| 摘要 |
The present invention provides an input receiver in a differential amplifier or modified differential amplifier configuration which adjusts the input high and low voltage signals compatible with multiple input/output (I/O) interfaces, including transistor-transistor logic (TTL), Low Voltage TTL (LVTTL), and Stub Series Terminated Logic (SSTL) interfaces. Transistors in a differential amplifier or modified differential amplifier configuration that receive a reference-voltage signal and receiver-enable signal are adjusted in accordance to the input high signal and input low signal requirements for a selected type of interface, while other transistors remain at a relatively constant voltage. Once a particular type of interface has been selected, the gate voltages for the transistors that receive the reference-voltage and receiver-enable signals remain relatively constant. The switching speed of an input receiver is not adversely affected by the additional load of non-operational FETs for one or more of the I/O interface types due to the supply of constant gate voltages to the transistors.
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