LM5166 Synchronous Buck Converter

LM5166 Synchronous Buck Converter

Texas Instruments' LM5166 is a compact, easy-to-use, 3 V to 65 V, ultra-low IQ synchronous buck converter with high efficiency over wide input voltage and load current ranges. With integrated high-side and low-side power MOSFETs, up to 500 mA of output current can be delivered at fixed output voltages of 3.3 V or 5 V, or an adjustable output. The converter is designed to simplify implementation while providing options to optimize the performance for the target application. Pulse frequency modulation (PFM) mode is selected for optimal light-load efficiency or constant on-time (COT) control for nearly constant operating frequency. Neither control scheme require loop compensation while still providing excellent line-and-load transient response and short PWM on-time for large step-down conversion ratios.

The high-side P-channel MOSFET can operate at 100% duty cycle for lowest dropout voltage and does not require a bootstrap capacitor for gate drive. Also, the current limit set point is adjustable to optimize inductor selection for a particular output current requirement. Selectable/adjustable startup timing options include minimum delay (no soft-start), internally fixed (900 μs), and externally programmable soft-start via an external capacitor. An open-drain PGOOD indicator can be used for sequencing and output voltage monitoring. The LM5166 is available in a VSON-10 package with 0.5 mm pin pitch.

Features
  • Wide 3 V to 65 V input voltage range
  • 9.7 µA no-load quiescent current
  • -40°C to ±150°C junction temperature range
  • Meets EN55022 and CISPR 22 EMI standards
  • Integrated 1 Ω PFET buck switch
  • Supports 100% duty cycle for low dropout
  • Integrated 0.5 Ω NFET synchronous rectifier
  • Eliminates external Schottky diode
  • Programmable peak current limit supports:
    • 500 mA, 300 mA, or 200 mA loads
  • Fixed (5 V, 3.3 V) or adjustable VOUT options
  • 1.223 V ±1.2% internal voltage reference
  • Switching frequency up to 600 kHz
  • Two selectable control options:
    • COT for nearly constant frequency
    • PFM for maximum efficiency
  • 900 µs internal or externally adjustable soft-start
  • Diode emulation and pulse skipping for ultra-high light-load efficiency
  • No loop compensation or bootstrap components
  • Precision enable/input UVLO with hysteresis
  • Open-drain power good indicator
  • Thermal shutdown protection with hysteresis
  • Pin-to-pin compatible with the LM5165
  • 10-pin, 3 mm x 3 mm VSON package

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