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.