V

SW

FB

VIN

EN/UVLO

TC

GND

RSET

LM5181-Q1

C

OUT

C

IN

100

F

2.2

F

T

1

V

3 : 1

D

FLY

R

SET

12.1 k:

R

FB

158 k:

D

Z

D

F

SS/BIAS

Output Current (mA)

0

100

200

300

400

500

600

700

60

65

70

75

80

85

90

D002

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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

LM5181-Q1

SNVSBN6 – APRIL 2020

1

1 Features

1

•

AEC-Q100-qualified for automotive applications

–

Device temperature grade 1: –40°C to 125°C

ambient temperature range

•

Functional Safety-Capable

–

Documentation available to aid functional

safety system design

•

Designed for reliable and rugged applications

–

Wide input voltage range of 4.5 V to 65 V with

operation down to 3.5 V after start-up

–

Robust solution with only one component

crossing the isolation barrier

–

±1.5% total output regulation accuracy

–

–

6-ms internal or programmable soft start

–

Input UVLO and thermal shutdown protection

–

Hiccup-mode overcurrent fault protection

–

–40°C to +150°C junction temperature range

•

Integration reduces solution size and cost

–

Integrated 100-V, 0.4-Ω power MOSFET

–

No opto-coupler or transformer auxiliary

–

Internal loop compensation

•

High-efficiency PSR flyback operation

–

Quasi-resonant MOSFET turn-off in BCM

–

Low input quiescent current

–

External bias option for improved efficiency

–

Single- and multi-output implementations

•

Create a custom regulator design using

WEBENCH® Power Designer

•

Ultra-low conducted and radiated EMI signatures

–

Soft switching avoids diode reverse recovery

–

Optimized for CISPR 25 Class 5 requirement

2 Applications

•

Sub-AM band automotive body electronics

•

Automotive HEV/EV powertrain systems

•

Traction inverters: IGBT and SiC gate drivers

•

Isolated bias supplies

3 Description

The LM5181-Q1 is a primary-side regulated (PSR)

flyback converter with high efficiency over a wide

input voltage range of 4.5 V to 65 V. The isolated

output voltage is sampled from the primary-side

flyback

voltage,

eliminating

the

need

for

an

optocoupler, voltage reference, or third winding from

the transformer for output voltage regulation.

The high level of integration results in a simple,

reliable and high-density design with only one

component crossing the isolation barrier. Boundary

conduction mode (BCM) switching enables a compact

magnetic solution and better than ±1.5% load and

line regulation performance. An integrated 100-V

power MOSFET provides output power up to 4 W

with enhanced headroom for line transients.

The LM5181-Q1 converter is qualified to automotive

AEC-Q100 grade 1 and is available in 8-pin WSON

package with 0.8-mm pin pitch and wettable flanks.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

LM5181-Q1

WSON (8)

4.00 mm × 4.00 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Typical Application