3

LT1121/LT1121-3.3/LT1121-5

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Load Regulation

LT1121-3.3

– 20

mV

q

–20

– 30

mV

LT1121-5

– 30

mV

q

–28

– 45

mV

LT1121 (Note 4)

– 20

mV

q

–18

– 30

mV

Dropout Voltage

0.13

0.16

V

(Note 5)

q

0.25

V

0.30

0.35

V

q

0.50

V

0.37

0.45

V

q

0.60

V

0.42

0.55

V

q

0.70

V

Ground Pin Current

q

30

50

µA

(Note 6)

q

90

120

µA

q

350

500

µA

q

1.5

2.5

mA

q

4.0

7.0

mA

q

7.0

14.0

mA

Adjust Pin Bias Current (Notes 4, 7)

150

300

nA

Shutdown Threshold

q

1.2

2.8

V

q

0.25

0.75

V

Shutdown Pin Current (Note 8)

q

610

µA

Quiescent Current in Shutdown (Note 9)

q

15

22

µA

Ripple Rejection

58

dB

Current Limit

200

500

mA

Input Reverse Leakage Current

q

1.0

mA

Reverse Output Current (Note 10)

LT1121-3.3

16

25

µA

LT1121-5

16

25

µA

LT1121 (Note 4)

16

25

µA

ELECTRICAL C

C

HARA TERISTICS

Note 4: The LT1121 (adjustable version) is tested and specified with the

adjust pin connected to the output pin.

Note 5: Dropout voltage is the minimum input/output voltage required to

maintain regulation at the specified output current. In dropout the output

current source load. This means that 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 7: Adjust pin bias current flows into the adjust pin.

Note 9: Quiescent current in shutdown is equal to the sum total of the

shutdown pin current (6

µA) and the ground pin current (9µA).

Note 10: 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.

range.

Note 1: 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 20mA.

Note 2: For junction temperatures greater than 110

°C, a minimum load of

may increase by 1%.

Note 3: 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.