LTC1266

Features:

Ultra-High 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  Range: 3.5V to 20V_IN On-Chip Low-Battery Detector High Efficiency Maintained over Large Current Range Low 170A Standby Current at Light Loads Current Mode Operation for Excellent Line and Load Transient Response Logic Controlled Micropower Shutdown: I  < 40 A_Q Short Circuit Protection Synchronous Switching with Nonoverlaping Gate DrivesAvailable in 16-Pin Narrow SO Package.


Application

Notebook and Palmtop Computers Portable Instruments Cellular Telephones DC Power Distribution Systems GPS Systems


Pinout




Specifications

Input Supply Voltage (Pins 2, 5).................. 20V to 0.3V
Continuous Output Current (Pins 1, 16) ................  50mA
Sense Voltages (Pins 8, 9).......................... 13V to 0.3V
PINV, BINH, SHDN, LB_IN
    (Pins 3, 4, 11, 13) ...................................20V to 0.3V
LB_OUT  Output Current............................................ 12mA
Operating Ambient Temperature Range..... 0°C to 70°C
Extended Commercial
    Temperature Range..........................  40°C to 85°C
Junction Temperature (Note 1).............................. 125°C
Storage Temperature Range...............  65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C


Description

The LTC^(R) 1266 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 of LTC1266 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 regu- lation limited only by the R  of the topside MOSFET DS(ON) (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 Modeoperation, which reduces switching losses. Standby power is re- duced to only 1mW at V  = 5V (at I  = 0). Load currents IN OUT in Burst Modeoperation are typically 0mA to 500mA.