NB679

— 28V VIN, FIXED 5V-8A BUCK CONVERTER WITH LDO

NB679 Rev. 1.03

www.MonolithicPower.com

4

7/27/2017

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

© 2017 MPS. All Rights Reserved.

ELECTRICAL CHARACTERISTICS

VIN = 12 V, TJ = 25C, unless otherwise noted.

Parameters

Symbol

Condition

Min

Typ

Max

Units

Supply current

Supply current (shutdown)

IIN

VEN = 0 V, VENLDO = 0 V,

1

2

μA

Supply current (quiescent)

IIN

VEN = VENLDO = 3.3 V,

VOUT = 5.5 V

110

130

µA

Supply current (standby)

IIN

VEN = 0 V, VENLDO = 3.3 V,

ILDO = 0 A

60

80

μA

MOSFET

High-side switch on resistance

HSRDS-ON

25

mΩ

Low-side switch on resistance

LSRDS-ON

12

mΩ

Switch leakage

SWLKG

VEN = 0 V, VSW = 0 V

0

1

μA

Current limit

Low-side valley current limit

ILIMIT

10

11

12

A

Switching frequency and timer

Switching frequency

FS

700

kHz

Constant on timer

Ton

Vin = 10 V

600

710

820

ns

Minimum on time

(6)

TON_Min

50

ns

Minimum off time

(6)

TOFF_Min

220

ns

Ultrasonic mode

Ultrasonic mode operation period

TUSM

20

30

40

µs

Over-voltage and under-voltage protection

OVP threshold

VOVP

117%

122%

127%

VREF

UVP-1 threshold

VUVP-1

70%

75%

80%

VREF

UVP-1 foldback timer

(6)

TUVP-1

32

µs

UVP-2 threshold

VUVP-2

45%

50%

55%

VREF

Reference and soft start

Vout REF voltage

VOUT_REF

4.95

5

5.05

V

Soft-start time

TSS

EN to Vout OK

1.7

2.5

ms