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 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
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.