The MAX6397/MAX6398 are small, high-voltage overvoltage protection circuits. These devices disconnect the output load or limit the output voltage during an input overvoltage condition. These devices are ideal for applications that must survive high-voltage transients such as those found in industrial applications.The MAX6397/MAX6398 monitor the input or output voltages and control an external n-channel MOSFET to isolate or limit the load from overvoltage transient energy. When the monitored input voltage is below the user-adjustableovervoltage threshold, the external n-channel MOSFET is turned on by the GATE output. In this mode, the internal charge pump fully enhances the n-channelMOSFET with a 10V gate-to-source voltage.When the input voltage exceeds the overvoltage threshold, the protection can disconnect the load from the input by quickly forcing the GATE output low. In some applications, disconnecting the output from the load is not desirable. In these cases, the protection circuit can be configured to act as a voltage limiter where the GATE output sawtooths to limit the voltage to the load.The MAX6397 also offers an always-on linear regulator that is capable of delivering up to 100mA of output current. This high-voltage linear regulator consumes only 37µA of quiescent current.The regulator is offered with output options of 5V, 3.3V, 2.5V, or 1.8V. An open-drain, power-good output (POK) asserts when the regulator output falls below 92.5% or 87.5% of its nominal voltage.The MAX6397/MAX6398 include internal thermal-shutdown protection, disabling the external MOSFET and linear regulator if the chip reaches overtemperatureconditions. The devices operate over a wide 5.5V to 72V supply voltage range, are available in small TDFN packages, and are fully specified from -40°C to+125°C.ApplicationsFireWire®IndustrialNotebook ComputersWall Cube Power Devices

The MAX6495–MAX6499 is a family of small, low-current, overvoltage-protection circuits for high-voltage transient systems such as those found in automotive and industrial applications. These devices monitor the input voltage and control an external nMOSFET switch to isolate the load at the output during an input overvoltage condition. The MAX6495–MAX6499 operateover a wide supply voltage range from +5.5V to +72V.The gate of the nMOSFET is driven high while the monitored input is below the user-adjustable overvoltage threshold. An integrated charge-pump circuit provides a 10V gate-to-source voltage to fully enhance the nMOSFET. When the input voltage exceeds the user-adjusted overvoltage threshold, the gate of the MOSFET is quickly pulled low, disconnecting the load from the input. In some applications, disconnecting the output from the load is not desirable. In these cases, the protection circuit can be configured to act as a voltage limiter where the GATE output sawtooths to limit the voltage to the load (MAX6495/MAX6496/MAX6499).The MAX6496 supports lower input voltages and reduces power loss by replacing the external reverse battery diode with an external series pMOSFET. The MAX6496 generates the proper bias voltage to ensure that the pMOSFET is on during normal operations. The gate-to-source voltage is clamped during load-dump conditions, and the p-channel MOSFET is off during reverse-battery conditions.The MAX6497/MAX6498 feature an open-drain, undedicated comparator that notifies the system if the output falls below the programmed threshold. The MAX6497keeps the MOSFET switch latched off until either the input power or the active-low SHDN pin is cycled. The MAX6498 will autoretry when VOVSET falls below 130mV.These devices are available in small, thermally enhanced, 6-pin and 8-pin TDFN packages and are fully specified from -40°C to +125°C.ApplicationsAutomotiveFireWire®IndustrialNotebook ComputersTelecom/Servers/Networking

The MAX6495–MAX6499 is a family of small, low-current, overvoltage-protection circuits for high-voltage transient systems such as those found in automotive and industrial applications. These devices monitor the input voltage and control an external nMOSFET switch to isolate the load at the output during an input overvoltage condition. The MAX6495–MAX6499 operateover a wide supply voltage range from +5.5V to +72V.The gate of the nMOSFET is driven high while the monitored input is below the user-adjustable overvoltage threshold. An integrated charge-pump circuit provides a 10V gate-to-source voltage to fully enhance the nMOSFET. When the input voltage exceeds the user-adjusted overvoltage threshold, the gate of the MOSFET is quickly pulled low, disconnecting the load from the input. In some applications, disconnecting the output from the load is not desirable. In these cases, the protection circuit can be configured to act as a voltage limiter where the GATE output sawtooths to limit the voltage to the load (MAX6495/MAX6496/MAX6499).The MAX6496 supports lower input voltages and reduces power loss by replacing the external reverse battery diode with an external series pMOSFET. The MAX6496 generates the proper bias voltage to ensure that the pMOSFET is on during normal operations. The gate-to-source voltage is clamped during load-dump conditions, and the p-channel MOSFET is off during reverse-battery conditions.The MAX6497/MAX6498 feature an open-drain, undedicated comparator that notifies the system if the output falls below the programmed threshold. The MAX6497keeps the MOSFET switch latched off until either the input power or the active-low SHDN pin is cycled. The MAX6498 will autoretry when VOVSET falls below 130mV.These devices are available in small, thermally enhanced, 6-pin and 8-pin TDFN packages and are fully specified from -40°C to +125°C.ApplicationsAutomotiveFireWire®IndustrialNotebook ComputersTelecom/Servers/Networking

The MAX6495–MAX6499 is a family of small, low-current, overvoltage-protection circuits for high-voltage transient systems such as those found in automotive and industrial applications. These devices monitor the input voltage and control an external nMOSFET switch to isolate the load at the output during an input overvoltage condition. The MAX6495–MAX6499 operateover a wide supply voltage range from +5.5V to +72V.The gate of the nMOSFET is driven high while the monitored input is below the user-adjustable overvoltage threshold. An integrated charge-pump circuit provides a 10V gate-to-source voltage to fully enhance the nMOSFET. When the input voltage exceeds the user-adjusted overvoltage threshold, the gate of the MOSFET is quickly pulled low, disconnecting the load from the input. In some applications, disconnecting the output from the load is not desirable. In these cases, the protection circuit can be configured to act as a voltage limiter where the GATE output sawtooths to limit the voltage to the load (MAX6495/MAX6496/MAX6499).The MAX6496 supports lower input voltages and reduces power loss by replacing the external reverse battery diode with an external series pMOSFET. The MAX6496 generates the proper bias voltage to ensure that the pMOSFET is on during normal operations. The gate-to-source voltage is clamped during load-dump conditions, and the p-channel MOSFET is off during reverse-battery conditions.The MAX6497/MAX6498 feature an open-drain, undedicated comparator that notifies the system if the output falls below the programmed threshold. The MAX6497keeps the MOSFET switch latched off until either the input power or the active-low SHDN pin is cycled. The MAX6498 will autoretry when VOVSET falls below 130mV.These devices are available in small, thermally enhanced, 6-pin and 8-pin TDFN packages and are fully specified from -40°C to +125°C.ApplicationsAutomotiveFireWire®IndustrialNotebook ComputersTelecom/Servers/Networking

The MAX6887/MAX6888 multivoltage supply supervisors provide several voltage-detector inputs, one watchdog input, and three outputs. Each voltage-detectorinput offers a factory-set undervoltage and overvoltage threshold. Manual reset and margin disable inputs offer additional flexibility.The MAX6887 offers six voltage-detector inputs, while the MAX6888 offers four inputs. Output active-low RESET asserts when any input voltage drops below its respective undervoltage threshold or manual reset active-low MR is asserted. Output active-low OV asserts when any input voltage exceeds its respective overvoltage threshold. Monitor standard supply voltages listed in the Selector Guide in the full datasheet.The MAX6887/MAX6888 offer a watchdog timer with an initial and normal timeout periods of 102.4s and 1.6s, respectively. Watchdog output active-low WDO asserts when the watchdog timer expires. Connect active-low WDO to manual reset input active-low MR to generate resets when the watchdog timer expires. RESET, OV, and WDO are active-low, open-drain outputs.The MAX6887/MAX6888 are available in a 5mm x 5mm x 0.8mm, 16-pin thin QFN package and operate over the extended -40°C to +85°C temperature range.ApplicationsMultivoltage SystemsNetworkingServers/Workstations/Storage SystemsTelecom

The LTC3772 is a constant frequency current mode step-down DC/DC controller in a low profile 8-lead SOT-23 (ThinSOT™) and a 3mm × 2mm DFN package. The No RSENSE™ architecture eliminates the need for a current sense resistor, improving efficiency and saving board space.The LTC3772 automatically switches into Burst Mode operation at light loads to increase efficiency at low output current. It consumes only 40µA of quiescent current under a no-load condition.The LTC3772 incorporates an undervoltage lockout feature that shuts down the device when the input voltage falls below 2V. To maximize the runtime from a battery source, the external P-channel MOSFET is turned on continuously in dropout (100% duty cycle). High switching frequency of 550kHz allows the use of a small inductor and capacitors. An internal soft-start smoothly ramps the output voltage from zero to its regulation point. Burst Mode LTC3772 Yes LTC3772B No Applications 1- or 2-Cell Li-Ion Battery-Powered Applications Wireless Devices Portable Computers Distributed Power Systems

The LTC4216 is a positive low voltage Hot Swap™ controller that allows a board to be safely inserted and removed from a live backplane. It controls load voltages ranging from 0V to 6V and isolates a severe fault with instantaneous analog current limiting.An internal high side switch driver controls the gate of an external N-channel MOSFET. An adjustable soft-start limits the rate of change of the inrush current at start-up for a large load capacitor. Together with an analog current limit amplifier, an electronic circuit breaker with adjustable response time provides dual level overcurrent protection. No external gate capacitor is required for the analog current limit loop compensation.The FB pin monitors the output supply voltage and signals the RESET output pin. An ON pin provides on/off control and a FAULT pin indicates the fault status. The LTC4216 is available in the 10-lead MSOP and 12-lead (4mm × 3mm) DFN packages.Applications Electronic Circuit Breaker Live Board Insertion and Removal Industrial High Side Switch/Circuit Breaker Optical Networking

The MAX1556/MAX1556A/MAX1557 are low-operating-current (16µA), fixed-frequency step-down regulators. High efficiency, low-quiescent operating current, low dropout, and minimal (27µA) quiescent current in dropout make these converters ideal for powering portable devices from 1-cell Li-ion or 3-cell alkaline/NiMH batteries. The MAX1556 delivers up to 1.2A; has pin-selectable 1.8V, 2.5V, and 3.3V outputs; and is also adjustable. The MAX1557 delivers up to 600mA; has pin-selectable 1V, 1.3V, and 1.5V outputs; and is also adjustable.The MAX1556/MAX1556A/MAX1557 contain a low-on-resistance internal MOSFET switch and synchronous rectifier to maximize efficiency and dropout performance while minimizing external component count. A proprietary topology offers the benefits of a high fixed-frequency operation while still providing excellent efficiency at both light and full loads. A 1MHz PWM switching frequency keeps components small. Both devices also feature an adjustable soft-start to minimize battery transient loading.The MAX1556/MAX1556A/MAX1557 are available in a tiny 10-pin TDFN (3mm x 3mm) package.ApplicationsCell Phones/SmartphonesDigital Cameras and CamcordersHandheld InstrumentsPDAs and Palmtop ComputersPortable MP3 and DVD Players

The MAX1589A low-dropout linear regulator operates from a +1.62V to +3.6V supply and delivers a guaranteed 500mA continuous load current with a low 175mV dropout. The high-accuracy (±0.5%) output voltage is preset to internally trimmed voltages from +0.75V to +3.0V. An active-low, open-drain reset output remains asserted for at least 70ms after the output voltage reaches regulation. This device is offered in 6-pin thin SOT23 and 6-pin, 3mm x 3mm thin DFN packages.An internal pMOS pass transistor maintains low supply current, independent of load and dropout voltage, making the MAX1589A ideal for portable battery-powered equipment such as personal digital assistants (PDAs), digital still cameras, cell phones, cordless phones, and notebook computers. Other features include logic-controlled shutdown, short-circuit protection, and thermal-overload protection.ApplicationsCD and MP3 PlayersCellular and PCS PhonesDigital Still CamerasHandheld ComputersNotebook ComputersPCMCIA CardsPersonal Digital Assistants (PDAs)

The MAX1630A–MAX1635A are buck-topology, stepdown, switch-mode, power-supply controllers that generate logic-supply voltages in battery-powered systems. These high-performance, dual-/triple-output devices include on-board power-up sequencing, power-good signaling with delay, digital soft-start, secondary winding control, low-dropout circuitry, internal frequency-compensation networks, and automatic bootstrapping.Up to 96% efficiency is achieved through synchronous rectification and Maxim's proprietary Idle Mode™ control scheme. Efficiency is greater than 80% over a 1000:1 load-current range, which extends battery life in system-suspend or standby mode. Excellent dynamic response corrects output load transients caused by the latest dynamic-clock CPUs within five 300kHz clock cycles. Strong 1A on-board gate drivers ensure fast external n-channel MOSFET switching.These devices feature a logic-controlled and synchronizable, fixed-frequency, pulse-width-modulation (PWM) operating mode. This reduces noise and RF interference in sensitive mobile communications and pen-entry applications. Asserting the Active-Low SKIP pin enables fixed-frequency mode for lowest noise under all load conditions.The MAX1630A–MAX1635A include two PWM regulators, adjustable from 2.5V to 5.5V with fixed 5.0V and 3.3V modes. All these devices include secondary feedback regulation, and the MAX1630A/MAX1632A/MAX1633A/MAX1635A each contain 12V/120mA linear regulators. The MAX1631A/MAX1634A include a secondary feedback input (SECFB), plus a control pin (STEER) that selects which PWM (3.3V or 5V) receives the secondary feedback signal. SECFB provides a method for adjusting the secondary winding voltage regulation point with an external resistor-divider, and is intended to aid in creating auxiliary voltages other than fixed 12V.The MAX1630A/MAX1631A/MAX1632A contain internal output overvoltage and undervoltage protection features. The MAX1630A family has improved RF immunity over the MAX1630 family.ApplicationsDesktop CPU Local DC-DC ConvertersNotebook and Subnotebook ComputersPDAs and Mobile Communicators