Abstract: A current sensor for use with a charged device model (CDM) tester includes an outer conductor and a cylindrical inner conductor. The inner conductor is positioned within a central cylindrical bore of the outer conductor to provide a characteristic transmission line impedance of approximately 50 ohms. A test probe conductor extends from the distal end of the inner conductor and is electrically connected to the inner conductor. An array of self-supporting ceramic chip resistors is radially positioned between the distal ends of the inner conductor and the outer conductor to provide a uniformly distributed resistance between the inner conductor and the outer conductor. When the test probe conductor is applied to a pin of a charged device under test (DUT), a discharge current passes through the resistors and produces a voltage on the inner conductor that is provided as a signal voltage proportional to the discharge current.

Abstract: A signal generator produces an output signal in response to an input step signal using two transmission lines with characteristic impedances corresponding to the impedances of a signal source and a load. The input signal is applied to the inner conductor of the first transmission line, which has the outer shield grounded. The input signal is applied to the outer shield of the second transmission line, which has a floating outer shield. The inner conductor and the outer shield of the first transmission line are open at the second end. The inner conductor and the outer shield of the second transmission line are shorted at the second end. This transmission line is bridged by two resistors, the junction of which is connected to the inner conductor of the transmission line. The output signal has a first step at half the input voltage and a second step at the input voltage.

Abstract: A tester for applying very fast transmission line pulses (“VFTLP”) to select pins of a device under test (“DUT”), for example, an integrated circuit. The tester also provides for leakage measurement testing of the DUT after VFTLP testing. An end of a coaxial cable is received within an aperture formed in a metal ground plane. The outer conductor of the coaxial cable is attached to the metal ground plane and the inner conductor of the coaxial cable projects above an upper surface of the metal ground plane. A grip attached to the metal ground plane selectively retains the DUT upon the upper surface of the metal ground plane in a position placing a select pin in physical contact with the projecting inner conductor of the coaxial cable, completing the VFTLP circuit.

Abstract: A sensor measures the current in high frequency pulses (e.g., pulses having fast rise times) that are transported on coaxial transmission lines. The sensor includes an entrance coaxial conductor and an exit coaxial conductor that are interconnected by a continuous inner conductor. The outer conductors of the two coaxial conductors are interrupted and are interconnected by a sensing resistor with a substantially constant resistance. An output sensor coaxial conductor has an inner conductor electrically connected to a first end of the sensing resistor and has an outer conductor connected to a second end of the sensing resistor. Tapered ferrite cores are placed around the three coaxial conductors proximate the connections to the sensing resistor. Preferably, the sensing resistor is a tubular resistor formed on a dielectric cylindrical tube. The sensor is enclosed within a continuous conductive housing.

Abstract: A pulse generator generates a pulse that is transmitted to a device under test through a signal path that has a substantially constant impedance along its entire length. A voltage on the signal path and a current therethrough is measured in response to the pulse being generated.