A semiconductor device may include a voltage generator configured to generate a first base-emitter voltage of a first bipolar junction transistor, and a failure detector configured to generate a failure signal by comparing the first base-emitter voltage with an upper limit reference voltage and a lower limit reference voltage. The failure detector may include a second bipolar junction transistor a current source configured to generate a bias current, a first resistor coupled between the current source and a emitter of the second bipolar junction transistor to generate the upper limit reference voltage, a second resistor and a third resistor configured to divide a second base-emitter voltage of the second bipolar junction transistor to generate the lower limit reference voltage, and a first and second comparator configured to compare the first base-emitter voltage with the upper limit reference voltage and the lower limit reference voltage, respectively, to generate respective failure signals.