Fig. 1 Functional Block Diagram
ASNT1121-KMM is a low power and high-speed digital 4 to 1 serializer-multiplexer (MUX) that functions seamlessly over data rates (fbit) ranging from DC to its maximum frequency. The main function of the part is to multiplex 4 parallel differential CML data signals d0p/d0n, d1p/d1n, d2p/d2n, d3p/d3n running at a bit rate of fbit/4 into a high speed serial bit stream qp/qn running at a bit rate of fbit. Differential or single-ended full-rate clock cep/cen must be provided by an external source for the part to function properly.
The serialized data words qp/qn and the clock divided-by-4 signal c4op/c4on are transmitted through CML output interfaces. The clock and data outputs are phase-matched to each other resulting in a very little relative skew over the operating temperature range of the device. All I/O stages are back terminated with on-chip 50Ω resistors and may be used in either DC or AC coupling modes. In the first mode, the input signal’s common mode voltage should comply with 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 uses a single +3.3V or -3.3V power supply.