Patent ID: 7977958

Claim:
A probe card apparatus comprising: a plurality of electrical connections to a tester for testing an electronic device; a plurality of probes disposed to contact the electronic device; a plurality of communications channels connecting ones of the electrical connections to ones of the probes; and in a first one of the communication channels, a first amplifier for amplifying a signal output by the electronic device and received at a first one of the probes, the first amplifier providing the amplified signal to a first one of the electrical connections, and a first by-pass resistor providing a resistive electrical path to the first of the probes by-passing the first amplifier for test signals output by the tester and received at the first one of the electrical connections, wherein: the first amplifier is biased such that the first amplifier is off in response to a signal driven through the first one of the electrical connections to the first one of the probes, and the first amplifier is biased such that the first amplifier is on in response to a signal driven through the first one of the probes to the first one of the electrical connections.