The LT1175 is a negative micropower low dropout regulator. It features 45μA quiescent current, dropping to 10μA in shutdown. A new reference amplifier topology gives precision DC characteristics along with the ability to maintain good loop stability with an extremely wide range of output capacitors. Very low dropout voltage and high efficiency are obtained with a unique power transistor anti-saturation design. Adjustable and fixed 5V versions are available. Several new features make the LT1175 very user-friendly. The SHDN pin can interface directly to either positive or negative logic levels. Current limit is user-selectable at 200mA, 400mA, 600mA and 800mA. The output can be forced to reverse voltage without damage or latch-up. Unlike some earlier designs, the increase in quiescent current during a dropout condition is actively limited. The LT1175 has complete blowout protection with current limiting, power limiting and thermal shutdown. Special attention was given to the problem of high temperature operation with micropower operating currents, preventing output voltage rise under no-load conditions. The LT1175 is available in 8-pin PDIP and SO packages, 3-lead SOT-223 as well as 5-pin surface mount DD and through-hole TO-220 packages. The 8-pin SO package is specially constructed for low thermal resistance.Applications Analog Systems Modems Instrumentation A/D and D/A Converters Interface Drivers Battery-Powered Systems

The LTC1235 provides complete power supply monitoring and battery control functions for microprocessor reset, battery backup, RAM write protection, power failure warning and watchdog timing. The LTC1235 has all the LTC695 features plus conditional battery backup and external reset control. When an out-of-tolerance power supply condition occurs, the reset outputs are forced to active states and the Chip Enable output write-protects external memory. The RESET output is guaranteed to remain logic low with VCC as low as 1V. External reset control is provided by a debounced push-button reset input.The LTC1235 powers the active CMOS RAMs with a charge pumped NMOS power switch to achieve low dropout and low supply current. When primary power is lost, auxiliary power, connected to the battery input pin, provides backup power to the RAMs. The LTC1235 can be programmed by a P signal to either back up the RAMs or not. This extends the battery life in situations where RAM data need not always be saved when power goes down.For an early warning of impending power failure, the LTC1235 provides an internal comparator with a user-defined threshold. An internal watchdog timer is also available, which forces the reset pins to active states when the watchdog input is not toggled prior to the time-out period.Applications Critical µP Power Monitoring Intelligent Instruments Battery-Powered Computers and Controllers Automotive Systems

The MAX749 generates negative LCD-bias contrast voltages from 2V to 6V inputs. Full-scale output voltage can be scaled to -100V or greater, and is digitally adjustable in 64 equal steps by an internal digital-to-analog converter (DAC). Only seven small surface-mount components are required to build a complete supply. The output voltage can also be adjusted using a PWM signal or a potentiometer.A unique current-limited control scheme reduces supply current and maximizes efficiency, while a high switching frequency (up to 500kHz) minimizes the size of external components. Quiescent current is only 60µA max and is reduced to under 15µA in shutdown mode. While shut down, the MAX749 retains the voltage set point, simplifying software control. The MAX749 drives either an external P-channel MOSFET or a PNP transistor.ApplicationsCommunication SystemsLaptop ComputersNotebook ComputersPalmtop ComputersPDAs and Other Handheld DevicesPortable Data-Collection Terminals

The MAX756/MAX757 are CMOS step-up DC-DC switching regulators for small, low input voltage or battery-powered systems. The MAX756 accepts a positive input voltage down to 0.7V and converts it to a higher pin-selectable output voltage of 3.3V or 5V. The MAX757 is an adjustable version that accepts an input voltage down to 0.7V and generates a higher adjustable output voltage in the range from 2.7V to 5.5V. Typical full-load efficiencies for the MAX756/MAX757 are greater than 87%.The MAX756/MAX757 provide three improvements over previous devices. Physical size is reduced-the high switching frequencies (up to 0.5MHz) made possible by MOSFET power transistors allow for tiny (Applications2-Cell and 3-Cell Battery-Operated Equipment3.3V to 5V Step-Up ConversionGlucose MetersMedical InstrumentationPalmtop ComputersPersonal Data Communicators/ComputersPortable Data-Collection Equipment

The MAX756/MAX757 are CMOS step-up DC-DC switching regulators for small, low input voltage or battery-powered systems. The MAX756 accepts a positive input voltage down to 0.7V and converts it to a higher pin-selectable output voltage of 3.3V or 5V. The MAX757 is an adjustable version that accepts an input voltage down to 0.7V and generates a higher adjustable output voltage in the range from 2.7V to 5.5V. Typical full-load efficiencies for the MAX756/MAX757 are greater than 87%.The MAX756/MAX757 provide three improvements over previous devices. Physical size is reduced-the high switching frequencies (up to 0.5MHz) made possible by MOSFET power transistors allow for tiny (Applications2-Cell and 3-Cell Battery-Operated Equipment3.3V to 5V Step-Up ConversionGlucose MetersMedical InstrumentationPalmtop ComputersPersonal Data Communicators/ComputersPortable Data-Collection Equipment

The MAX770-MAX773 step-up switching controllers provide 90% efficiency over a 10mA to 1A load. A unique current-limited pulse-frequency-modulation (PFM) control scheme gives these devices the benefits of pulse-width-modulation (PWM) converters (high efficiency at heavy loads), while using less than 110µA of supply current (vs. 2mA to 10mA for PWM converters).These ICs use tiny external components. Their high switching frequencies (up to 300kHz) allow surface-mount magnetics of 5mm height and 9mm diameter.The MAX770/MAX771/MAX772 accept input voltages from 2V to 16.5V. Output voltages are preset at 5V, (MAX770), 12V (MAX771), and 15V (MAX772); they can also be adjusted using two resistors.The MAX773 accepts inputs from 3V to 16.5V. For a wider input range, it features an internal shunt regulator that allows unlimited higher input voltages. The MAX773's output can be set to 5V, 12V, or 15V, or it can be adjusted with two resistors.The MAX770-MAX773 drive external N-channel MOSFET switches, allowing them to power loads up to 15W. If less power is required, use the MAX756/MAX757 or MAX761/MAX762 step-up switching regulators with on-board MOSFETs.ApplicationsBattery-Powered ApplicationsFlash Memory ProgrammingHigh-Efficiency DC-DC ConvertersPalmtops, Handy TerminalsPortable CommunicatorsPositive LCD-Bias Generators

The MAX774/MAX775/MAX776 inverting switching regulators deliver high efficiency over three decades of load current. A unique current-limited, pulse-frequencymodulated (PFM) control scheme provides the benefits of pulse-width modulation (high efficiency with heavy loads), while using less than 100µA of supplycurrent (vs. 2mA to 10mA for PWM converters). The result is high efficiency over a wide range of loads.These ICs also use tiny external components; their high switching frequency (up to 300kHz) allows for less than 5mm diameter surface-mount magnetics.The MAX774/MAX775/MAX776 accept input voltages from 3V to 16.5V, and have preset output voltages of -5V, -12V, and -15V, respectively. Or, the output voltagecan be user-adjusted with two resistors. Maximum VIN - VOUT differential voltage is limited only by the break-down voltage of the chosen external switch transistor.These inverters use external P-channel MOSFET switches, allowing them to power loads up to 5W. If less power is required, use the MAX764/MAX765/MAX766 inverting switching regulators with on-board MOSFETs.ApplicationsBattery-Powered ApplicationsData CommunicationsHigh-Efficiency DC-DC ConvertersLCD Bias Generators

The MAX774/MAX775/MAX776 inverting switching regulators deliver high efficiency over three decades of load current. A unique current-limited, pulse-frequencymodulated (PFM) control scheme provides the benefits of pulse-width modulation (high efficiency with heavy loads), while using less than 100µA of supplycurrent (vs. 2mA to 10mA for PWM converters). The result is high efficiency over a wide range of loads.These ICs also use tiny external components; their high switching frequency (up to 300kHz) allows for less than 5mm diameter surface-mount magnetics.The MAX774/MAX775/MAX776 accept input voltages from 3V to 16.5V, and have preset output voltages of -5V, -12V, and -15V, respectively. Or, the output voltagecan be user-adjusted with two resistors. Maximum VIN - VOUT differential voltage is limited only by the break-down voltage of the chosen external switch transistor.These inverters use external P-channel MOSFET switches, allowing them to power loads up to 5W. If less power is required, use the MAX764/MAX765/MAX766 inverting switching regulators with on-board MOSFETs.ApplicationsBattery-Powered ApplicationsData CommunicationsHigh-Efficiency DC-DC ConvertersLCD Bias Generators

The MAX793/MAX794/MAX795 microprocessor (µP) supervisory circuits monitor and control the activities of +3.0V/+3.3V µPs by providing backup-battery switchover, among other features such as low-line indication, µP reset, write protection for CMOS RAM, and a watchdog (see the Selector Guide in the full data sheet). The backup-battery voltage can exceed VCC, permitting the use of 3.6V lithium batteries in systems using 3.0V to 3.3V for VCC.The MAX793/MAX795 offer a choice of reset threshold voltage range (denoted by suffix letter): 3.00V to 3.15V (T), 2.85V to 3.00V (S), and 2.55V to 2.70V (R). The MAX794's reset threshold is set externally with a resistor divider. The MAX793/MAX794 are available in 16-pin DIP and narrow SO packages, and the MAX795 comes in 8-pin DIP and SO packages.ApplicationsBattery-Powered Computers/ControllersCritical µP Power MonitoringEmbedded ControllersIntelligent ControllersPortable Equipment

The MAX793/MAX794/MAX795 microprocessor (µP) supervisory circuits monitor and control the activities of +3.0V/+3.3V µPs by providing backup-battery switchover, among other features such as low-line indication, µP reset, write protection for CMOS RAM, and a watchdog (see the Selector Guide in the full data sheet). The backup-battery voltage can exceed VCC, permitting the use of 3.6V lithium batteries in systems using 3.0V to 3.3V for VCC.The MAX793/MAX795 offer a choice of reset threshold voltage range (denoted by suffix letter): 3.00V to 3.15V (T), 2.85V to 3.00V (S), and 2.55V to 2.70V (R). The MAX794's reset threshold is set externally with a resistor divider. The MAX793/MAX794 are available in 16-pin DIP and narrow SO packages, and the MAX795 comes in 8-pin DIP and SO packages.ApplicationsBattery-Powered Computers/ControllersCritical µP Power MonitoringEmbedded ControllersIntelligent ControllersPortable Equipment