LM2744 Datasheet | National Semiconductor

Description The LM2744 is a high-speed synchronous buck regulator controller with an externally adjustable reference voltage (between 0.5V to 1.5V). It can provide simple down conversion to output voltages as low as 0.5V. Though the control sections of the IC are rated for 3 to 6V, the driver sections are designed to accept input supply rails as high as 16V. The use of adaptive non-overlapping MOSFET gate drivers helps avoid potential shoot-through problems while maintaining high efficiency. The IC is designed for the more cost-effective option of driving only N-channel MOSFETs in both the highside and low-side positions. It senses the low-side switch voltage drop for providing a simple, adjustable current limit. The fixed-frequency voltage-mode PWM control architecture is adjustable from 50 k Hz to 1 MHz with one external resistor. This wide range of switching frequency gives the power supply designer the flexibility to make better tradeoffs between ponent size, cost and efficiency. Features include soft-start, input undervoltage lockout (UVLO) and Power Good (based on both undervoltage and overvoltage detection). In addition, the shutdown pin of the IC can be used for providing startup delay, and the soft-start pin can be used for implementing precise tracking, for the purpose of sequencing with respect to an external rail. Features Power stage input voltage from 1V to 16V Control stage input voltage from 3V to 6V Output voltage adjustable down to 0.5V Power good flag and shutdown Output overvoltage and undervoltage detection External reference voltage 0.5V to 1.5V Low-side adjustable current sensing Adjustable soft-start Tracking and sequencing with shutdown and soft start pins n Switching frequency from 50 k Hz to 1 MHz n TSSOP-14 package n n n n n n n n n Applications n n n n n 3.3V Buck Regulation Cable Modem, DSL and ADSL Laser Jet and Ink Jet Printers Low Voltage Power Modules DSP, ASIC, Core and I/O Typical Application © 2004 National...