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Axelite Confidential Materials, do not copy or distribute without written consent.

Rev.1.5 Oct.16, 2019

AX3121

Internal NMOS RDSON (Note1)

RDS(ON)-N

-

75 140

mΩ

-

45 120

Thermal Shutdown

TSD

-

150

-

°C

Thermal Shutdown Hysteresis

TSH

-

30

-

°C

Note1: Guaranteed by design.



APPLICATION CIRCUIT

1. Using Aluminum Electrolytic Capacitor (AL)

C1

470uF

C4

470uF

1

2

L1

33uH

R2

13K

R5

3K

VIN=4.5~20V

VOUT = 3.3V/3.5A

R4

C5

0.1uF

FB

2

EN/SS

3

COMP

1

PVcc

4

SVcc

8

SW

6

PGND

7

SGND

5

AX3121ES

R2

R5

VFB = 0.62V ; R5 suggest 3K ~ 6.8k

VOUT = VFB x (1 +

)

C2

0.1uF

C7

4.7nF

C9

C6

0.1uF

C3

R6

3R3

COUT ESR Range

VIN

VOUT

R4(Ω)

C9

C3

30m~80mΩ

4.5V~20V

1.2~5V

1.2K

10n

1000p

80m~300mΩ

4.5V~20V

1.2~1.8V

240

10n

22p

4.5V~20V

2.0~5V

240

10n

180p~270p

2. Using Multilayer Ceramic Capacitor (MLCC)

C1

10uF*2

C4

22uF*2

1

2

L1

33uH

R2

13K

R5

3K

VIN=4.5~20V

VOUT = 3.3V/3.5A

R4

C5

0.1uF

FB

2

EN/SS

3

COMP

1

PVcc

4

SVcc

8

SW

6

PGND

7

SGND

5

AX3121

R1

R5

VFB = 0.62V ; R5 suggest 3K ~ 6.8k

VOUT = VFB x (1 +

)

C2

0.1uF

C7

4.7nF

C8

C6

0.1uF

C3

R6

3R3

4K7 1000p

1000p

VIN

VOUT

R4

C8

C3

4.5V~20V

2.0V~5V

4K7

1000p

1000p