The Vishay TCLT1113 is a single-channel phototransistor optocoupler with a base terminal brought out, housed in a 5-lead 6-SOIC package. Its 5000Vrms isolation rating defines the reinforced insulation barrier for applications where galvanic separation between a low-voltage control side and a higher-voltage load side is mandatory — think motor-drive IGBT gate drives, industrial PLC digital inputs, or isolated DC-DC feedback loops. The transistor-with-base output gives you the option to bias the base for faster switching or to use it as a photodiode for analog feedback, which is a flexibility the standard phototransistor (base not pinned) does not offer.
CTR window and drive margin
The current transfer ratio is specified as 100% minimum and 200% maximum at a forward current of 10mA. That 2:1 spread means the designer sizes the load-side pull-up resistor for the worst-case minimum CTR to guarantee the output saturates, while the maximum ensures the driven logic input does not see excessive base drive. At 10mA LED current, a CTR of 100% delivers 10mA into the output transistor — enough to drive a standard TTL or CMOS gate through a 4.7kΩ pull-up to 5V. The 1.25V typical forward voltage at that current is standard for an infrared LED, so the series resistor on the input side is straightforward to calculate from the control-side supply rail.
Switching speed and output ratings
Rise and fall times are 3µs and 4.7µs typical, with turn-on and turn-off times of 6µs and 5µs respectively. That puts this part in the medium-speed class — fine for 10–100 kHz switching power-supply feedback or 19.2 kbps serial isolation, but not for high-speed digital isolator replacements. The output transistor is rated for 70V collector-emitter and 50mA continuous current, so it can directly drive a small relay coil or a logic-level MOSFET gate through a base resistor. The 300mV maximum Vce(sat) at rated current keeps the on-state voltage drop low enough to avoid thermal issues in the 6-SOIC package at moderate duty cycles.
Temperature grade and storage
Rated for -55°C to 110°C operating, this optocoupler spans the full industrial temperature range with margin into cold environments like outdoor telecom cabinets or engine-bay electronics. The 110°C upper limit is below the 125°C automotive-grade threshold, but still covers most factory-floor and infrastructure gear. Storage temperature exceeds the operating range — the reels should be kept in a dry cabinet if the original moisture-barrier bag has been opened, though the 6-SOIC body is small and typically MSL 3 (168-hour floor life), so standard handling suffices for production runs.
Lifecycle and sourcing posture
The part is ROHS3 compliant, which clears it for EU and most global markets without exemption paperwork.