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

Rev1.0 Jan.10, 2020

AX3601

28VIN 5A Synchronous 4-Switch Buck-Boost Converter

GENERAL DESCRIPTION

The AX3601 is a wide input range fully integrated 4-switch synchronous buck-boost

converter capable of regulating the output voltage at, above, or below the input voltage. The

device employs the patented peak current mode with constant off-time control scheme that

significantly simplifies control loop design and offers seamless transition between Buck,

Buck-boost and Boost mode operations. Proprietary inductor DCR current sensing

eliminates the need of external current sense resistor and improves system power efficiency.

With external compensation, the AX3601 can be optimized to operate with a wide range of

input and output voltage at all current level. The AX3601 comes with internal soft-start,

programmable inductor peak current limit, input under-voltage and over-voltage lockout,

hiccup mode for short circuit or overload protection and thermal shutdown. The high

integration level of the AX3601 offers great ease of use and minimizes the external

components as well as board space, The AX3601 is available with a small footprint

5mmx5mm 28-lead TQFN package.

FEATURES

- Input Voltage Range from 4V to 28V

- Output Voltage Range from 1V to 28V

- Integrated Four 12mΩ Power Switches with 20A Peak Current Capability

- Up to 5A Output Current

- Up to 97.5% Efficiency

- Inductor DCR Current Sensing

- Programmable Input Switch Current Limit

- Accurate EN Threshold Voltage

- 500kHz Switching Frequency

- Output Voltage Power Good Indicator

- Cycle-by-Cycle Peak Current Limit

- Short Circuit Protection with Hiccup Mode

- Thermal Shutdown

- Available in 5mmx5mm 28-Lead TQFN Package

- Pb-Free ROHS compliant

- RoHS and Halogen free compliance

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

Rev1.0 Jan.10, 2020

AX3601

APPLICATION

- USB Type C Hub

- 5V,9V,12V,20V and 24 VDC Bus Power

- Power Banks and Electronic Cigarette

- USB-PD and Thunderbolt Ports for PCs

- Tablet Computer Accessories

- Industrial Battery Powered Systems

Functional Block Diagram

FB

SW1

V100

VREFSS

VREFSS E

A

EN

AGND

Soft-Start

VIN

VOUT

Current Sense

COMP

CSP

CSN

Constant

Off-time

COMP

VIN

VOUT

BKTOFF

BSTOFF

VIN

VOUT

VIN

VOUT

INBCK

INBB

INBST

INBCK

INBB

INBST

BKTOFF

BSTOFF

COMP

BCKHSON

BCKLSON

BSTHSON

BSTLSON

Control Logic

Driver

BS

T1

BS

T2

HS1DR

HS2DR

LS1DR

LS2DR

SW1

SW2

SW2

PGND

BST1 BST2

ILIM OVLD

ILIM

INBCK

INBB

INBST

HICCP

VFB

V090

PG

OUTMode

Control

VIN

VOUT

VCC

regulator

VCC

Current

Limit

SW1 SW2

IN

HS1

LS1

LS2

HS2

PCOMP

VCTRL

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

Rev1.0 Jan.10, 2020

AX3601

Typical Application

CSP

VIN

4V~28V

CSN

EN

OUT

SW2COMP

BST2

FB

VCC

Cs 2.2nF Rs 5.1K

Cp 100pF

R2 1K

R4

20K

VOUT

5V/5A

CIN2

22μFx3

L

2.2μH

CBS2 220nF

COUT2

22μFx4

AX3601

CEN

0.1μF

C1 4.7μF

R1 10K

REN

100k

GND

PGND

CFF

100pF

R3

80.6K

ILIM

SW1

BST1VIN

COUT1

0.1μF

CIN1

0.1μFCBS1 220nF

C2

22nF

C3

10nF

C4

10nF

PIN ASSIGNMENT The package of AX3601 is TQFN5*5-28L the pin assignment is given by:

SW2

SW2

BST2

BST1

SW1

SW1

PG

ND

PG

ND

PG

ND

IN IN IN

VC

C

PG

ND

AGND

COMP

ILIM

FB

EN

CSN

CS

P

PG

OU

T

OU

T

OU

T

PG

ND

PG

ND

PG

ND

1

2

3

4

5

6

7 8 9 10 11 12 13 14

15

16

17

18

19

20

2122232425262728

PGND