1 Features

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• Wide input operating range for battery applications

– 3.5-V to 45-V operating range

– 2.97-V to 16-V when BIAS = VCC

– Minimum boost supply voltage 1.5 V when

BIAS ≥ 3.5 V

– Input transient protection up to 50 V

• Minimized battery drain

– Low shutdown current (IQ ≤ 2.6 μA)

– Low operating current (IQ ≤ 480 μA)

• Small solution size and low cost

– Maximum switching frequency of 2.2 MHz

– 12-Pin WSON package (3 mm × 2 mm)

– Integrated error amplifier allows primary-side

regulation without optocoupler (flyback)

– Minimized undershoot during cranking (startstop

application)

• Higher efficiency with low-power dissipation

– 100-mV ±7% Low current limit threshold

– Strong 1.5-A peak standard MOSFET driver

– Supports external VCC supply

• Avoid AM band interference and crosstalk

– Optional clock synchronization

– Dynamically programmable switching frequency

from 100 kHz to 2.2 MHz

• Integrated protection features

– Constant peak current limiting over input

voltage

– Optional hiccup mode short-circuit protection

(see the Device Comparison Table)

– Programmable line UVLO

– OVP protection

– Thermal shutdown

• Accurate ±1% accuracy feedback reference

• Programmable extra slope compensation

• Adjustable soft start

• PGOOD indicator

• Create a custom design using the LM5155x with

the WEBENCH® power designer

2 Applications

• Multiple-output flyback without optocoupler

• LED bias supply

• Wide input boost, SEPIC, flyback power module

• Portable speaker application

• Battery-powered boost, SEPIC, flyback

3 Description

The LM5155x (LM5155 and LM51551) is a wide input

range, non-synchronous boost controller that uses

peak current mode control. The device can be used

in boost, SEPIC, and flyback topologies.

The LM5155x can start up from a 1-cell battery with a

minimum of 2.97 V if the BIAS pin is connected to the

VCC pin. It can operate with the input supply voltage

as low as 1.5 V if the BIAS pin is greater than 3.5 V.