Features

• Low Value DCR Current Sensing
• Programmable DCR Temperature Compensation
• ±0.5% 0.6V Output Voltage Accuracy
• Dual True Remote Sensing Differential Amplifiers
• Optional Fast Transient Operation
• Phase-Lockable Fixed Frequency 250kHz to 720kHz
• Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise
• Dual N-Channel MOSFET Synchronous Drive
• Wide V_IN Range: 4.5V to 38V Operation
• Output Voltage Range with Low DCR: 0.6V to 3.5V, without Low DCR: 0.6V to 5V
• Adjustable Soft-Start Current Ramping or Tracking
• Foldback Output Current Limiting
• Clock Input and Output for Up to 12-Phase Operation
• Short-Circuit Soft Recovery
• Output Overvoltage Protection
• Power Good Output Voltage Monitor
• 40-Lead QFN Packages

Typical Application

Description

The LTC®3875 is a dual output current mode synchronous step-down DC/DC controller that drives all N-channel synchronous power MOSFET stages. It employs a unique architecture which enhances the signal-to-noise ratio of the current sense signal, allowing the use of very low DC resistance power inductors to maximize the efficiency in high current applications. This feature also reduces the switching jitter commonly found in low DCR applications.

The LTC3875 features two high speed remote sense differential amplifiers, programmable current sense limits from 10mV to 30mV and DCR temperature compensation to limit the maximum output current precisely over temperature.

A unique thermal balancing function adjusts per phase current in order to minimize the thermal stress for multichip single output applications. The LTC3875 also features a precise 0.6V reference with guaranteed accuracy of ±0.5% that provides an accurate output voltage from 0.6V to 3.5V. A 4.5V to 38V input voltage range allows it to support a wide variety of bus voltages. The LTC3875 is available in a low profile 40-lead 6mm × 6mm (0.5mm pitch) and 40-lead 5mm × 5mm (0.4mm pitch) QFN packages.