, T
J
= 25°C 0.22 0.33 V
V
CONTROL
= 2.75V, I
LOAD
= 4A ● 0.37 V
V
CONTROL
= 2.75V, I
LOAD
= 7A, T
J
= 25°C 0.31 0.45 V
V
CONTROL
= 2.75V, I
LOAD
= 7A ● 0.55 V
V
CONTROL
= 2.75V, I
LOAD
= 10A, T
J
= 25°C 0.43 0.63 V
V
CONTROL
= 2.75V, I
LOAD
= 10A ● 0.70 V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Unless otherwise specified, V
OUT
= V
SENSE
. For the LT1581
adjustable device, V
ADJ
= 0V.
Note 3: For the LT1581, dropout is caused by either minimum control
voltage (V
CONTROL
) or minimum power voltage (V
POWER
). Both parameters
are specified with respect to the output voltage. The specifications represent
the minimum input-to-output voltage required to maintain 1% regulation.
Note 4: For the LT1581 adjustable device the minimum load current is the
minimum current required to maintain regulation. Normally, the current in
the resistor divider used to set the output voltage is selected to meet the
minimum load current requirement.
Note 5: The CONTROL pin current is the drive current required for the
output transistor. This current will track output current with roughly a
1:100 ratio. The minimum value is equal to the quiescent current of the
device.