LT1521/LT1521-3
LT1521-3.3/LT1521-5
The ● denotes the specifications which apply over the full operating
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are at TA = 25°C.
PARAMETER
CONDITIONS
= –20V, V
LT1521-3
LT1521-3.3
LT1521-5
MIN
TYP
MAX
UNITS
Input Reverse Leakage Current
Reverse Output Current (Note 11)
V
IN
= 0V
OUT
●
1.0
mA
V
V
V
V
= 3V, V < 3V, T = 25°C
5
5
5
5
10
10
10
10
µA
µA
µA
µA
OUT
OUT
OUT
OUT
IN
J
= 3.3V, V < 3.3V, T = 25°C
IN
J
= 5V, V < 5V, T = 25°C
IN
J
LT1521 (Note 5)
= 3.8V, V < 3.75V, T = 25°C
IN J
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 5: The LT1521 (adjustable version) is tested and specified with the
adjust pin connected to the output pin.
Note 2: The shutdown pin input voltage rating is required for a low
impedance source. Internal protection devices connected to the shutdown
pin will turn on and clamp the pin to approximately 7V or –0.6V. This
range allows the use of 5V logic devices to drive the pin directly. For high
impedance sources or logic running on supply voltages greater than 5.5V,
the maximum current driven into the shutdown pin must be limited to less
than 5mA.
Note 6: Dropout voltage is the minimum input/output voltage required to
maintain regulation at the specified output current. In dropout the output
voltage will be equal to: (V – V
)
IN
DROPOUT
Note 7: Ground pin current is tested with V = V
(nominal) and a
OUT
IN
current source load. This means the device is tested while operating in its
dropout region. This is the worst-case ground pin current. The ground pin
current will decrease slightly at higher input voltages.
Note 3: For junction temperatures greater than 110°C, a minimum load of
Note 8: Adjust pin bias current flows into the adjust pin.
1mA is recommended. For T > 110°C and I
< 1mA, output voltage
J
OUT
Note 9: Shutdown pin current at V
= 0V flows out of the shutdown
SHDN
may increase by 1%.
pin.
Note 4: Operating conditions are limited by maximum junction
temperature. The regulated output voltage specification will not apply for
all possible combinations of input voltage and output current. When
operating at maximum input voltage, the output current range must be
limited. When operating at maximum output current, the input voltage
range must be limited.
Note 10: Quiescent current in shutdown is equal to the total sum of the
shutdown pin current (2µA) and the ground pin current (4µA).
Note 11: Reverse output current is tested with the input pin grounded and
the output pin forced to the rated output voltage. This current flows into
the output pin and out of the ground pin.
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
Guaranteed Dropout Voltage
Dropout Voltage
Quiescent Current
0.8
15.0
12.5
10.0
7.5
5.0
2.5
0
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
= TEST POINTS
0.7
0.6
V
= OPEN
SHDN
I
= 300mA
T
≤ 125°C
LOAD
J
0.5
0.4
0.3
0.2
0.1
I
= 150mA
LOAD
T
≤ 25°C
I
= 100mA
J
LOAD
V
= 0V
SHDN
I
= 50mA
LOAD
I
V
= 6V
IN
L
R
= ∞
= 1mA
LOAD
I
= 0
LOAD
0
–25
0
50
75 100 125
–50 –25
0
25
50
75
100 125
–50
25
50
100
200
0
250
300
150
TEMPERATURE (°C)
TEMPERATURE (°C)
OUTPUT CURRENT (mA)
LT1521 • TPC02
LT1521 • TPC03
LT1521 • TPC01
1521335fb
4
Linear [ Linear ]
