Timers & Support Products General Purp Single

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 DS1747 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 512k x 8 nonvolatile static RAM. User access to all registers within the DS1747 is accomplished with a byte-wide interface as shown in Figure 1. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour binary-coded decimal (BCD) format. Corrections for the date of each month and leap year are made automatically. The RTC clock registers are double buffered to avoid access of incorrect data that can occur during clock update cycles. The double-buffered system also prevents time loss as the timekeeping countdown continues unabated by access to time register data. The DS1747 also contains its own power-fail circuitry that deselects the device when the VCC supply is in an out-of-tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low VCC as errant access and update cycles are avoided.

The DS17285, DS17485, DS17885, DS17287, DS17487, and DS17887 real-time clocks (RTCs) are designed to be successors to the industry-standard DS12885 and DS12887. The DS17285, DS17485, and DS17885 (hereafter referred to as the DS17x85) provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed NV SRAM. The DS17x85 also incorporates a number of enhanced functions including a silicon serial number, power-on/off control circuitry, and 2K, 4K, or 8Kbytes of battery-backed NV SRAM. The DS17287, DS17487, and DS17887 (hereafter referred to as the DS17x87) integrate a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS17x85 and DS17x87 power-control circuitry allows the system to be poweredon by an external stimulus such as a keyboard or by a time-and-date (wake-up) alarm. The active-low PWR output pin is triggered by one or either of these events, and is used to turn on an external power supply. The active-low PWR pin is under software control, so that when a task is complete, the system power can then be shut down.For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. It also operates in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to a backup supply. A lithium coin cell battery can be connected to the VBAT input pin on the DS17x85 to maintain time and date operation when primary power is absent. The DS17x85 and DS17x87 include a VBAUX input used to power auxiliary functions such as active-low PWR control. The device is accessed through a multiplexed byte-wide interface.ApplicationsEmbedded SystemsNetwork Hubs, Bridges, and RoutersSecurity SystemsUtility Meters

The DS17285, DS17485, DS17885, DS17287, DS17487, and DS17887 real-time clocks (RTCs) are designed to be successors to the industry-standard DS12885 and DS12887. The DS17285, DS17485, and DS17885 (hereafter referred to as the DS17x85) provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed NV SRAM. The DS17x85 also incorporates a number of enhanced functions including a silicon serial number, power-on/off control circuitry, and 2K, 4K, or 8Kbytes of battery-backed NV SRAM. The DS17287, DS17487, and DS17887 (hereafter referred to as the DS17x87) integrate a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS17x85 and DS17x87 power-control circuitry allows the system to be poweredon by an external stimulus such as a keyboard or by a time-and-date (wake-up) alarm. The active-low PWR output pin is triggered by one or either of these events, and is used to turn on an external power supply. The active-low PWR pin is under software control, so that when a task is complete, the system power can then be shut down.For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. It also operates in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to a backup supply. A lithium coin cell battery can be connected to the VBAT input pin on the DS17x85 to maintain time and date operation when primary power is absent. The DS17x85 and DS17x87 include a VBAUX input used to power auxiliary functions such as active-low PWR control. The device is accessed through a multiplexed byte-wide interface.ApplicationsEmbedded SystemsNetwork Hubs, Bridges, and RoutersSecurity SystemsUtility Meters

Real Time Clock Low Power High Stability +/-5 ppm -40 - +85C IC Real Time Clock 3.2 x 2.5 mm

IC Output 24-QFN (4x4)

Clock Generators & Support Products VersaClock 5 LP Program CLK

SI53154 Clock Buffer Timing Evaluation Board

Clock Generators & Support Products 4-output, any frequency (< 200 MHz), any output, clock generator (reference input)