8.3 Recommended Operating Conditions

Over the recommended operating junction temperature range of –40°C to 150°C (unless otherwise specified)(1)

MIN

NOM

MAX

UNIT

VBIAS

Bias input(2)

2.97

45

V

VVCC

VCC voltage(3)

2.97

16

V

VUVLO

UVLO input

0

45

V

VFB

FB input

0

3.7

V

fSW

Typical switching frequency

100

2200

kHz

fSYNC

Synchronization pulse frequency

100

2200

kHz

TJ

Operating junction temperature(4)

–40

150

°C

(1)

Operating Ratings are conditions under the device is intended to be functional. For specifications and test conditions, see Electrical

Characteristics.

(2)

BIAS pin operating range is from 2.97 V to 16 V when VCC is directly connected to BIAS. BIAS pin operating range is from 3.5 V to 45

V when VCC is supplied from the internal VCC regulator.

(3)

This pin voltage should be less than VBIAS + 0.3 V.

(4)

High junction temperatures degrade operating lifetimes. Operating lifetime is de-rated for junction temperatures greater than 125°C.

8.4 Thermal Information

THERMAL METRIC (1)

LM5155x-Q1

UNIT

DSS(WSON)

12 PINS

RθJA

Junction-to-ambient thermal resistance (LM5155EVM-BST)

37.0

°C/W

RθJA

Junction-to-ambient thermal resistance

60.3

°C/W

RθJC(top)

Junction-to-case (top) thermal resistance

60.1

°C/W

RθJB

Junction-to-board thermal resistance

28.8

°C/W

ψJT

Junction-to-top characterization parameter (LM5155EVM-BST)

1.2

°C/W

ψJT

Junction-to-top characterization parameter

2.0

°C/W

ψJB

Junction-to-board characterization parameter (LM5155EVM-BST)

18.7

°C/W

ψJB

Junction-to-board characterization parameter

28.7

°C/W

RθJC(bot)

Junction-to-case (bottom) thermal resistance

7.1

°C/W

(1)

For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application

report.

8.5 Electrical Characteristics

Typical values correspond to TJ = 25°C. Minimum and maximum limits apply over TJ = -40°C to 125°C. Unless otherwise

stated, VBIAS = 12 V, RT = 9.09 kΩ

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

SUPPLY CURRENT

ISHUTDOWN(BIAS)

BIAS shutdown current

VBIAS = 12 V, VUVLO = 0 V

2.6

5

uA

IOPERATING(BIAS)

BIAS operating current

VBIAS = 12 V, VUVLO = 2 V, VFB = VREF,

RT = 220 kΩ

480

540

uA

VCC REGULATOR

VVCC-REG

VCC regulation

VBIAS = 8 V, No load

6.5

6.85

7

V

VCC regulation

VBIAS = 8 V, IVCC = 35 mA

6.5

V

VVCC-UVLO(RISING)

VCC UVLO threshold

VCC rising

2.75

2.85

2.95

V

VCC UVLO hysteresis

VCC falling

0.063

V

IVCC-CL

VCC sourcing current limit

VBIAS = 10 V, VVCC = 0 V

35

105

mA

ENABLE

VEN(RISING)

Enable threshold

EN rising

0.4

0.52

0.7

V

LM5155-Q1, LM51551-Q1

SNVSAY4E – AUGUST 2018 – REVISED JANUARY 2021

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