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AS1334

Datasheet - A p p l i c a t i o n I n f o r m a t i o n

9 Application Information

Inductor Selection

For the external inductor, a 3.3µH inductor is recommended. Minimum inductor size is dependant on the desired effi-

ciency and output current. Inductors with low core losses and small DCR at 2MHz are recommended.

Capacitor Selection

recommended as they retain capacitance over wide ranges of voltages and temperatures.

Input and Output Capacitor Selection

Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. Also low

have extremely low ESR and are available in small footprints.

For input decoupling the ceramic capacitor should be located as close to the device as practical. A 4.7µF input capaci-

tor is sufficient for most applications. Larger values may be used without limitations.

A 2.2µF to 10µF output ceramic capacitor is sufficient for most applications. Larger values up to 22µF may be used to

obtain extremely low output voltage ripple and improve transient response.

EN Pin Control

Drive the EN pin using the system controller to turn the AS1334 ON and OFF. Use a comparator, Schmidt trigger or

logic gate to drive the EN pin. Set EN high (>1.2V) for normal operation and low (<0.5V) for a 0.01µA (typ.) shutdown

mode. Set EN low to turn off the AS1334 during power-up and under voltage conditions when the power supply is less

than the 2.7V minimum operating voltage. The part is out of regulation when the input voltage is less than 2.7V.

Table 5. Recommended Inductor

Part Number

L

DCR

Current Rating Dimensions (L/W/T)

Manufacturer

LPS4018-222ML_

2.2µH

0.070Ω

2.9A

3.9x3.9x1.7mm

Coilcraft

www.coilcraft.com

LPS4018-332ML_

3.3µH

0.080Ω

2.4A

3.9x3.9x1.7mm

LPS4018-472ML_

4.7µH

0.125Ω

1.9A

3.9x3.9x1.7mm

Table 6. Recommended Input and Output Capacitor

Part Number

C

TC Code

Rated Voltage

Dimensions (L/W/T)

Manufacturer

GRM188R60J475KE19

4.7µF

X5R

6.3V

0603

Murata

www.murata.com

GRM219R60J475KE19

4.7µF

X5R

6.3V

0805

GRM21BR61C475KA88

4.7µF

X5R

16V

0805

GRM31CR71E475KA88

4.7µF

X7R

25V

1206

GRM188R60J106ME47

10µF

X5R

6.3V

0603

GRM21BR60J106KE19

10µF

X5R

6.3V

0805

GRM21BR61A106KE19

10µF

X5R

10V

0805

GRM32DR71C106KA01

10µF

X7R

16V

1210

GRM21BR60J226ME39

22µF

X5R

6.3V

0805

GRM32ER71A226KE20

22µF

X7R

10V

1210