Multiple-Output Clock Generators Exceed Ethernet Requirements

The MAX3627/MAX3629 low-jitter clock generators serve high-speed networking applications. The MAX3627 has seven LVDS outputs and one LVCMOS output, while the MAX3629 has five LVDS outputs and three LVCMOS outputs. Both generators utilize a low-noise crystal oscillator and PLL architecture to generate high-frequency (312.5 MHz), ultra-low-jitter (0.14-ps RMS) clock signals from a 25-MHz crystal or reference clock input. The devices simultaneously generate two pin-selectable frequencies for both Ethernet port clocking and MAC clocking. This function eliminates the need for an expensive high-frequency oscillator and a fanout buffer, saving board space and cost. With excellent power-supply noise rejection (PSNR), both parts minimize jitter degradation in noisy power-supply environments. The MAX3627/MAX3629 are ideal for Ethernet interface applications, such as enterprise switches and routers, and other high-speed data-communication systems that require a low-jitter Ethernet frequency. Both devices are fully specified over the 0°C to +70°C commercial temperature range, and operate from a 3.3-V ±5% power supply. They are available in lead-free, 32-pin TQFN packages with prices starting at $8.80 in 1000-piece quantities. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.