PCIe Gen4/5/6 Class Low Jitter LC PLL on TSMC CLN7FF

Overview

The PCIe Gen5 REF PLL addresses stringent performance requirements in high-speed serial link applications that support the PCI Express Gen4 and Gen5 serial bus standard where SRIS (Separate RefClk Independent Spread-spectrum clock generation) is required. This SSCG PLL is designed for digital logic processes and uses robust design techniques to work in noisy SoC environments.

The PLL macro is implemented in Analog Bits’proprietary architecture that uses core and 1.8V IO devices.

With all components integrated, jitter performance and standby-power are significantly improved.

SSCG PLL Operational Range Description Symbol Min Typ Max Units Input Frequency FREF 24 25 38.4 MHz Input Frequency in Bypass Mode fBYPASS 100 MHz VCO Frequency FVCO 4800 MHz Output Frequency FOUT 5 100 2400 MHz Output Duty Cycle tDO 48 52 % Lock Time tLOCK 10 µs Reset Time tRESET 1 µs PLLOUT Random Filtered Phase Jitter RJPO,FILT 0.081 ps-RMS PLLOUT Random unfiltered Phase Jitter RJPO 1.03 ps-RMS Modulation Frequency FM 30 33 kHz Modulation Depth (down-spread) DMD -5000 0 ppm Area A 0.086 sq. mm Total Power IDD 12 20 mW Output Load CL 100 fF Operational Voltage (Digital) VDIG 0.675 0.75 0.825 V Operational Voltage (Analog) VANA 1.62 1.8 1.98 V Operational Temperature TOP -40 25 125 C Table 1: SSCG PLL Operational Range

Key Features

  • High performance design emphasis for meeting low jitter requirements in PCIe Gen4 & Gen5 applications
  • Implemented with Analog Bits’ proprietary LC architecture
  • Low power consumption
  • Spread Spectrum Clock Generation (SSCG) and tracking capability
  • Excellent jitter performance with optimized noise rejection
  • Calibration code and Bandgap voltage observability (for debug)
  • Requires no additional on-chip components or band-gaps, minimizing power consumption

Technical Specifications

Foundry, Node
TSMC CLN7FF
TSMC
Pre-Silicon: 7nm
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Semiconductor IP