  We describe the fundamental trade-offs in engineering the mobility, current
saturation and ON- OFF ratios in graphene transistors. Surprisingly, the
trade-offs arise solely from an asymptotic constraint on the high energy
bandstructure and independent of scattering processes. This places graphite
derivatives (bulk monolayer graphene, uniaxially strained graphene nanoribbons,
carbon nanotubes and bilayer graphene) on the same 3-parameter
mobility-bandgap-scattering length ({\mu} - Egap -{\lambda}) plot, proximal to
other semiconductors. In addition to this low-bias trade-off, the high bias
current bears signatures of the underlying saturation mechanism, arising
through phonon scattering or {\Gamma}-point suppressed density of states
opening bandgap.
