Error (175001): Could not place LC_PLL_CHANNEL_CLUSTER - Error (175001): Could not place LC_PLL_CHANNEL_CLUSTER Description If you implement the Low Latency PHY with channel bonding and fb_compensation mode in Quartus ® II 12.1 for Stratix® V devices, and need to reconfigure the Tx PLL, you may get the fitter error above. Resolution You should add XCVR_TX_PLL_RECONFIG_GROUP assignments for the tx_pll of each channel to enable Tx PLL merging. You can find the tx_pll name in post-synthesis results. Related Articles Have there been any changes in Quartus II 12.1 when merging Transceiver TX PLLs if PLL/CDR Reconfiguration has been enabled in Stratix V GX devices? Custom Fields values: ['novalue'] Troubleshooting novalue False ['novalue'] ['FPGA Dev Tools Quartus II Software'] novalue 12.1 ['Stratix® V GS FPGA', 'Stratix® V GT FPGA', 'Stratix® V GX FPGA'] ['novalue'] ['novalue'] ['novalue']