Abstract: A timing signal generator including a direct digital frequency synthesizer (DDFS), a divide-by-N counter, and a pattern generator, produces a TIMING signal conveying a timed sequence of pulses. The pattern generator produces a sequence of data pairs (FREQ,N), with each pair being produced in response to each pulse of the TIMING signal and indicating a time interval that is to occur between that TIMING signal pulse and a next TIMING signal pulse. The DDFS produces an output sine wave signal (SINE) having a frequency controlled by the current FREQ data output of the pattern generator. The divide-by-N counter produces the timing signal pulses. It counts cycles of the SINE signal occurring since it last produce a TIMING signal pulse and generates a next TIMING signal when it has counted the number of SINE signal pulses indicated by the current N data output of the pattern generator.

Abstract: A low-profile, short signal path relay assembly implementing several relays for use in an integrated circuit tester, a digitizer or other equipment requiring multiple relays, includes a chassis and a signal board mounted within the chassis. Each relay includes a control rod slideably mounted within the chassis above the signal board, a resilient contact arm mounted on the signal board below the control arm, and a coil assembly mounted adjacent to a magnetic end of the control rod. A spring is positioned between the control rod and the chassis so that it normally forces the control rod to slide in a direction away from the coil assembly. However when a current is applied to the coil assembly it produces a magnetic flux attracting the magnetic end of the control rod toward the coil assembly.

Abstract: An integrated circuit (IC) tester includes a set of dual-purpose digital/analog channels. Each tester channel includes a driver capable of supplying either a digital or analog test signal input to an IC terminal and a receiver for digitizing and processing either an analog or digital IC output signal appearing at the DUT terminal to produce results data representing the behavior of that IC output signal during a test. A test is organized into a succession of test cycles, and before each test cycle a pattern generator within each channel produces data for controlling the behavior of the driver and receiver during the test cycle. The control data controls whether the driver is to produce an analog or a digital test signal, controls a magnitude or logic level to which the test signal is to be driven during the test cycle, and controls a time during the test cycle of any test signal state or magnitude changes.

Abstract: An integrated circuit (IC) tester includes a set of digital and analog channels, each of which may be programmed to carry out a sequence of test activities at pins of an IC under test. The channels are interconnected by a trigger bus, and each channel may be programmed to respond to a detected event during a test by transmitting a particular trigger code to every other channel via the trigger bus. Each channel may be also programmed to respond to a particular trigger code arriving on the trigger bus by branching its sequence of test activities. Thus any channel detecting an event during a test can signal all other channels to immediately terminate a current sequence of test activities and branch to another set of test activities. Such a conditional branch capability enables the tester to automatically perform an "if/then" diagnostic test on an IC in which a test result detected at any point during the test determines the future course of the test.

Abstract: A triggered clock signal generator produces a periodic output clock signal (CLOCK3) in response to an input TRIGGER signal, wherein a delay between the TRIGGER signal and the first pulse of the CLOCK3 signal is accurately adjustable. The apparatus includes a period generator and a phase adjuster. The period generator, using a periodic input signal (CLOCK1) as a timing reference, responds to the TRIGGER signal by producing a periodic output clock signal (CLOCK2) in adjustably delayed response to a next pulse of the CLOCK1 signal. The phase adjuster phase shifts the CLOCK2 signal to produce the CLOCK3 signal. The phase adjuster compares the phase of the CLOCK1 signal to the phase of the TRIGGER signal to determine an appropriate amount by which to phase shift the CLOCK2 signal so that the time delay between the TRIGGER signal and the first pulse of the CLOCK3 signal is independent of the phase relation between the TRIGGER and CLOCK1 signals.

Abstract: A general purpose integrated circuit (IC) tester includes a set of channels, one for each input or output pin of an IC device under test (DUT). Each channel is programmed by a host computer to either supply a test signal to a DUT I/O pin or sample a DUT output signal appearing at the I/O pin and produce sample data representing its magnitude or logic state. The tester also includes an amorphous logic circuit (ALC) having a set of input and output terminals and a programmable logic circuit interconnecting the input and output terminals. Some of the ALC input and output terminals receive the sample data produced by each channel and other ALC terminals send control signals directly to each channel. Other ALC terminals transmit data to the host computer.

Abstract: A drive circuit for an integrated circuit tester operates in either a drive mode of a termination mode. In the drive mode, the drive circuit supplies a differential test signal to an integrated circuit device under test (DUT) via a pair of transmission lines. In its termination mode, the drive circuit terminates the transmission lines with their characteristic impedances and provides an adjustable load to a DUT output signal appearing on the transmission lines.

Abstract: A digitizer can be programmed to digitize an ANALOG signal with a complex frequency pattern determined in response to set of trigger signals. The digitizer includes an addressable packet memory storing a set of data packets and produces one of its stored data packets as output when addressed. The output data packet includes both PERIOD and MODE data fields. The digitizer also incudes an analog-to-digital converter for digitizing the ANALOG signal at the frequency controlled by the PERIOD data output of the packet memory. The MODE data output of the packet memory tells a trigger logic circuit how to choose a next packet memory address and selects one of the trigger signals to tell the trigger logic circuit when to change the packet memory address so as to alter the digitizing frequency.

Abstract: A differential driver includes an input stage and an output stage. The input stage receives a differential INPUT signal to produce a differential DRIVE signal of state determined by the INPUT signal. The output stage receives the DRIVE signal and produces a differential OUTPUT signal of state determined by the DRIVE signal. The OUTPUT signal voltage can be adjusted within any of multiple ranges. The output stage adjusts its output load resistance for each OUTPUT signal voltage range in order to maximize operating speed while limiting power consumption in each range. The input stage automatically reduces the voltage of the DRIVE signal input to the output stage for low OUTPUT signal voltages to reduce noise in the OUTPUT signal.

Abstract: A drive circuit for an integrated circuit tester operates in either a drive mode of a termination mode. In the drive mode, the drive circuit supplies a differential test signal to an integrated circuit device under test (DUT) via a pair of transmission lines. In its termination mode, the drive circuit terminates the transmission lines with their characteristic impedances and provides an adjustable load to a DUT output signal appearing on the transmission lines.

Abstract: Apparatus for testing an integrated circuit device (DUT) having an input port and an output port comprises multiple state devices each having multiple states that occur in a predetermined sequence and each having an output port at which it provides an event signal representative of its current state. At least a first of the state devices is an emitting device that emits an event marker signal at a predetermined time in advance of entering a predefined state, at least a second of the state devices is a receiving device that responds to receipt of an event marker signal in a predetermined manner after lapse of a predetermined time, at least one of the state devices has its output port connected to the input port of the DUT, and at least one of the state devices is a measurement device connected to the output port of the DUT. An interconnection matrix is connected to each state device and allows each state device to communicate an event marker signal to each other state device.

Abstract: An arbitrary waveform generator using packet data words to represent segments of a desired complex waveform includes a variable clock. Each packet data word contains a clock control word that is used to control the variable clock frequency so that the duration of each segment is adjusted to produce the desired complex waveform.