US 5,315,242 AGranted

Method for measuring AC specifications of microprocessor

AssigneeNEC Corporation

InventorTomokazu Enami

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Abstract

In measuring the ac specifications of a microprocessor having within one chip, a clock generator which generates a clock signal, a first connecting terminal for connecting a crystal oscillator which regulates the oscillation frequency of the clock generator, a first driver which amplifies the power of the clock signal, a second connecting terminal which receives an output of the first driver, a peripheral circuit which receives the supply of a clock signal, a CPU which is operated by the clock signal and controls the operation of the peripheral circuit, a second driver which amplifies the power of an output of the CPU, and a third connecting terminal which receives the supply of an output of the second driver, there are executed a first step of measuring the ac specification of the clock generator with the output to the second connecting terminal by applying test pulses from an IC tester to the first connecting terminal under the condition in which the crystal oscillator is removed, and a second step of measuring the ac specification of the CPU with the output to the third connecting terminal by removing a connecting line and applying test pulses from the IC tester to a fourth connecting terminal.

Claims2

Dependent claims

A method for measuring ac characteristics of a microprocessor which has, on a single semiconductor chip, a first terminal, a clock generator coupled to said first terminal, a second terminal, a first driver connected between said clock generator and said second terminal, a peripheral circuit coupled to said clock generator, a CPU, a third terminal coupled to said CPU, a fourth terminal, and a second driver connected between said CPU and said fourth terminal, said clock generator cooperating with a crystal oscillator, which is provided outside said semiconductor chip and connected to said first terminal, to generate a clock signal, said clock signal being supplied to said peripheral circuit and further to said CPU through said first driver, said second terminal, and an interconnection wiring which is provided outside said semiconductor chip between said second and third terminals, said CPU responding to said clock signal to control said peripheral circuit and to output a processed signal to said fourth terminal through said second driver, said method comprising the steps of:

applying a train of first test pulses to said first terminal in place of connecting said crystal oscillator to said first terminal to thereby cause said clock generator to output a train of pulses in response to said first test pulses at said second terminal;
measuring said train of pulses appearing at said second terminal to obtain ac characteristics of said clock generator;
applying a train of second test pulses to said third terminal in place of providing said interconnection wiring between said second and third terminals to thereby cause said CPU to output a processed signal to said fourth terminal in response to said second test pulses;
and
measuring the processed signal appearing at said fourth terminal to obtain ac characteristics of said CPU.

2 more elements

Dependencies are inferred from the claim text.