Various MAX8734 - High-Efficiency, Quad-Output, Main Power-Supply Controllers for Notebook Computers free download

File name MAX8734 - High-Efficiency, Quad-Output, Main Power-Supply Controllers for Notebook Computers.pdf

19-3355; Rev 0; 8/04 High-Efficiency, Quad-Output, Main Power- Supply Controllers for Notebook Computers General Description Features MAX8732/MAX8733/MAX8734 The MAX8732/MAX8733/MAX8734 dual step-down, No Current-Sense Resistor Needed (MAX8734) switch-mode power-supply (SMPS) controllers generate Accurate Current Sense with Current-Sense logic-supply voltages in battery-powered systems. The Resistor (MAX8732/MAX8733) MAX8732/MAX8733/MAX8734 include two pulse-width modulation (PWM) controllers, adjustable from 2V to 5.5V 1.5% Output Voltage Accuracy or fixed at 5V and 3.3V. These devices feature two linear 3.3V and 5V 100mA Bootstrapped Linear regulators providing 5V and 3.3V always-on outputs. Each Regulators linear regulator provides up to 100mA output current with Internal Soft-Start and Soft-Stop Output automatic linear-regulator bootstrapping to the main Discharge SMPS outputs. The MAX8732/MAX8733/MAX8734 include on-board power-up sequencing, a power-good (PGOOD) Quick-PWM with 100ns Load Step Response output, digital soft-start, and internal soft-stop output dis- 3.3V and 5V Fixed or Adjustable Outputs charge that prevents negative voltages on shutdown. (Dual ModeTM) Maxim's proprietary Quick-PWMTM quick-response, con- 4.5V to 24V Input Voltage Range stant on-time PWM control scheme operates without Enhanced Ultrasonic Pulse-Skipping Mode sense resistors and provides 100ns response to load tran- (25kHz min) sients while maintaining a relatively constant switching fre- quency. The unique ultrasonic pulse-skipping mode Power-Good (PGOOD) Signal maintains the switching frequency above 25kHz, which Overvoltage Protection Enable/Disable eliminates noise in audio applications. Other features include pulse skipping, which maximizes efficiency in Ordering Information light-load applications, and fixed-frequency PWM mode, 5V/3V which reduces RF interference in sensitive applications. PIN- PART TEMP RANGE SWITCHING The MAX8732 features a 200kHz/5V and 300kHz/3.3V PACKAGE FREQUENCY SMPS for highest efficiency, while