A 2.7 V 2.5 GHz bipolar chipset for digital wireless communication

The chipset targets primarily the digital cordless european telecommunication (DECT) standard, that applies to business as well as to the consumer market. The transceiver chipset for digital data transmission is realized on the 25 GHz bipolar Siemens B6HF process. The transmitter IC integrates the complete synthesizer including PLL, VCOs, frequency doubler, supply voltage regulation and supporting switching functions. Due to the open-loop architecture, the input impedance variation of the switched power amplifier results in frequency deviation of the VCO caused by load pulling. The required isolation can not be achieved within a single IC package. Previous solutions use an external discrete buffer stage. To increase the integration level, the buffer amplifier has been realized on the RX-IC. The advantage of this configuration is increased isolation due to the fully-differential setup. The chipset architecture is suitable for FSK digital mobile radio portable and base stations, especially cordless phone system from 1.6 GHz up to 2.5 GHz including DECT, wireless LAN, wireless local loop, 2.4 GHz ISM band frequency hopping system or any other system using FSK modulation. The TX design is optimized with respect to power supply, low current consumption, frequency stability and phase noise, whereas the RX-design is optimized for sensitivity and input intercept point simultaneously.