NB681- 28V, 6 A, HIGH-CURRENT SYNCHRONOUS BUCK CONVERTER WITH 2-BIT VID

NB681 Rev. 1.04

www.MonolithicPower.com

4

12/28/2017

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© 2017 MPS. All Rights Reserved.

ELECTRICAL CHARACTERISTICS

VIN = 12 V, 3V3 = 3.3 V, TJ = 25C, LP# = 1, C1 = 1, C0 = 0, Mode = 0, unless otherwise noted.

Parameters

Symbol

Condition

Min

Typ

Max

Units

Supply current

3V3 supply current in normal

mode

I3V3

VEN = 3.3 V,VLP# = 3.3 V,

VOUT = 1 V

150

μA

3V3 supply current in LP# mode

I3V3 LP#

VEN = 3.3 V,VLP# = 0

30

μA

3V3 shutdown current

I3V3 SDN

VEN = 0 V

1

μA

MOSFET

High-side switch on resistance

HSRDS-ON

36

mΩ

Low-side switch on resistance

LSRDS-ON

13

mΩ

Switch leakage

SWLKG

VEN = 0 V, VSW = 0 V

0

1

μA

Current limit

Low-side valley current limit

ILIMIT_LS

7

7.6

8.3

A

Switching frequency and minimum off timer

Switching frequency

(5)

FS

Default

750

kHz

Constant on timer

Ton

VIN = 5 V, VOUT = 1.2 V

250

330

400

ns

Minimum on time

(5)

TON Min

50

ns

Minimum off time

(5)

TOFF Min

250

ns

Over-voltage and under-voltage protection

OVP threshold

VOVP

VFB

120%

130%

135%

VREF

UVP-1 threshold

VUVP

VFB

70%

75%

80%

VREF

UVP-1 hold off timer

(5)

TOC

VOUT = 60% VREF

64

μs

UVP-2 threshold

VUVP

VFB

45%

50%

55%

VREF

Reference and soft start

Internal reference voltage

VREF,

MODE=0

LP# = 0

(5)

0

mV

LP# = 1, C1 = 0, C0 = 0

850

mV

LP# = 1, C1 = 0, C0 = 1

875

mV

LP# = 1, C1 = 1, C0 = 0

940

950

960

mV

LP# = 1, C1 = 1, C0 = 1

975

mV

VREF,

MODE=Float

LP# = 0

700

mV

LP# = 1, C1 = 0, C0 = 0

850

mV

LP# = 1, C1 = 0, C0 = 1

900

mV

LP# = 1, C1 = 1, C0 = 0

950

mV

LP# = 1, C1 = 1, C0 = 1

1000

mV

VREF,

MODE=100k

LP# = 0

(5)

0

mV

LP# = 1, C1 = 0, C0 = 0

800

mV

LP# =1, C1 = 0, C0 = 1

950

mV

LP# = 1, C1 = 1, C0 = 0

990

1000

1010

mV

LP# = 1, C1 = 1, C0 = 1

1050

mV