The DS1340 is a real-time clock (RTC)/calendar that is pin compatible and functionally equivalent to the ST M41T00, including the software clock calibration. The device additionally provides trickle-charge capability on the VBACKUP pin, a lower timekeeping voltage, and an oscillator STOP flag. Block access of the register map is identical to the ST device. Two additional registers, which are accessed individually, are required for the trickle charger and flag. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. A built-in power-sense circuit detects power failures and automatically switches to the backup supply. The device is programmed serially through an I²C bidirectional bus.ApplicationsMedical EquipmentPoint-of-Sale EquipmentPortable InstrumentationTelecommunications

The DS1374 is a 32-bit binary counter designed to continuously count time in seconds. An additional counter generates a periodic alarm or serves as a watchdog timer. If disabled, this counter can be used as 3 bytes of nonvolatile (NV) RAM. Separate output pins are provided for an interrupt and a square wave at one of four selectable frequencies. A precision temperature-compensated reference and comparator circuit monitor the status of VCC to detect power failures, provide a reset output, and automatically switch to the backup supply when necessary.Additionally, the reset pin is monitored as a pushbutton input for externally generating a reset. The device is programmed serially through an I²C serial interface.ApplicationsMedical EquipmentPoint-of-Sale EquipmentPortable InstrumentationTelecommunications

The DS1501/DS1511 are full-function, year 2000-compliant real-time clock/calendars (RTCs) with an RTC alarm, watchdog timer, power-on reset, battery monitors, 256 bytes NV SRAM, and a 32.768kHz output. User access to all registers within the DS1501/DS1511 is accomplished with a byte-wide interface, as shown in Figure 8. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour binary-coded decimal (BCD) format. Corrections for day of month and leap year are made automatically.ApplicationsBattery-Backed SystemsConsumer ElectronicsOffice EquipmentRemote SystemsTelecom Switches

The DS3232 is a low-cost temperature-compensated crystal oscillator (TCXO) with a very accurate, temperature-compensated, integrated real-time clock (RTC) and236 bytes of battery-backed SRAM. Additionally, the DS3232 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 DS3232 is available in commercial and industrial temperature ranges, and is offered in an industry-standard 20-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. Theclock 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.ApplicationsGPSServersTelematicsUtility Power Meters

The Maxim ICM7555 and ICM7556 are respectively singleand dual general-purpose RC timers capable of generatingaccurate time delays or frequencies. The primaryfeature is an extremely low supply current, making thisdevice ideal for battery-powered systems. Additional featuresinclude low THRESHOLD, active-low TRIGGER, and active-low RESETcurrents, a wide operating supply voltage range, andimproved performance at high frequencies.These CMOS low-power devices offer significant performanceadvantages over the standard 555 and 556 bipolartimers. Low-power consumption, combined with the virtuallynonexistent current spike during output transitions, makethese timers the optimal solution in many applications.ApplicationsMissing Pulse DetectorPrecision TimingPulse GeneratorPulse Position ModulationPulse-Width ModulationSequential TimingTime Delay Generation

The DS1100 series delay lines have five equally spaced taps providing delays from 4ns to 500ns. These devices are offered in surface-mount packages to save PCB area. Low cost and superior reliability over hybrid technology is achieved by the combination of a 100% silicon delay line and industry-standard µMAX® and SO packaging. The DS1100 5-tap silicon delay line reproduces the input-logic state at the output after a fixed delay as specified by the extension of the part number after the dash. The DS1100 is designed to reproduce both leading and trailing edges with equal precision. Each tap can drive up to 10 74LS loads.Maxim can customize standard products to meet special needs.

The DS1110 delay line is an improved replacement for the DS1010. It has ten equally spaced taps providing delays from 5ns to 500ns. The devices are offered in a standard 16-pin SO, or 14-pin TSSOP. The DS1110 series delay lines provide a nominal accuracy of ±5% or ±2ns, whichever is greater, at 5V and +25°C. The DS1110 reproduces the input logic state at the tap 10 output after a fixed delay as specified by the dash number extension of the part number. The DS1110 is designed to produce both leading- and trailing-edge delays with equal precision. Each tap is capable of driving up to ten 74LS type loads. Dallas Semiconductor can customize standard products to meet special needs.ApplicationsAutomated Test Equipment (ATE)Communication SystemsMedical DevicesPC Peripheral Devices

The DS1244 256k NV SRAM with a Phantom clock is a fully static nonvolatile RAM (NV SRAM) (organized as 32k words by 8 bits) with a built-in real-time clock. The DS1244 has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock.The phantom clock provides timekeeping information for hundredths of seconds, seconds, minutes, hours, days, date, months, and years. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The phantom clock operates in either 24-hour or 12-hour format with an AM/PM indicator.

The DS1248 1024K NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 128K words by 8 bits) with a built-in real-time clock. The DS1248 has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and writes protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock.

The DS1305 serial alarm real-time clock provides a full binary coded decimal (BCD) clock calendar that is accessed by a simple serial interface. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date 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 AM/PM indicator. In addition, 96 bytes of NV RAM are provided for data storage. The DS1305 will maintain the time and date, provided the oscillator is enabled, as long as at least one supply is at a valid level. An interface logic power-supply input pin (VCCIF) allows the DS1305 to drive SDO and active-low PF pins to a level that is compatible with the interface logic. This allows an easy interface to 3V logic in mixed supply systems.The DS1305 offers dual-power supplies as well as a battery input pin. The dual power supplies support a programmable trickle charge circuit that allows a rechargeable energy source (such as a super cap or rechargeable battery) to be used for a backup supply. The VBAT pin allows the device to be backed up by a non-rechargeable battery. The DS1305 is fully operational from 2.0V to 5.5V.Two programmable time-of-day alarms are provided by the DS1305. Each alarm can generate an interrupt on a programmable combination of seconds, minutes, hours, and day. 'Don't care' states can be inserted into one or more fields if it is desired for them to be ignored for the alarm condition. The time-of-day alarms can be programmed to assert two different interrupt outputs or to assert one common interrupt output. Both interrupt outputs operate when the device is powered by VCC1, VCC2, or VBAT.The DS1305 supports direct serial peripheral interface SPI™ to serial data ports or standard 3-wire interface. A straightforward address and data format is implemented in which data transfers can occur 1 byte at a time or in multiple-byte-Burst Mode®.