NB679A

–28V VIN, FIXED 5.1V-8A BUCK CONVERTER WITH LDO AND LP# VOUT SCALING

NB679A 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 = 12V, TJ = 25C, unless otherwise noted.

Parameters

Symbol

Condition

Min

Typ

Max

Units

Supply Current

Supply current (shutdown)

IIN

VEN = 0V, VLP# = 0V,

1

2

μA

Supply current (quiescent)

IIN

VEN = VLP# = 3.3V,

VOUT = 5.5V

110

130

µA

MOSFET

High-side switch on resistance

HSRDS-ON

25

mΩ

Low-side switch on resistance

LSRDS-ON

12

mΩ

Switch leakage

SWLKG

VEN = 0V, VSW = 0V

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 = 9.7V, VLP# = 0V

600

710

820

ns

Minimum on time

(5)

TON_Min

50

ns

Minimum off time

(5)

TOFF_Min

200

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

(5)

TUVP-1

32

µs

UVP-2 threshold

VUVP-2

45%

50%

55%

VREF

Reference and Soft Start

Vout REF voltage

VOUT_REF

VLP# = 3.3V

5.05

5.1

5.15

V

VLP# = 0V

4.8

4.85

4.9

Soft-start time

TSS

EN to Vout OK

1.7

2.5

ms

Enable and UVLO

Enable rising threshold

VEN_H

1.2

1.3

1.4

V

Enable hysteresis

VEN-HYS

150

mV

EN high limit @ USM

VEN_H_USM

1.8

V

EN low limit @ Normal

VEN_L_Normal

2.6

V

Enable input current

IEN

VEN = 2V

5

μA

VEN = 0V

0

VIN under-voltage lockout

threshold rising

VINVTH

4.45

4.7

V