Logic-level sensitive-gate TRIAC for 230 VAC loads
The STMicroelectronics T405-700B-TR is a single-channel logic-level sensitive-gate TRIAC rated for 700 V off-state voltage and 4 A RMS on-state current, housed in a surface-mount DPAK (TO-252) package. Its 5 mA maximum gate trigger current lets it switch directly from a microcontroller GPIO or optocoupler output without an intermediate driver transistor, simplifying the BOM on AC load-control boards. The -40°C to 125°C junction temperature range covers industrial environments — motor drives, outdoor telecom power supplies, and appliance control PCBs where ambient heat is a given.
Gate drive and hold current margins
Maximum gate trigger voltage is 1.3 V, so a logic output can drive it through a current-limiting resistor. The 10 mA maximum holding current means the TRIAC stays latched once triggered as long as the load current stays above that threshold.