Dual High Efficiency SO-16 Step-Down Switching Regulator Controllers

The LTC1143 series is a dual step-down switching regulator controller featuring automatic Burst Mode™ operation to maintain high efficiencies at low output currents. This device is composed of two separate regulator blocks, each driving an external power MOSFET at switching frequencies up to 400kHz using a constant off-time current mode architecture. Both fixed and adjustable voltages are available.

The operating current level for both regulators is user-programmable via an external current sense resistor. Wide input supply range allows operation from 4V to 14V (16V maximum). The LTC1143L and LTC1143L-ADJ extend operation to VIN = 3.5V. 100% duty cycle provides low dropout regulation limited only by the RDS(ON) of the external MOSFET and resistance of the inductor and current sense resistor.

The LTC1143 series is ideal for applications requiring dual output voltages with high conversion efficiencies over a wide load current range in a small amount of board space.

Applications

* Personal Digital Assistants

* Notebook and Palmtop Computers

* Battery-Operated Digital Devices

* Portable Instruments

* DC Power Distribution Systems

* Dual Outputs LTC1143, LTC1143L: 3.3V, 5V LTC1143L-ADJ: Dual Adjustable

* Very High Efficiency: Over 95% Possible

* Current Mode Operation for Excellent Line and Load Transient Response

* High Efficiency Maintained over Three Decades of Output Current

* Low Standby Current at Light Loads: 160µA/Output

* Logic-Controlled Shutdown (LTC1143, LTC1143L)

* Wide VIN Range: 3.5V to 16V (LTC1143L, LTC1143L-ADJ)

* Very Low Dropout Operation: 100% Duty Cycle

* Available in Narrow 16-Pin SO Package