One of the major physics goals of the sPHENIX experiment at RHIC
is to major the Upsilon states with 100MeV mass resolution. In order to
achieve this resolution, a Time Projection Chamber (TPC) was proposed
for momentum measurements of electrons and hadrons. The TPC does
not have a gating grid similarly to the ALICE TPC case and therefore
capable for handing the collision rate of up to a few hundreds KHz.
In turn, the charge has to be readout continuously. The readout
electronics was newly designed to meet this requirement. The signal is
readout by 624 Frontend cards that have 8 SAMPA v5 chips, the new
version of the one employed for ALICE TPC, and sent to a backend
electronics, FELIX PCI card, designed for ATLAS experiment. The data
rate from the whole TPC may reach as much as 1.4Tbps. We will show
the readout scheme for the TPC and the performance from the prototype
boards as well as the data reduction scheme.