A key attribute of the Certus 28nm IO library is its ability to detect and dynamically adjust to a VDDIO supply of 1.8V or 3.3V during system operation. The GPIO cell set can be configured as input, output, open-source, or open-drain with an optional internal 60K ohm pull-up or pull-down resistor. Digital cells for 25MHz, 75MHz, and 150MHz allow optimization across SSO currents & power. ESD protection for VDDIO, VREF and core VDD supplies is constructed in an aggressive footprint. The library also features 5V I2C open-drain (fail-safe), a 5V OTP programming cell, and 1.8V & 3.3V analog cells. 1.8V LVDS and 3.3V, 5V tolerant fail-safe HDMI protection blocks with low-cap signal pads are also available. The library is enriched with feed-through, filler, transition and domain-break cells to allow for flexible pad ring construction.