MPQ2169B

– 6V, DUAL 1.4A/1.4A OR 2A/0.8A SYNC BUCK REGULATOR, AEC-Q100

MPQ2169B Rev. 1.0

MonolithicPower.com

22

12/20/2021

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

© 2021 MPS. All Rights Reserved.

The output voltage ripple (

∆VOUT) can be

estimated using Equation (6):

(

)

OUT

IN

OUT

OUT

IN

SW

SW

O

V

V

V

1

V

(ESR

)

V

L f

8 f

C

−



=



+

 





(6)

Power Dissipation

IC power dissipation is important in circuit

design, not only because of efficiency concerns,

but

also

because

of

the

c

hip’s thermal

requirements. Several parameters influence

power dissipation, such as conduction loss

(PCOND), dead time (DT), switching loss (PSW),

MOSFET driver current (PDR), and supply

current (PS).

Based on these parameters, the power loss

(PLOSS) can be calculated using Equation (7):

LOSS

COND

DT

SW

DR

S

P

P

P

P

P

P

=

+

+

+

+

(7)

Thermal Regulation

Changes in IC temperatures can change the

electrical characteristics, especially when the

temperature exceeds

the IC’s recommended

operating

range.

Managing

the

IC’s

temperature requires additional considerations

to ensure that the IC runs within the maximum

allowable temperature junction. Specific layout

designs can improve the thermal profile while

limiting losses to the efficiency and/or operating

range.

For the MPQ2169B, connect the ground pin on

the package to a ground plane on top of the

PCB, and use this plane as a heatsink. Connect

this ground plane to the ground planes beneath

the IC using vias to improve heat dissipation.

Given that these ground planes can introduce

unwanted EMI noise and occupy valuable PCB

space, design their size and shape to match the

thermal resistance requirement.

Connecting the ground pin to a heatsink does

not guarantee that the IC remains within its

recommended

temperature

limits

(e.g.

the

ambient temperature may exceed

the IC’s

temperature

limits).

If

the

ambient

air

temperature approaches the IC’s temperature

limit, the IC can be derated to operate using

less

power,

which

helps

prevent

thermal

damage

and

unwanted

electrical

characteristics.