Analog Devices Inc./Maxim Integrated

The MAX18066/MAX18166 current-mode, synchronous, DC-DC buck converters deliver an output current up to 4A with high efficiency. The devices operate from an input voltage of 4.5V to 16V and provides an adjustable output voltage from 0.606V to 90% of the input voltage. The devices are ideal for distributed power systems, notebook computers, nonportable consumer applications, and preregulation applications.The devices feature a PWM mode operation with an internally fixed switching frequency of 500kHz (MAX18066) and 350kHz (MAX18166) capable of 90% maximum duty cycle. The devices automatically enter skip mode at light loads. The current-mode control architecture simplifies compensation design and ensures a cycle-by-cycle current limit and fast response to line and load transients. A high-gain transconductance error amplifier allows flexibility in setting the external compensation, simplifying the design and allowing for an allceramic design.The synchronous buck regulators feature internal MOSFETs that provide better efficiency than asynchronous solutions, while simplifying the design relative to discrete controller solutions. In addition to simplifying the design, the integrated MOSFETs minimize EMI, reduce board space, and provide higher reliability by minimizing the number of external components.Additional features include an externally adjustable soft-start, independent enable input and power-good output for power sequencing, and thermal shutdown protection. The devices offer overcurrent protection (highside sourcing) with hiccup mode during an output shortcircuit condition. The devices ensure safe startup when powering into a prebiased output.The MAX18066/MAX18166 are available in a 2mm x 2mm, 16-bump (4 x 4 array), 0.5mm pitch wafer-level package (WLP) and are fully specified from -40°C to +85°C.ApplicationsDistributed Power SystemsHome Entertainment (TV and Set-Top Boxes)Network and DatacomPreregulators for Linear RegulatorsServers, Workstations, and Storage

The MAX1807/MAX1808 monitor up to five supply rails for an overvoltage condition and provide a latched output when any one of the five supplies exceeds the trip thresholds. The latched output drives an external P-channel load switch to remove power when an over-voltage condition is detected. The latch is reset when a logic low is input to ON or the power supply is cycled.The MAX1807 provides a 28V open-drain fault output that can be used to trigger an alert, trip a resetable fuse, or for other purposes. The MAX1808 includes a low-battery comparator with hysteresis to drive the DP output high, turning off the external P-channel switch when the input voltage is too low.The MAX1807/MAX1808 are available in a miniature 10-pin µMAX® package.ApplicationsMulti-Output Power SuppliesNotebook ComputersPower-Supply Modules

The MAX1809 is a reversible energy flow, constant-off-time, pulse-width modulated (PWM), step-down DC-DC converter. It is ideal for use in notebook and subnotebook computers that require 1.1V to 5V active termination power supplies. This device features an internal PMOS power switch and internal synchronous rectifier for high efficiency and reduced component count. The internal 90mΩ PMOS power switch and 70mΩ NMOS synchronous-rectifier switch easily deliver continuous load currents up to 3A. The MAX1809 accurately tracks an external reference voltage, produces an adjustable output from 1.1V to VIN, and achieves efficiencies as high as 93%.The MAX1809 uses a unique current-mode, constant-off-time, PWM control scheme that allows the output to source or sink current. This feature allows energy to return to the input power supply that otherwise would be wasted. The programmable constant-off-time architecture sets switching frequencies up to 1MHz, allowing the user to optimize performance trade-offs between efficiency, output switching noise, component size, and cost. The MAX1809 features an adjustable soft-start to limit surge currents during startup, a 100% duty-cycle mode for low-dropout operation, and a low-power shutdown mode that disables the power switches and reduces supply current below 1µA. The MAX1809 is available in a 28-pin QFN with an exposed backside pad, a 28-pin thin QFN, or a 16-pin QSOP.ApplicationsActive Termination Buses (MAX1993)DDR Memory Termination (MAX1993)