Low Dropout Linear Regulator

ADP3309

Rev. C

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FEATURES

±1.2% accuracy over line and load regulations @ 25°C

Ultralow dropout voltage: 120 mV typical @ 100 mA

anyCAP LDOs are stable with all types of capacitors

(including MLCC)

Current and thermal limiting

Low noise

Low shutdown current: 1 μA

2.8 V to 12 V supply range

−20°C to +85°C ambient temperature range

Several fixed voltage options

Ultrasmall 5-lead SOT-23 package

Excellent line and load regulations

APPLICATIONS

Cellular telephones

Notebook, palmtop computers

Battery-powered systems

PCMCIA regulator

Bar code scanners

Camcorders, cameras

FUNCTIONAL BLOCK DIAGRAM

Q1

Q2

THERMAL

PROTECTION

DRIVER

ADP3309

CC

BANDGAP

REF

GND

R1

R2

OUT

IN

ERR/NC

SD

Figure 1.

GENERAL DESCRIPTION

The ADP3309 is a member of the ADP330x family of precision

low dropout anyCAP voltage regulators. It is pin-for-pin and

functionally compatible with National’s LP2981, but offers

performance advantages. The ADP3309 stands out from

conventional LDOs with a novel architecture and an enhanced

process. Its patented design requires only a 0.47 μF output

capacitor for stability. This device is stable with any type of

capacitor regardless of its equivalent series resistance (ESR)

value, including ceramic types for space restricted applications.

The ADP3309 achieves ±1.2% accuracy at room temperature

and ±2.2% overall accuracy over temperature, line, and load

regulations. The dropout voltage of the ADP3309 is only

120 mV (typical) at 100 mA. This device also includes a current

limit and a shutdown feature. In shutdown mode, the ground

current is reduced to ~1 μA.

The ADP3309 operates with a wide input voltage range from

2.8 V to 12 V and delivers a load current in excess of 100 mA.

The ADP3309 anyCAP LDO offers a wide range of output

voltages.

+

–

+

–

ADP3309-3.3

IN

OUT

GND

ERR/NC

SD

ON

OFF

C2

0.47µF

C1

0.47µF

4

5

3

2

1

Figure 2. Typical Application Circuit