US 2002/0160558 A1 · Method and device for reading and for checking the time position of data response signals read out from a memory module to be tested

Abstract

A method and a device for reading and for checking the time position of a data response read out from a memory module to be tested, in particular a DRAM memory operating in DDR operation. In a test receiver, the data response from the memory module to be tested is latched into a data latch with a data strobe response signal that has been delayed. A symmetrical clock signal is generated as a calibration signal. The calibration signal is used to calibrate the time position of the delayed data strobe response signal with respect to the data response. The delayed data strobe response signal is used for latching the data response. The delay time is programmed into a delay device during the calibration operation and also supplies a measure for testing precise time relationships between the data strobe response signal (DQS) and the data response.

Claims20

Dependent claims

A method for reading and checking a time position of a data response read out from a memory module undergoing test, which comprises:

generating a strobe response signal and a data response in a memory module to be tested;
in a test receiver, generating a strobe signal from the strobe response signal that was generated in the memory module;
and
using the strobe signal to read the data response from the memory module.

1 more element

In combination with a memory module that generates a strobe response signal and a data response while undergoing a test, a test receiver for reading and checking a time position of the data response read out from the memory module, the test receiver comprising:

a test signal input for receiving the data response from the memory module;
at least one latch circuit for storing the data response received from the memory module, said latch circuit connected to said test signal input;
and
a delay device having a programmable delay time and a set input;
said delay device receiving the data strobe response signal from the memory module and operating, in a test cycle, to delay the data strobe response signal by the delay time to obtain a delayed strobe signal;
said delay device supplying the delayed strobe signal to said set input of said latch circuit such that the data response is stored in said latch circuit.

3 more elements

Dependencies are inferred from the claim text.

Method and device for reading and for checking the time position of data response signals read out from a memory module to be tested

Life of this patent

Method and device for reading and for checking the time position of data response signals read out from a memory module to be tested

Life of this patent

Abstract

Claims20