The OP593A from TT Electronics is a Phototransistor with Collector Emitter Voltage (Breakdown) 30 V, Collector-Dark Current 100 nA, Collector Emitter Voltage(Saturation) 0.40 V, Emitter Collector Voltage(Breakdown) 5 V, On-State Collector Current 3 mA. More details for OP593A can be seen below.