Electrostatic discharge (ESD) protection is provided for discharging current between input and output nodes. In accordance with various embodiments, an ESD protection device includes an open-base transistor having an emitter connected to the input node and a collector connected to pass current to the output node via a resistor in response to a voltage at the input node exceeding a threshold that causes the transistor to break down. The resistor is coupled across emitter and collector regions of a second open-base transistor that is configured to turn on for passing current in response to the current across the resistor exceeding a threshold that applies a threshold breakdown voltage across the second transistor. In some implementations, an emitter and/or base of the second transistor are connected to, or are respectively the same region as, a base and a collector of the first transistor.