DEPFET Pixel sensor matrices consist of regular arrangements of DEPFETs. They are
read out sequentially by enabling individual gate rows so that the currents in the
drain columns reflect the pixel charge. Specialized chips are required to apply
voltage steps of up to 10V to gate- and clear rows. The radiation tolerant switcher3
chip has been developed for that purpose. It contains 128 channels, a flexible
sequencer and relies on bump bonding. A prototype for the latest drain readout
architecture is also presented.