Fig.1 Functional Block Diagram
The temperature stable and broadband ASNT1122-KMC SiGe IC is a high isolation selector switch that is intended for use in high-speed measurement / test equipment. The part routes one of 4 single-ended CML inputs (d0p, d1p, d2p, d3p) to its differential CML output outp/outn while effectively blocking the other data inputs with high isolation. Selection of a specific data input is controlled by two digital control signals sel1 and sel2 in accordance with Table 1 found within the part’s dataseet. The duty cycle of the output signal is controlled by an external analog voltage vbias.
The part’s I/Os support CML logic interfaces with on chip 50Ω termination to vcc, and it may be used differentially, AC/DC coupled, single-ended or in any combination. In the first mode, the input signal’s common mode voltage should comply with the specifications shown in the electrical characteristics table within the part’s datasheet. In the second mode, the input termination provides the required common mode voltage automatically. Differential DC signaling is recommended for optimal performance, and the part operates on a single +3.3V or -3.3V power supply.