8

LT1521/LT1521-3

LT1521-3.3/LT1521-5

OUT (Pin 1): The output pin supplies power to the load. A

minimum output capacitor of 1.5

µF is required to prevent

oscillations, but larger values of output capacitor will be

necessary to deal with larger load transients. See the

Applications Information section for more on output

capacitance and reverse output characteristics.

SENSE (Pin 2): For fixed voltage versions of the LT1521

(LT1521-3, LT1521-3.3, LT1521-5), the sense pin is the

input to the error amplifier. Optimum regulation will be

obtained at the point where the sense pin is connected to

LT1521-5

Transient Response

TIME (

µs)

0

0.2

0.1

0

–0.1

–0.2

150

100

50

400

LT1521 • TPC33

100

50

150

250

350

450

200

300

500

FREQUENCY (Hz)

100

90

80

70

60

50

40

30

20

10

0

10

1k

10k

1M

LT1521 • TPC31

100

100k

SOLID TANTALUM

SOLID TANTALUM

Ripple Rejection

Load Regulation

TEMPERATURE (

°C)

–50

25

LT1521 • TPC32

–25

0

50

0

–5

–10

–15

–20

–25

–30

–35

–40

75

100

125

LT1521-3.3

LT1521-3

LT1521*

LT1521-5

LT1521-5

Transient Response

TIME (ms)

0

0.2

0.1

0

–0.1

–0.2

300

200

100

4.0

LT1521 • TPC34

1.0

0.5

1.5

2.5

3.5

4.5

2.0

3.0

5.0

the output pin of the regulator. In critical applications small

between the regulator and the load, which would normally

degrade regulation, may be eliminated by connecting the

sense pin to the output at the load as shown in Figure 1

(Kelvin Sense Connection). Note that the voltage drop

across the external PC traces will add to the dropout

voltage of the regulator. The sense pin bias current is 5

µA

at the nominal regulated output voltage. This pin is inter-