The ISO7421 and ISO7421M provide galvanic isolation up to 2.5 kVrms for 1 minute per UL. These digital isolators have two isolated channels with bidirectional channel configuration. Each isolation channel has a logic input and output buffer separated by a silicon dioxide (SiO2) insulation barrier. Used in conjunction with isolated power supplies, these devices prevent noise currents on a data bus or other circuit from entering the local ground and interfering with or damaging sensitive circuitry. The devices have TTL input thresholds and require two supply voltages from 3 V to 5.5 V, or any combination. All inputs are 5-V tolerant when supplied from a 3-V supply. ISO7421