The new receiver IC reduces the area taken up by the circuitry of PHS phones, its high level of integration cutting the number of circuit elements to almost half that found in current state-of-the-art handy phones. This is achieved by utilization of silicon BiCMOS processing of a direct conversion receiver (DCR) chip. The DCR chip requires less external circuitry and has lower manufacturing costs than the GaAs super heterodine chip used in PHS receivers now under developemnt. The new IC integrates such circuits as a low noise amplifier, frequency converter, channel selection filter circuit and a variable gain amplifier on a single chip.

Digital mobile telephone systems are enjoying rapid growth, and this is promoting interest in developing more affordable systems. In Japan, the new PHS digital mobile telephone systems, which use the 1.9GHz frequency band, are now completing system development. Commercial services are expected to start this July. PHS transceivers must be small, a requirement promoting demand for small semiconductor-based components. Toshiba's new receiver IC provides a solution with technologies that can be applied to diverse mobile information and communications equipment.

The new technologies for the receiver IC will be announced on Thursday 16th, February, at the International Solid State Circuits Conference '95, in San Francisco.

<Main features>

1. Direct conversion receiver (DCR) chip: The DCR chip requires fewer external components and has no need of IF filters. DCR chips are already used in constant-amplitude modulation systems such as pagers, but they have not been incorporated in QPSK* systems, such as PHS, as they tends to generate distortions in the frequency converter stage and cause deterioration in receiver sensitivity. Toshiba's new DCR chip improves circuit and lowers distortion, allowing incorporation in PHSs.

2. BiCMOS process: Current receiver ICs for PHS are based on costly GaAs processing. Silicon offers a cheaper alternative, promoting demand for alternative silicon-based ICs. Toshiba has made use of its expertise in fine BiCMOS processing technology to develop a single-chip IC. The reduction of parts counts resulting from direct conversion and the more cost-attractive silicon processing will contribute to reductions in the size and cost of digital mobile communication equipment and systems.

   * Note: QPSK (Quadrature Phase Shift Keying) is a phase modulation that shifts the radio frequency (RF) signal phase by 90 degrees. The signal includes a frequency modulation (FM) component and amplitude modulation (AM) component. The combination of the two components makes it possible to transmit more digital information at a faster rate.

   <Specifications>

    
   Power supply voltage:    2.7V  
   Power consumption:       165mW  
   Chip size:               5.1 mm x 5.1mm  
   Dynamic range:           95dB