Texas Instruments LM3485 PFET Buck Controller IC, 4.5V to 35V, VSSOP-8

Texas Instruments LM3485 PFET Buck Controller IC is a hysteretic, non-synchronous PFET buck controller with an input range of 4.5V to 35V, designed to simplify the development of compact and efficient step-down switching regulators. It is supplied in a VSSOP-8 package.

Overview

The hysteretic control method removes the need for complex control loop compensation and supports stable operation with a wide selection of external components, which can help to shorten development time. The PFET-based design supports ultra-low dropout operation and 100% duty cycle, allowing the regulator to maintain regulation when the input voltage approaches the output voltage. This is particularly valuable in battery-powered systems, where it can extend usable battery life. The design also maintains high efficiency at light loads without increased output ripple.

Key Features

• Control Methodology: Easy-to-use hysteretic control
• Efficiency: Delivers up to 93% efficiency
• Duty Cycle: Supports 100% duty cycle for ultra-low dropout operation
• Protection: Integrated cycle-by-cycle current limit
• Green Product: Manufactured with no antimony or bromine (no Sb/Br)

Protection

Cycle-by-cycle current limit protection enhances system reliability. The protection is implemented by measuring the voltage across the PFET's own RDS(ON), which removes the need for an external current-sense resistor. The current limit threshold is adjusted with a single external resistor, allowing designers to set protection for different output current requirements.

Physical Specifications

• Width: 3.3
• Depth: 1.5
• Height: 4.3
• Weight: 0.054 g

Applications

This controller is suited to step-down (buck) switching regulator designs, battery-powered systems and general power management applications.