An I/O standard with a single-ended signal, input/output (V_CCIO) voltages of 3.3 V and input/output buffers of 3.3-V/2.5-V TTL. The LVTTL I/O standard is supported by all Altera^® devices supported by the Quartus^® II software.

The LVCMOS and LVTTL I/O standards are the default standards and are treated as the same standard by ACEX^® 1K, APEX^™ 20K, FLEX^® 6000, FLEX 10KE, MAX^® 3000A, MAX 7000AE, and MAX 7000B devices, and are treated as separate standards by APEX 20KC, APEX 20KE, APEX^™ II, ARM^®-based Excalibur^™, Cyclone^™, Mercury^™, Stratix^™, and Stratix^™ GX devices.