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 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

The MAX9310A is a fast, low-skew 1:5 differential driver with selectable LVPECL inputs and LVDS outputs, designed for clock distribution applications. This device features an ultra-low propagation delay of 340ps with 48mA of supply current.The MAX9310A operates from a 3V to 3.6V power supply for use in 3.3V systems. A 2:1 input multiplexer is used to select one of two differential inputs. The input selection is controlled through the CLKSEL pin.This device features a synchronous enable function. The MAX9310A LVPECL inputs can be driven by either a differential or single-ended signal. A VBB reference voltage output is provided for use with single-ended inputs. The device can also accept differential HSTL signals.The MAX9310A is offered in a space-saving 20-pin TSSOP package and operates over the extended temperature range from -40°C to +85°C.ApplicationsAutomated Test Equipment (ATE)Central Office Backplane Clock DistributionData and Clock Driver and BufferDSLAMWireless Base Stations

The MAX9320B low-skew, 1-to-2 differential driver is designed for clock and data distribution. The input is reproduced at two differential outputs. The differential input can be adapted to accept single-ended inputs by applying an external reference voltage.The MAX9320B features ultra-low propagation delay (208ps), part-to-part skew (20ps), and output-to-output skew (6ps) with 30mA maximum supply current, making this device ideal for clock distribution. For interfacing to differential PECL and LVPECL signals, this device operates over a +3.0V to +5.5V supply range, allowing high-performance clock or data distribution in systems with a nominal 3.3V or 5V supply. For differential ECL and LVECL operation, this device operates from a -3.0V to -5.5V supply.The MAX9320B is offered in industry-standard 8-pin TSSOP and SO packages.ApplicationsLow-Jitter Data RepeaterPrecision Clock DistributionProtection Switching

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 DS1124 is an 8-bit programmable timing element similar in function to the DS1021-25. The 256-delay intervals are programmed by using a 3-wire serial interface. With a 0.25ns step size, the DS1124 can provide a delay time from 20ns up to 84ns with an integral nonlinearity of ±3ns.ApplicationsDigital Test EquipmentDigital Video ProjectionLCD TelevisionsSignal Generators and AnalyzersTelecommunications

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 LTC6948 is a high performance, low noise, 6.39GHz phase-locked loop (PLL) with a fully integrated VCO, including a reference divider, phase-frequency detector (PFD), ultralow noise charge pump, fractional feedback divider, and VCO output divider.The fractional divider uses an advanced, 4th order ΔΣ modulator which provides exceptionally low spurious levels. This allows wide loop bandwidths, producing extremely low integrated phase noise values.The programmable VCO output divider, with a range of 1 through 6, extends the output frequency range.Applications Wireless Basestations (LTE, WiMAX, W-CDMA, PCS) Microwave Data Links Military and Secure Radio Test and Measurement

The LTC6948 is a high performance, low noise, 6.39GHz phase-locked loop (PLL) with a fully integrated VCO, including a reference divider, phase-frequency detector (PFD), ultralow noise charge pump, fractional feedback divider, and VCO output divider.The fractional divider uses an advanced, 4th order ΔΣ modulator which provides exceptionally low spurious levels. This allows wide loop bandwidths, producing extremely low integrated phase noise values.The programmable VCO output divider, with a range of 1 through 6, extends the output frequency range.Applications Wireless Basestations (LTE, WiMAX, W-CDMA, PCS) Microwave Data Links Military and Secure Radio Test and Measurement

The LTC6954 is a family of very low phase noise clock distribution parts. Each part has three outputs and each output has an individually programmable frequency divider and delay. There are four members of the family, differing in their output logic signal type:LTC6954-1: Three LVPECL outputsLTC6954-2: Two LVPECL and one LVDS/CMOS outputsLTC6954-3: One LVPECL and two LVDS/CMOS outputsLTC6954-4: Three LVDS/CMOS outputsEach output is individually programmable to divide the input frequency by any integer from 1 to 63, and to delay each output by 0 to 63 input clock cycles. The output duty cycle is always 50%, regardless of the divide number. The LVDS/CMOS outputs are jumper selectable via the OUTxSEL pins to provide either an LVDS logic output or a CMOS logic output.The LTC6954 also features Linear Technology’s EZSync system for perfect clock synchronization and alignment every time.All device settings are controlled through an SPI-compatible serial port.Applications Clocking High Speed, High Resolution ADCs, DACs and Data Acquisition Systems Low Jitter Clock Distribution