Low Voltage Transistor-Transistor Logic (LVTTL) - Low Voltage Transistor-Transistor Logic (LVTTL) - UG861

LVTTL is a general-purpose EIA/JESD standard for 3.3V applications that uses a single-ended CMOS input buffer and a push-pull output buffer. This standard requires a 3.3V output source voltage (V_CCO), but does not require the use of a reference voltage (V_REF ) or a termination voltage (V_TT). This standard is defined by JEDEC (JESD 8C.01).

Sample circuits illustrating both unidirectional and bidirectional LVTTL termination techniques are shown in the following figures. These two diagrams show examples of source-series and parallel terminated topologies.

The following figure shows unidirectional terminated topologies.

The following figure shows a bidirectional, parallel-terminated topology.

The following table details the allowed attributes that can be applied to the LVTTL I/O standard. This standard is only available in the HD I/O banks. Support is implied for primitives that are derivatives of the primitives listed in the following table (for example: *_DIFF_OUT, *_DCIEN, *_IBUFDISABLE, or *_INTERMDISABLE). Refer to SelectIO IOB Interface Primitives for all supported derivatives.