MAXIM Integrated Products, represented in Australia by Arrow Electronics , has released the MAX1515 constant off time, pulse width modulated (PWM), source/sink step-down dc-dc converter. The switcher is optimised for use in low-voltage active-termination power rails or chipset power supplies in notebook and sub-notebook computers.
It has dual internal, n-channel MOSFET power switches for high efficiency and reduced component count. External Schottky diodes are not required. The internal 40mΩ NMOS power switches source and sink continuous load currents up to 3A. The adjustable output range is 0.5V to 2.7V and achieves efficiency as high as 95%.
The device can be configured as a DDR regulator, producing an output that is exactly half the memory supply rail. The input of the power stage can be taken from the memory supply rail itself, resulting in an efficient power supply that returns the energy to the rail from which it was sourced.
It uses a current-mode, constant-off-time, PWM control scheme. A selectable pulse-skipping mode maintains high efficiency during light-load operation, yet still sources and sinks current on demand. The MAX1515 can also be operated in fixed-PWM mode for low output ripple. The programmable constant-off-time architecture sets switching frequencies up to 1MHz, which allows the user to optimise performance trade-offs among efficiency, output switching noise, component size and cost.
The MAX1515 is available in a 24-pin thin QFN package with an exposed backside pad. The device is screened for the extended industrial temperature range from -40ºC to 85ºC.