HR |
HP |
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Available |
N/A |
Low voltage TTL (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) [Ref 7] .
Sample circuits illustrating both unidirectional and bidirectional LVTTL termination techniques are shown in This Figure and This Figure . These two diagrams show examples of source-series and parallel terminated topologies.
This Figure shows unidirectional terminated topologies.
This Figure shows a bidirectional, parallel-terminated topology.
Table: Allowed Attributes for the LVTTL I/O Standards details the allowed attributes that can be applied to the LVTTL I/O standard. This standard is only available in the HR I/O banks. Support is implied for primitives that are derivatives of the primitives listed in Table: Allowed Attributes for the LVTTL I/O Standards (for example: *_DIFF_OUT, *_DCIEN, *_IBUFDISABLE, or *_INTERMDISABLE). Refer to the SelectIO Interface Primitives section for all supported derivatives.