Low Voltage CMOS (LVCMOS) - Low Voltage CMOS (LVCMOS) - UG861

LVCMOS is a widely used switching standard implemented in CMOS transistors. These standards include JESD8-12A.01, JESD8-11A.01, JESD8-7A, JESD8-5A.01, and JESD8C.01 (https://www.jedec.org). The LVCMOS standards supported in Spartan UltraScale+ devices are: LVCMOS10, LVCMOS11, LVCMOS12, LVCMOS135, LVCMOS15, LVCMOS18, LVCMOS25, and LVCMOS33. These LVCMOS buffers are intended to support lower performance needs in a variety of bank voltage options as described in the numeric portion of the IOSTANDARD name, that is, LVCMOS18 is intended to operate 1.8 V bank voltages that require full swing signaling. Only a partial combination of supported voltage levels are available in each bank type (HD, HP, and XP5IO I/O banks).

Sample circuits illustrating both unidirectional and bidirectional LVCMOS 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 LVCMOS33 and LVCMOS25 I/O standards. These standards are 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.

The following table details the allowed attributes that can be applied to the LVCMOS18 I/O standard. This standard is available in both the HD and HP I/O banks. For MOBILE DDR applications, the LVCMOS18 I/O standard is used with an 8 mA unterminated drive. 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.

The following table details the allowed attributes that can be applied to the LVCMOS15 I/O standard. This standard is available in both the HD and HP 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.

The following table details the allowed attributes that can be applied to the LVCMOS12 I/O standard. This standard is available in both the HD and HP 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.

The following table details the allowed attributes that can be applied to the LVCMOS12 I/O standard. This standard is available in both the HD and HP 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.