The LTC2927 provides a simple solution to power supply tracking and sequencing requirements. By selecting a few resistors, the supply can be configured to ramp-up and ramp-down with differing ramp rates, voltage offsets, or time delays relative to other supplies or a master signal.By forcing current into a feedback node of an independent supply, the LTC2927 causes the output to track a ramp signal without inserting any pass element losses. Because the current is controlled in an open-loop manner, the LTC2927 does not affect the transient response or stability of the supply. The compact solution at point of load minimizes the trace length of the DC/DC circuit sensitive FB node. Furthermore, it presents a high impedance when power-up is complete, effectively removing it from the DC/DC circuit.Applications VCORE and VI/O Supply Tracking Microprocessor, DSP and FPGA Supplies Multiple Supply Systems Point-of-Load Supplies

The LTC3458L is a high efficiency, current mode, fixed frequency, step up DC/DC converter with true output disconnect and inrush current limiting. The LTC3458L is rated for up to 6V output and includes a 0.2Ω N-channel MOSFET switch and a 0.3Ω P-channel MOSFET synchronous rectifier. The LTC3458L is well suited for battery powered applications and includes programmable output voltage, switching frequency and loop compensation. The oscillator frequency can be set up to 1.5MHz or synchronized to an external clock.Quiescent current is only 12µA during Burst Mode operation maximizing battery life in portable applications. The Burst Mode current threshold, peak current limit, and softstart are externally programmable. Other features include

The DS1088L is a low-cost clock generator that produces a square-wave output without external timingcomponents. The fixed-frequency oscillator is available in factory-calibrated frequencies from 312kHz to 133MHz. The device has a power-down pin for power-sensitive applications.ApplicationsCable ModemsComputer PeripheralsCopiersPOS TerminalsPrinters

The DS1088L is a low-cost clock generator that produces a square-wave output without external timingcomponents. The fixed-frequency oscillator is available in factory-calibrated frequencies from 312kHz to 133MHz. The device has a power-down pin for power-sensitive applications.ApplicationsCable ModemsComputer PeripheralsCopiersPOS TerminalsPrinters

The DS1089L is a clock generator that produces a spread spectrum (dithered) square-wave output of frequencies from 130kHz to 66.6MHz. The DS1089L is shipped from the factory programmed at a specific frequency. The DS1089L is pin-for-pin compatible with the DS1087L, however, the DS1089L dithers at equal percentages above and below the center frequency. The user still has access to the internal frequency divider, selectable ±1%, ±2%, ±4%, or ±8% dithered output, dithering rate, and programmable output powerdown/disable mode through an I²C-compatible programming interface. All the device settings are stored in nonvolatile (NV) EEPROM allowing it to operate in stand-alone applications. The DS1089L also has power-down and output-enable control pins for power-sensitive applications.ApplicationsCable ModemsComputer PeripheralsCopiersPOS TerminalsPrinters

The DS1388 I²C real-time clock (RTC), supervisor, and EEPROM is a multifunction device that provides a clock/calendar, programmable watchdog timer, power-supply monitor with reset, and 512 bytes of EEPROM. The clock provides hundredths of seconds, seconds, minutes, and hours, and operates in 24-hour or 12-hour format with an AM/PM indicator. The calendar provides day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. A watchdog timer provides a reset for an unresponsive microprocessor. It is programmable in 10ms intervals from 0.01 to 99.99 seconds. A temperature-compensated voltage reference and comparator circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to the backup supply and drives the reset output to the active state. The backup supply maintains time and date operation in the absence of VCC. When VCC returns to nominal levels, the reset is held low for a period to allow the power supply and processor to stabilize. The device also has a pushbutton reset controller, which debounces a reset input signal. The device is accessed through an I²C serial interface.ApplicationsNetwork-Interface CardsPoint-of-Sale EquipmentPortable InstrumentationWireless Equipment

The DS1388 I²C real-time clock (RTC), supervisor, and EEPROM is a multifunction device that provides a clock/calendar, programmable watchdog timer, power-supply monitor with reset, and 512 bytes of EEPROM. The clock provides hundredths of seconds, seconds, minutes, and hours, and operates in 24-hour or 12-hour format with an AM/PM indicator. The calendar provides day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. A watchdog timer provides a reset for an unresponsive microprocessor. It is programmable in 10ms intervals from 0.01 to 99.99 seconds. A temperature-compensated voltage reference and comparator circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to the backup supply and drives the reset output to the active state. The backup supply maintains time and date operation in the absence of VCC. When VCC returns to nominal levels, the reset is held low for a period to allow the power supply and processor to stabilize. The device also has a pushbutton reset controller, which debounces a reset input signal. The device is accessed through an I²C serial interface.ApplicationsNetwork-Interface CardsPoint-of-Sale EquipmentPortable InstrumentationWireless Equipment

The low-voltage serial-peripheral interface (SPI™) DS1390/DS1391/DS1394 and the low-voltage 3-wire DS1392/DS1393 real-time clocks (RTCs) are clocks/calendars that provide hundredths of a second, seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. One programmable time-of-day alarm is provided. A temperature-compensated voltage reference monitors the status of VCC and automatically disables the bus interface and switches to the backup supply if a power failure is detected. On the DS1390, a single open drain output provides a CPU interrupt or a square wave at one of four selectable frequencies. The DS1391 replaces the SQW/active-low INT pin with an active-low RST output/debounced input.The DS1390, DS1391, and DS1394 are programmed serially through an SPI-compatible, bidirectional bus. The DS1392 and DS1393 communicate over a 3-wire serial bus, and the extra pin is used for either a separate interrupt pin or an active-low RST output/debounced input.All five devices are available in a 10-pin µSOP package, and are rated over the industrial temperature range.ApplicationsEmbedded Time StampingGPS/Telematics DevicesHandheld DevicesMedical Devices

The low-voltage serial-peripheral interface (SPI™) DS1390/DS1391/DS1394 and the low-voltage 3-wire DS1392/DS1393 real-time clocks (RTCs) are clocks/calendars that provide hundredths of a second, seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. One programmable time-of-day alarm is provided. A temperature-compensated voltage reference monitors the status of VCC and automatically disables the bus interface and switches to the backup supply if a power failure is detected. On the DS1390, a single open drain output provides a CPU interrupt or a square wave at one of four selectable frequencies. The DS1391 replaces the SQW/active-low INT pin with an active-low RST output/debounced input.The DS1390, DS1391, and DS1394 are programmed serially through an SPI-compatible, bidirectional bus. The DS1392 and DS1393 communicate over a 3-wire serial bus, and the extra pin is used for either a separate interrupt pin or an active-low RST output/debounced input.All five devices are available in a 10-pin µSOP package, and are rated over the industrial temperature range.ApplicationsEmbedded Time StampingGPS/Telematics DevicesHandheld DevicesMedical Devices

The low-voltage serial-peripheral interface (SPI™) DS1390/DS1391/DS1394 and the low-voltage 3-wire DS1392/DS1393 real-time clocks (RTCs) are clocks/calendars that provide hundredths of a second, seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. One programmable time-of-day alarm is provided. A temperature-compensated voltage reference monitors the status of VCC and automatically disables the bus interface and switches to the backup supply if a power failure is detected. On the DS1390, a single open drain output provides a CPU interrupt or a square wave at one of four selectable frequencies. The DS1391 replaces the SQW/active-low INT pin with an active-low RST output/debounced input.The DS1390, DS1391, and DS1394 are programmed serially through an SPI-compatible, bidirectional bus. The DS1392 and DS1393 communicate over a 3-wire serial bus, and the extra pin is used for either a separate interrupt pin or an active-low RST output/debounced input.All five devices are available in a 10-pin µSOP package, and are rated over the industrial temperature range.ApplicationsEmbedded Time StampingGPS/Telematics DevicesHandheld DevicesMedical Devices

The low-voltage serial-peripheral interface (SPI™) DS1390/DS1391/DS1394 and the low-voltage 3-wire DS1392/DS1393 real-time clocks (RTCs) are clocks/calendars that provide hundredths of a second, seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. One programmable time-of-day alarm is provided. A temperature-compensated voltage reference monitors the status of VCC and automatically disables the bus interface and switches to the backup supply if a power failure is detected. On the DS1390, a single open drain output provides a CPU interrupt or a square wave at one of four selectable frequencies. The DS1391 replaces the SQW/active-low INT pin with an active-low RST output/debounced input.The DS1390, DS1391, and DS1394 are programmed serially through an SPI-compatible, bidirectional bus. The DS1392 and DS1393 communicate over a 3-wire serial bus, and the extra pin is used for either a separate interrupt pin or an active-low RST output/debounced input.All five devices are available in a 10-pin µSOP package, and are rated over the industrial temperature range.ApplicationsEmbedded Time StampingGPS/Telematics DevicesHandheld DevicesMedical Devices

The low-voltage serial-peripheral interface (SPI™) DS1390/DS1391/DS1394 and the low-voltage 3-wire DS1392/DS1393 real-time clocks (RTCs) are clocks/calendars that provide hundredths of a second, seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. One programmable time-of-day alarm is provided. A temperature-compensated voltage reference monitors the status of VCC and automatically disables the bus interface and switches to the backup supply if a power failure is detected. On the DS1390, a single open drain output provides a CPU interrupt or a square wave at one of four selectable frequencies. The DS1391 replaces the SQW/active-low INT pin with an active-low RST output/debounced input.The DS1390, DS1391, and DS1394 are programmed serially through an SPI-compatible, bidirectional bus. The DS1392 and DS1393 communicate over a 3-wire serial bus, and the extra pin is used for either a separate interrupt pin or an active-low RST output/debounced input.All five devices are available in a 10-pin µSOP package, and are rated over the industrial temperature range.ApplicationsEmbedded Time StampingGPS/Telematics DevicesHandheld DevicesMedical Devices

The DS1825 digital thermometer provides 9 to 12-bit centigrade temperature measurements and has an alarmfunction with NV user-programmable upper and lower trigger points. The DS1825 communicates over a 1-Wire® busthat by definition requires only one data line (and ground) for communication with a central microprocessor. It hasan operating temperature range of -55°C to +125°C and is accurate to ±0.5°C over the range of -10°C to +85°C. Inaddition, the DS1825 can derive power directly from the data line (“parasite power”), eliminating the need for anexternal power supply.Each DS1825 has a unique 64-bit serial code, which allows multiple DS1825s to function on the same 1-Wire bus;thus, it is simple to use one microprocessor to control many DS1825s distributed over a large area. In addition, the4-bit location address can be used to identify specific temperature sensors in the system without requiring a widelookup table. Applications that can benefit from this feature include HVAC environmental controls, temperaturemonitoring systems inside buildings, equipment or machinery, and process monitoring and control systems.ApplicationsConsumer ProductsIndustrial SystemsThermally Sensitive SystemsThermometersThermostatic Controls

The DS1856 dual, temperature-controlled, nonvolatile (NV) variable resistors with three monitors consists of two 256-position, linear, variable resistors; three analog monitor inputs (MON1, MON2, MON3); and a direct-to-digital temperature sensor. The device provides an ideal method for setting and temperature-compensating bias voltages and currents in control applications using minimal circuitry. The variable resistor settings are stored in EEPROM memory and can be accessed over the 2-wire serial bus.Relative to other members of the family, the DS1856 is essentially a DS1859 with a DS1852-friendly memory map. In particular, the DS1856 can be configured so the 128 bytes of internal Auxiliary EEPROM memory is mapped into Main Device Table 00h and Table 01h, maintaining compatibility between both the DS1858/DS1859 and the DS1852. The DS1856 also features password protection equivalent to the DS1852, further enhancing compatibility between the two.ApplicationsDiagnostic MonitoringInstrumentation and Industrial ControlsOptical TransceiversOptical TranspondersRF Power Amps

The iButton® temperature/humidity logger (DS1923) is a rugged, self-sufficient system that measures temperature and/or humidity and records the result in a protected memory section. The recording is done at a user-defined rate. A total of 8192 8-bit readings or 4096 16-bit readings taken at equidistant intervals ranging from 1s to 273hrs can be stored. In addition to this, there are 512 bytes of SRAM for storing application-specific information and 64 bytes for calibration data. A mission to collect data can be programmed to begin immediately, or after a user-defined delay or after a temperature alarm. Access to the memory and control functions can be password-protected. The DS1923 is configured and communicates with a host-computing device through the serial 1-Wire® protocol, which requires only a single data lead and a ground return. Every DS1923 is factory-lasered with a guaranteed unique 64-bit registration number that allows for absolute traceability. The durable stainless-steel package is highly resistant to environmental hazards such as dirt, moisture, and shock. Accessories permit the DS1923 to be mounted on almost any object, including containers, pallets and bags.ApplicationsEnvironmental Studies/MonitoringTemperature and Humidity Logging in Food Preparation and ProcessingTransportation of Temperature- and Humidity-Sensitive Goods, Industrial ProductionWarehouse Monitoring

The DS2711 and DS2712 are ideal for in-system or stand-alone charging of 1 or 2 AA or AAA NiMH 'loose' cells. Temperature, voltage, and charge time are monitored to provide proper fast charging control algorithms for nickel metal hydride (NiMH) batteries. Battery tests are included to detect defective or inappropriate cells such as alkaline primary batteries. The DS2711/DS2712 support series and parallel topologies, with independent monitoring and control of each cell. Charging of NiCd chemistry cells is also supported.ApplicationsDesktop/Stand-Alone Chargers (AAA/AA)Digital Still CamerasGamingMusic PlayersToys

The DS2711 and DS2712 are ideal for in-system or stand-alone charging of 1 or 2 AA or AAA NiMH 'loose' cells. Temperature, voltage, and charge time are monitored to provide proper fast charging control algorithms for nickel metal hydride (NiMH) batteries. Battery tests are included to detect defective or inappropriate cells such as alkaline primary batteries. The DS2711/DS2712 support series and parallel topologies, with independent monitoring and control of each cell. Charging of NiCd chemistry cells is also supported.ApplicationsDesktop/Stand-Alone Chargers (AAA/AA)Digital Still CamerasGamingMusic PlayersToys

The DS2711 and DS2712 are ideal for in-system or stand-alone charging of 1 or 2 AA or AAA NiMH 'loose' cells. Temperature, voltage, and charge time are monitored to provide proper fast charging control algorithms for nickel metal hydride (NiMH) batteries. Battery tests are included to detect defective or inappropriate cells such as alkaline primary batteries. The DS2711/DS2712 support series and parallel topologies, with independent monitoring and control of each cell. Charging of NiCd chemistry cells is also supported.ApplicationsDesktop/Stand-Alone Chargers (AAA/AA)Digital Still CamerasGamingMusic PlayersToys

The DS28E01-100 combines 1024 bits of EEPROM with challenge-and-response authentication security implemented with the ISO/IEC 10118-3 Secure Hash Algorithm (SHA-1). The 1024-bit EEPROM array is configured as four pages of 256 bits with a 64-bit scratchpad to perform write operations. All memory pages can be write protected, and one page can be put in EPROM-emulation mode, where bits can only be changed from a 1 to a 0 state. Each DS28E01-100 has its own guaranteed unique 64-bit ROM registration number that is factory lasered into the chip. The DS28E01-100 communicates over the single-contact 1-Wire® bus. The communication follows the standard 1-Wire protocol with the registration number acting as the node address in the case of a multidevice 1-Wire network.ApplicationsAccessory/PCB IdentificationIdentification and authentication of consumablesInk and Toner Print Cartridge IdentificationIntellectual Property, License ManagementSensor Calibration and AuthenticationSystem Programmable Feature Control

The DS3231 is a low-cost, extremely accurate I²C real-time clock (RTC) with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input, and maintains accurate timekeeping when main power to the device is interrupted. The integration of the crystal resonator enhances the long-term accuracy of the device as well as reduces the piece-part count in a manufacturing line. The DS3231 is available in commercial and industrial temperature ranges, and is offered in a 16-pin, 300-mil SO package.The RTC maintains seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an active-low AM/PM indicator. Two programmable time-of-day alarms and a programmable square-wave output are provided. Address and data are transferred serially through an I²C bidirectional bus.A precision temperature-compensated voltage reference and comparator circuit monitors the status of VCC to detect power failures, to provide a reset output, and to automatically switch to the backup supply when necessary. Additionally, the active-low RST pin is monitored as a pushbutton input for generating a µP reset.ApplicationsGlobal Positioning Systems (GPS)ServersTelematicsUtility Power Meters