I don't know about the VHC family, buy the LVC1G family can drive 24 mA. My interface boards for connecting the LPFRS/LPRO or the TS-RFS to my BNC/SMA connector board has a PICDIV for making a 1PPS signal and uses a 74LVC1G125 to buffer it. Also my PRS10 interface uses one to buffer the 1PPS output.