Datasheet

4
LT1581/LT1581-2.5
TYPICAL PERFORMANCE CHARACTERISTICS
UW
PIN FUNCTIONS
UUU
OUTPUT CURRENT (A)
0
MINIMUM CONTROL VOLTAGE
(V
CONTROL
– V
OUT
) (V)
2






0
1
5
7
1581 G02
4
2
3
68
10
9
1
INDICATES GUARANTEED TEST POINTS
DATA SHEET LIMIT
T
J
= 25°CT
J
= 125°C
TEMPERATURE (°C)
–50 –25
OUTPUT VOLTAGE (V)
150
1581 G05
0 25 75 125
50
100
2.512
2.509
2.506
2.503
2.500
2.497
2.494
2.491
2.488
TEMPERATURE (°C)
–50 –25
REFERENCE VOLTAGE (V)
150
1581 G04
0 25 75 125
50
100
1.262
1.259
1.256
1.253
1.250
1.247
1.244
1.241
1.238
LT1581 Reference Voltage vs
Temperature
Control Pin Current vs
Output Current
400mA
LT1581-2.5 Output Voltage vs
Temperature
V
OUT
50mV/DIV
50µs/DIV 1581 G06
Load Current Step Response
ADJUST (Pin 1): This pin is the negative side of the
reference voltage for the device. Transient response can
be improved by adding a small bypass capacitor from the
ADJUST pin to ground. For fixed voltage devices the
ADJUST pin is also brought out to allow the user to add a
bypass capacitor.
GND (Pin 2, Fixed Voltage Devices Only): For fixed
voltage devices this is the bottom of the resistor divider
that sets the output voltage.
SENSE (Pin 3): This pin is the positive side of the reference
voltage for the device. With this pin it is possible to Kelvin
sense the output voltage at the load.
OUTPUT (Pin 4): This is the power output of the device.
V
POWER
(Pin 5): This is the collector to the power device
of the LT1581. The output load current is supplied through
this pin. For the device to regulate, the voltage at this pin
must be between 0.1V and 0.7V greater than the output
voltage (see Dropout specifications).
V
CONTROL
(Pin 6): This pin is the supply pin for the control
circuitry of the device. The current flow into this pin will
be about 1% of the output current. For the device to
regulate, the voltage at this pin must be between 1.0V and
1.35V greater than the output voltage (see Dropout
specifications).
Dropout Voltage —
Minimum Control Voltage
10A
LOAD
OUTPUT CURRENT (A)
MINIMUM POWER VOLTAGE (V)
(V
POWER
– V
OUT
) (V)
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1581 G03
0
1
5
7
4
2
3
68
10
9
DATA SHEET LIMIT
T
J
= 25°C
T
J
= 125°C
INDICATES GUARANTEED TEST POINTS
Dropout Voltage —
Minimum Power Voltage
OUTPUT CURRENT (A)
0

200
180
160
140
120
100
80
60
40
20
0
35
1581 G01
12
467
8
910
CONTROL PIN CURRENT (mA)
DATA SHEET LIMIT
INDICATES GUARANTEED TEST POINTS
TYPICAL
DEVICE

