SY89425

DUAL SONET OC-12 CLOCK SYNTHESIZER FEATURES s Two independently-powered 622.08MHz clock sources one chip s Differential PECL outputs s TTL/CMOS compatible inputs s SONET compliant jitter performance (≤0.01UI) s Choice of three reference frequencies for each PLL s Only 395mW per PLL (typ) s Complies with Bellcore, CCITT and ANSI standards s Single +5 volt power supply s Fully compatible with industry standard 10KH I/O levels s Available in 28-pin PLCC package ClockWorks™ SY89425 DESCRIPTION Micrel-Synergy's SY89425 Dual Phase Locked Loop (PLL) consists of two totally separate, SONET compliant 622.08MHz clock generators on one chip. The user may select to power both PLLs or PLL A only. Each PLL produces a low-jitter OC-12/STS-12 clock rate from an input reference clock of 38.88, 51.84, or 77.76MHz. When using both PLLs, it is not necessary that they share a common reference clock (e.g., PLL A may operate from an STS-1 reference of 51.84MHz, while PLL B operates from an OC-3/STS-3 reference of 77.76MHz). The SY89425 operates from a single +5 volt supply, and requires only a simple series RC loop filter for each PLL. Coupling Micrel-Synergy's advanced PLL technology with our proprietary ASSET™ bipolar process has produced a clock generator IC which exceeds applicable Bellcore and ANSI specifications, while setting a new standard for performance and flexibility. TYPICAL APPLICATION +5V +5V PIN CONFIGURATION FLTRAN FLTRAP RSTA VCCA GND GND RFCKA (TTL) VCCA VCCOA RSTA (TTL...