LM5166 3V-65V Input, 500mA Synchronous Buck Converter With Ultra-Low Iq | TI.com

This product has been released to the market and is available for purchase. For some products, newer alternatives may be available.
3V-65V Input, 500mA Synchronous Buck Converter With Ultra-Low Iq



The 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. Both control schemes do not require loop compensation while 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 setpoint is adjustable to optimize inductor selection for a particular load current requirement. Selectable and adjustable start-up timing options include minimum delay (no soft start), internally fixed (900 µs), and externally programmable soft start using a capacitor. An open-drain PGOOD indicator can be used for sequencing, fault reporting, and output voltage monitoring. The LM5166 is available in a 10-pin VSON package with 0.5-mm pin pitch.


  • Wide Input Voltage Range of 3 V to 65 V
  • 9.7-µA No-Load Quiescent Current
  • –40°C to 150°C Junction Temperature Range
  • Fixed (3.3-V, 5-V) or Adjustable VOUT Options
  • Meets EN55022 / 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
  • Selectable PFM or COT Mode Operation
  • 1.223-V ±1.2% Internal Voltage Reference
  • Switching Frequency up to 600 kHz
  • 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 and 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 × 3-mm VSON Package
  • Create a Custom Regulator Design Using WEBENCH® Power Designer

All trademarks are the property of their respective owners.

WEBENCH® Power Designer is now even easier to use. Try it now.

WEBENCH® Designer LM5166

Product Option
  Min   Max Range
Vin  V 4.5 to 42V
Vout  V 5.001 to 37V
Iout  A 0 to 0.5A
Ambient Temp  °C -40 to 125°C


Compare all products in Buck converters (integrated switch) Email Download to Excel
Part number Order Vin (Min) (V) Vin (Max) (V) Vout (Min) (V) Vout (Max) (V) Iout (Max) (A) Regulated outputs (#) Switching frequency (Min) (kHz) Switching frequency (Max) (kHz) Iq (Typ) (mA) Features Control mode Duty cycle (Max) (%) Operating temperature range (C) Package Group Rating Type Package size: mm2:W x L (PKG)
LM5166 Order now 3     65     1.23     65     0.5     1     50     600     0.01     Adjustable Current Limit
Light Load Efficiency
Over Current Protection
Power Good
Pre-Bias Start-Up
Synchronous Rectification
UVLO Adjustable    
Constant on-time (COT)     100     -40 to 150     VSON | 10     Catalog     Converter     10VSON: 9 mm2: 3 x 3 (VSON | 10)