TL497ACNE4

The LM5157 is a wide input range, non-synchronous boost converter with an integrated 50-V power switch. The device supports boost, SEPIC, and flyback topologies. It can start up from a single-cell battery as low as 2.9 V, and if the BIAS pin voltage exceeds 2.9 V, it can operate with input supply voltages as low as 1.5 V. The BIAS pin is rated up to 45 V (50 V maximum). Switching frequency is dynamically programmable via an external resistor from 100 kHz to 2.2 MHz. Operating at 2.2 MHz reduces AM band interference, enabling a smaller solution size and faster transient response. To reduce power supply EMI, the device offers optional dual random spread spectrum, which reduces EMI across a wide frequency range. Accurate peak current limiting across the input voltage range prevents over-design of the power inductor. Low operating current and pulse-skipping operation improve light-load efficiency. Built-in protection features include overvoltage protection, line UVLO, thermal shutdown, and optional hiccup-mode overload protection. Additional features include low shutdown IQ, programmable soft-start, precision reference, power-good indicator, and external clock synchronization.

Applications

• Battery-powered wide-input boost, SEPIC, and flyback converters
• LED bias supply
• Optocoupler-free multiple-output flyback
• Portable speaker applications
• Power modules
• Industrial PLC
• Hold-up capacitor charger
• Audio amplifier power supply
• Piezoelectric driver/motor driver bias supply

Key features

• Wide operating range for battery applications
• Input operating voltage range: 2.9 V to 45 V
• Maximum output voltage: 48 V (50-V maximum)
• Minimum boost supply voltage of 1.5 V when BIAS ≥ 2.9 V
• Input transient protection up to 50 V
• Minimizes battery drain
• Low shutdown current
• Low operating current
• Small solution size, low cost
• Switching frequency up to 2.2 MHz
• 16-pin QFN package (3 mm × 3 mm)
• Integrated error amplifier enables primary-side regulation without optocoupler in flyback applications
• Accurate current limiting
• EMI suppression capability
• Optional dual random spread spectrum
• Leadless package
• Low power dissipation for higher efficiency
• Integrated 45-mΩ RDSON switch
• Fast switching speed with low switching losses
• Avoids AM band interference and crosstalk
• Optional clock synchronization
• Dynamically programmable switching frequency from 100 kHz to 2.2 MHz
• Integrated protection features
• Constant current limiting across input voltage range
• Optional hiccup mode overload protection
• Programmable line UVLO
• OVP protection
• Thermal shutdown
• Feedback reference accuracy of ±1%
• Adjustable soft-start
• PGOOD indicator
• Custom designs available using WEBENCH Power Designer with LM5157x