时钟与计时

SI5345A-D-GMR

SI5345A-D-GMR - 10-Output Jitter Attenuator | Skyworks | 1028 MHz

The Skyworks (formerly Silicon Labs) SI5345A-D-GMR is a low-jitter, 10-output, any-frequency (<1028 MHz) clock multiplier and jitter attenuator housed in a 64-pin QFN exposed-pad package. The Si5345A variant combines fourth-generation DSPLL and MultiSynth fractional divider technologies to synthesize up to ten independent output clocks from a single reference input, while digital PLL bandwidth programming lets the designer trade reference spurs against in-band noise. A clock generator (or jitter attenuator) is a mixed-signal IC that produces one or more precise timing references from a lower-quality source clock. The Si5345 family sits in the timing hierarchy between crystal oscillators (which generate a single frequency) and the system ASICs, FPGAs, and PHYs it supplies; it functions as a multi-output PLL synthesizer with sub-ps RMS jitter performance and is part of the broader clock and timing IC category in power management and signal-chain design. Key features include 0.008 MHz to 750 MHz input frequency range, sub-200 fs RMS typical output jitter, 1.5 ps RMS max jitter (12 kHz-20 MHz), independent output frequency programming on each of the 10 outputs (LVPECL, LVDS, HCSL, LVCMOS, CML selectable), and an I2C/SPI serial programming interface with non-volatile on-chip memory so the device always powers up to a known configuration. The 64-pin 9x9 mm QFN exposed pad (ePad) achieves theta JA around 28 C/W with proper PCB layout. Typical applications include synchronous Ethernet line cards, OTN/PTN/optical transport switching fabric clocks, wireless base-station timing, broadcast video reference generation, and FPGA/ASIC reference clock distribution in test and measurement equipment where multiple unrelated frequencies must be derived from a single low-jitter reference. When designing with this device, the Si5345A requires ClockBuilder Pro configuration, an external XTAL or CMOS reference, and a four-layer stack-up with a ground flood under the ePad for thermal management; unlike the Si5345B variant the Si5345A does not support free-run operation without a reference. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that are not found in the Skyworks/SiLabs datasheet alone.