LT1521/LT1521-3

LT1521-3.3/LT1521-5

4

Rev. C

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ELECTRICAL CHARACTERISTICS The

l

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Ground Pin Current (Note 7)

ILOAD = 0mA

l

12

25

µA

ILOAD = 1mA

l

65

100

µA

ILOAD = 10mA

l

300

450

µA

ILOAD = 50mA

l

0.8

1.5

mA

ILOAD = 100mA

l

1.4

2.5

mA

ILOAD = 150mA

l

2.2

4.0

mA

ILOAD = 300mA

l

6.5

12.0

mA

Adjust Pin Bias Current (Notes 5, 8)

TJ = 25°C

50

100

nA

Shutdown Threshold

VOUT = Off to On

VOUT = On to Off

l

l

0.25

1.20

0.75

2.80

V

V

Shutdown Pin Current (Note 9)

VSHDN = 0V

l

2.0

5.0

µA

Quiescent Current in Shutdown (Note 10) VIN = VOUT (NOMINAL) + 1V, VSHDN = 0V

l

6

12

µA

Ripple Rejection

VIN – VOUT = 1V(Avg), VRIPPLE = 0.5VP–P,

fRIPPLE = 120Hz, ILOAD = 150mA

50

58

dB

Current Limit

VIN – VOUT = 7V, TJ = 25°C

VIN = VOUT (NOMINAL) + 1.5V, ∆VOUT = –0.1V

l

320

400

400

800

mA

mA

Input Reverse Leakage Current

VIN = –20V, VOUT = 0V

l

1.0

mA

Reverse Output Current (Note 11)

LT1521-3

VOUT = 3V, VIN < 3V, TJ = 25°C

LT1521-3.3

VOUT = 3.3V, VIN < 3.3V, TJ = 25°C

LT1521-5

VOUT = 5V, VIN < 5V, TJ = 25°C

LT1521 (Note 5)

VOUT = 3.8V, VIN < 3.75V, TJ = 25°C

5

5

5

5

10

10

10

10

µA

µA

µA

µA

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.

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 3: For junction temperatures greater than 110°C, a minimum load

of 1mA is recommended. For TJ > 110°C and IOUT < 1mA, output voltage

may increase by 1%.

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 5: The LT1521 (adjustable version) is tested and specified with the

adjust pin connected to the output pin.

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: (VIN – VDROPOUT).

Note 7: Ground pin current is tested with VIN = VOUT (nominal) and a

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 8: Adjust pin bias current flows into the adjust pin.

Note 9: Shutdown pin current at VSHDN = 0V flows out of the shutdown

pin.

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.