U2270B是一种典型的发射频率为125 kHz的非接触性IC卡射频基站芯片。 The U2270B is an IC for IDIC[ *) read/write base stations in contactless identification and immo-bilizer systems. The IC incorporates the energy-transfer circuit to supply the transponder. It consists of an on-chip power supply, an oscillator and a coil driver optimized for automotivespecific distances. It also includes all signal-processing circuits which are necessary to form the small input signal into a microcontroller-compatible signal. The U2270B is well suited to perform read operations with e5530-GT and TK5530-PP transponders and also performs read/write operations with TK5550-PP and TK5560-PP transponders.