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Renesas Electronics Corporation

Renesas’ Timing product portfolio has been acquired by SiTime.

Datasheets, documentation, and sample orders remain available on Renesas.com through late 2026. For new designs, purchasing, support, and product inquiries, visit SiTime.com or send an email to [email protected]. Full transition to SiTime is expected by late 2026.

Features

  • Fourth generation FemtoClock® Next Generation (NG) technology
  • One differential 3.3V LVPECL output and one LVCMOS/LVTTL output
  • Crystal oscillator interface designed for a 25MHz parallel resonant crystal
  • A 25MHz crystal generates output frequencies of: 156.25MHz and 125MHz
  • VCO frequency: 625MHz
  • RMS Phase Jitter @ 156.25MHz, (12kHz – 20MHz) using a 25MHz crystal: 0.33ps (typical)
  • RMS Phase Jitter @ 125MHz, (12kHz – 20MHz) using a 25MHz crystal: 0.39ps (typical)
  • Power supply noise rejection PSNR: -60dB (typical)
  • Full 3.3V supply mode
  • 0°C to 70°C ambient operating temperature
  • Available in lead-free (RoHS 6) package

Description

The 843N252-45 is a 1 LVPECL and 1 LVCMOS output synthesizer optimized to generate Ethernet reference clock frequencies. The device uses our fourth generation FemtoClock ® NG technology for an optimum of high clock frequency and low phase noise performance, combined with low power consumption and high power supply noise rejection. Using a 25MHz parallel resonant crystal, the following frequencies can be generated: 156.25MHz and 125MHz. With a very low phase noise VCO it is targeted to achieve 0.4ps or lower typical rms phase jitter, easily meeting Ethernet jitter requirements. The 843N252-45 is packaged in a small 16-pin TSSOP package.

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