LM5157数据手册集成电路（IC）的稳压器-DC-DC开关稳压器规格书PDF

描述 Description

The LM5157 device is a wide input range, non-synchronous boost converter with integrated 50-V power switch.

The device can be used in boost, SEPIC, and flyback topologies. The device can start up from a single-cell battery with a minimum of 2.9 V. It can operate with an input supply voltage as low as 1.5 V if the BIAS pin is greater than 2.9 V.

The BIAS pin operates up to 45 V (50-V absolute maximum). The switching frequency is dynamically programmable with an external resistor from 100 kHz to 2.2 MHz. Switching at 2.2 MHz minimizes AM band interference and allows for a small solution size and fast transient response. To reduce the EMI of the power supply, the device provides a selectable Dual Random Spread Spectrum, which reduces the EMI over a wide frequency range.

The device features an accurate peak current limit over the input voltage, which avoids overdesigning power inductor. Low operating current and pulse-skipping operation improve efficiency at light loads.

The device has built-in protection features such as overvoltage protection, line UVLO, thermal shutdown, and selectable Hiccup mode overload protection. Additional features include low shutdown IQ, programmable soft start, precision reference, a power-good indicator, and external clock synchronization.

特性 Features

• Suited for wide operating range for battery applications
• 2.9-V to 45-V input operating range
• 48-V maximum output (50-V abs max)
• Minimum boost supply voltage of 1.5 V when BIAS ≥ 2.9 V
• Input transient protection up to 50 V
• Minimized battery drain
• Low shutdown current (IQ ≤ 2.6 µA)
• Low operating current (IQ ≤ 670 µA)


• Small solution size and low cost
• Maximum switching frequency up to 2.2 MHz
• 16-pin QFN package (3 mm × 3 mm)
• Integrated error amplifier allows primary-side regulation without optocoupler (flyback)
• Accurate current limit (see the Device Comparison Table)

• EMI mitigation
• Selectable dual random spread spectrum
• Lead-less package

• Higher efficiency with low-power dissipation
• 45-mΩ RDSON switch
• Fast switching, small switching loss

• Avoid AM band interference and crosstalk
• Optional clock synchronization
• Dynamically programmable wide switching frequency from 100 kHz to 2.2 MHz

• Integrated protection features
• Constant current limiting over input voltage
• Selectable hiccup mode overload protection
• Programmable line UVLO
• OVP protection
• Thermal shutdown

• Accurate ±1% accuracy feedback reference
• Adjustable soft start
• PGOOD indicator
• Create a custom design using the LM5157x with the WEBENCH Power Designer