
Linear Technology
DESCRIPTION
The LT®1940 is a dual current mode PWM step-down DC/DC converter with internal 2A power switches. Both converters are synchronized to a single 1.1MHz oscillator and run with opposite phases, reducing input ripple current. The output voltages are set with external resistor dividers, and each regulator has independent shutdown and soft-start circuits. Each regulator generates a power-good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs.
FEATURES
■ Wide Input Voltage Range LT1940: 3.6V to 25V LT1940L: 3.6V to 7V
■ Two 1.4A Output Switching Regulators with Internal Power Switches
■ Constant 1.1MHz Switching Frequency
■ Anti-Phase Switching Reduces Ripple
■ Independent Shutdown/Soft-Start Pins
■ Independent Power Good Indicators Ease Supply Sequencing
■ Uses Small Inductors and Ceramic Capacitors
■ Small 16-Lead Thermally Enhanced TSSOP Surface Mount Package
APPLICATIONS
■ Disk Drives
■ DSP Power Supplies
■ Wall Transformer Regulation
■ Distributed Power Regulation
■ DSL Modems
■ Cable Modems