Intersil offers standard '555 type counter/timers as well as high frequency digital synthesizers. Intersil’s family of Real Time Clock products offer a wide variety of useful industry-standard functions and features covering basic low-cost clock and calendar RTCs, feature-rich RTCs including supervisory functions and EEPROM memory for system personality data, as well as high-accuracy 3-in1 RTC modules which integrate and RTC, 32kHz crystal, and onboard temperature sensor.
Brandywine Communications offers a complete line of time and frequency systems - from complete timing systems (Master Clocks), to Network (NTP Servers) and IEEE-1588 Precision Time Protocol (PTP) Time Servers, from GPS clocks to time displays. Brandywine offers ruggedized time and frequency standards for military use, high quantities and quick delivery of systems for satellite ground stations, and cost effective systems for infrastructure projects such as airports and rail terminals.
Microchip can complete your entire clock tree including: '555 counter/timers, Oscillators - MEMs based, small size and low power, Clock Generators - programmable, low jitter, low power, VCXO's, Clock Distribution - 2 to 22 outputs, up to 7 Ghz, muxes, delay lines, level translators, Real Time Clocks - low-cost Real-Time Clock/Calendar devices with battery backup capability, digital trimming along with onboard EEPROM and SRAM memory.