Features

• Ultrahigh Efficiency: Over 95% Possible
• Drives N-Channel MOSFET for High Current or P-Channel MOSFET for Low Dropout
• Pin Selectable Burst Mode Operation
• 1% Output Accuracy (LTC1266A)
• Pin Selectable Phase of Topside Driver for Boost or Step-Down Operation
• Wide V_IN Range: 3.5V to 20V
• On-Chip Low-Battery Detector
• High Efficiency Maintained Over Large Current Range
• Low 170µA Standby Current at Light Loads
• Current Mode Operation for Excellent Line and Load Transient Response
• Logic Controlled Micropower Shutdown: I_Q < 40µA
• Short-Circuit Protection
• Synchronous Switching with Nonoverlaping Gate Drives
• Available in 16-Pin Narrow SO Package

Typical Application

Description

The LTC1266 series is a family of synchronous switching regulator controllers featuring automatic Burst Mode™ operation to maintain high efficiencies at low output currents. These devices drive external power MOSFETs at switching frequencies up to 400kHz using a constant off-time current mode architecture providing constant ripple current in the inductor. They can drive either an N-channel or a P-channel topside MOSFET. The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 3.5V to 18V (20V maximum). Constant off-time architecture provides low dropout regulation limited only by the R_DS(ON) of the topside MOSFET (when using the P-channel) and the resistance of the inductor and current sense resistor. The LTC1266 series combines synchronous switching for maximum efficiency at high currents with an automatic low current operating mode, called Burst Mode operation, which reduces switching losses. Standby power is reduced to only 1mW at V_IN = 5V (at I_{OUT = 0). Load currents in Burst Mode operation are typically 0mA to 500mA.}