dissipated due to the RMS current through the internal

in the package must be limited such that the junction

temperature does not exceed its absolute maximum rating

of +150°C at maximum ambient temperature. Calculate

the power lost in the MAX15014–MAX15017 using the

following equations:

The power loss through the switch:

MOSFET

RMS_MOSFET

ON

22

RMS_MOSFET

PK

PK

DC

DC

PP

PK

OUT

PP

DC

OUT

OUT

IN

2

P

(I

) R

D

I

I

(I

I

) I

3

I

II

2

I

II

2

V

D

V

−

−

=

×





=

×

+

×

+









∆

=

+

∆

=

−

=

(see the Electrical Characteristics).

The power loss due to switching the internal MOSFET:

IN OUT

R

F

SW

SW

V

I

(t

t ) f

P

4

×

×

+×

=

MOSFET measured at LX.

The power loss due to the LDO regulator:

The total power dissipated in the device will be:

Figure 6. MAX15015/MAX15016 Typical Application Circuit (4.5V to 40V Input Operation)

MAX15015

MAX15016

SGND

SGND

SET_LDO

0.47µF

1Ω

PGND

PGND

R5

C7

DVREG

R4

R3

C-

C+

FB

COMP

EN_SYS

EN_SW

REG

SYNC

SS

R6

C6

CT

5V TO 40V

RESET

LDO_OUT

D2

10kΩ

LX

BST

L

IN_SW

DRAIN

D1

IN_LDO

C8

4.5V TO 40V

MAX15014–MAX15017

1A, 4.5V to 40V Input Buck Converters with

50mA Auxiliary LDO Regulators

www.maximintegrated.com

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