Various MAX1999 - High-Efficiency, Quad Output, Main Power- Supply Controllers for Notebook Computers free download

File name MAX1999 - High-Efficiency, Quad Output, Main Power- Supply Controllers for Notebook Computers.pdf

19-2187; Rev 1; 9/04 High-Efficiency, Quad Output, Main Power- Supply Controllers for Notebook Computers General Description Features MAX1777/MAX1977/MAX1999 The MAX1777/MAX1977/MAX1999 dual step-down, No Current-Sense Resistor Needed (MAX1999) switch-mode power-supply (SMPS) controllers generate Accurate Current Sense with Current-Sense logic-supply voltages in battery-powered systems. The Resistor (MAX1777/MAX1977) MAX1777/MAX1977/MAX1999 include two pulse-width 1.5% Output Voltage Accuracy modulation (PWM) controllers, adjustable from 2V to 5.5V 3.3V and 5V 100mA Bootstrapped Linear or fixed at 5V and 3.3V. These devices feature two linear Regulators regulators providing 5V and 3.3V always-on outputs. Internal Soft-Start and Soft-Stop Output Each linear regulator provides up to 100mA output cur- Discharge rent with automatic linear regulator bootstrapping to the Quick-PWM with 100ns Load Step Response main SMPS outputs. The MAX1777/MAX1977/MAX1999 3.3V and 5V Fixed or Adjustable Outputs include on-board power-up sequencing, a power-good (Dual ModeTM) (PGOOD) output, digital soft-start, and internal soft-stop 4.5V to 24V Input Voltage Range output discharge that prevents negative voltages on shut- Ultrasonic Pulse-Skipping Mode (25kHz min) down. Power-Good (PGOOD) Signal Maxim's proprietary Quick-PWMTM quick-response, con- Overvoltage Protection Enable/Disable stant on-time PWM control scheme operates without sense resistors and provides 100ns response to load Ordering Information transients while maintaining a relatively constant switch- ing frequency. The unique ultrasonic pulse-skipping 5V/3V PIN- mode maintains the switching frequency above 25kHz, PART TEMP RANGE SWITCHING PACKAGE which eliminates noise in audio applications. Other fea- FREQUENCY tures include pulse skipping, which maximizes efficiency MAX1777EEI -40