LM5166DRCT

The LM5166 is an easy-to-use, compact 3V to 65V ultra-low IQ synchronous buck converter that delivers high efficiency across a wide input voltage and load current range. The device integrates high-side and low-side power MOSFETs, capable of providing up to 500mA output current, with output voltage options including fixed (3.3V or 5V) and adjustable. The converter is designed to simplify implementation while optimizing performance for target applications. PFM mode ensures optimal efficiency under light-load conditions, and COT control achieves near-constant operating frequency. Neither control scheme requires loop compensation, while also enabling excellent line and load transient response and short PWM on-time at high step-down conversion ratios. The high-side P-channel MOSFET supports 100% duty cycle operation to ensure minimum dropout voltage and does not require a bootstrap capacitor for gate drive. Current limit setpoints can be adjusted to optimize inductor selection for specific load current requirements. Startup sequencing options — selectable and adjustable — include minimum delay (no soft-start), internal fixed value (900μs), and externally programmable soft-start using a capacitor. An open-drain PGOOD indicator supports sequencing, fault reporting, and output voltage monitoring. The LM5166 is available in a 10-pin VSON package with 0.5mm pin pitch.

Applications

• Factory and building automation
• Automotive and battery-powered applications
• High-voltage LDO replacement
• Low-power bias supply

Key features

• 3V to 65V wide input voltage range
• 9.7μA no-load quiescent current
• -40°C to 150°C junction temperature range
• Fixed (3.3V, 5V) or adjustable output voltage options
• Compliant with EN55022/CISPR 22 EMI standards
• Integrated 1Ω PFET buck switch with 100% duty cycle support for low dropout
• Integrated 0.5Ω NFET synchronous rectifier, no external Schottky diode required
• Programmable peak current limit: 500mA, 300mA, or 200mA load
• Selectable PFM or COT mode operation
• 1.223V ±1.2% internal voltage reference
• Switching frequency up to 600kHz
• 900μs internal or externally adjustable soft-start
• Diode emulation and pulse-skip mode for ultra-high efficiency at light load
• No loop compensation or bootstrap components required
• Precision enable and input UVLO with hysteresis
• Open-drain power-good indicator
• Thermal shutdown protection with hysteresis
• Pin-to-pin compatible with LM5165
• 10-pin 3mm×3mm SON package
• Create custom regulator designs using WEBENCH Power Designer