Browse Prior Art Database

Method for Testing AC Parameters of Logic Networks

IP.com Disclosure Number: IPCOM000101093D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Fujita, N: AUTHOR

Abstract

A test method for logic circuit networks comprising flip-flop circuits and combination logic circuits is disclosed. The method uses two clocks to test AC parameters of the networks.

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Method for Testing AC Parameters of Logic Networks

       A test method for logic circuit networks comprising
flip-flop circuits and combination logic circuits is disclosed.  The
method uses two clocks to test AC parameters of the networks.

      Fig. 1 shows an example of a logic circuit network to be tested
by the present test method, which comprises flip-flop circuits 10,
14, 18 and combination logic circuits 12, 16.  The flip-flop circuits
are di- vided into two groups: a first group consisting of alternate
flip-flops driven by clock-A and a second group consisting of the
remaining ones driven by clock-B.  The illustrated network includes
only one flip-flop 14 in the second group. The conditions required
for correct operations of the network are given by the following.
      T1 - Tab >  Setup Time of Flip-Flop 14       (1)
      T2 - Tcd >  Setup Time of Flip-Flop 18       (2)
where T1:  time from leading edge of clock-A to leading edge of
clock-B
       T2:  time from leading edge of clock-B to leading edge of
clock-A
       Tab:  propagation delay of (flip-flop 10 + circuit 12)
       Tcd:  propagation delay of (flip-flop 14 + circuit 16)
By adjusting the clock-B to vary T1 and T2, it is possible to measure
Tab and Tcd.  In a first step to measure Tab, T1 is set to a
minimum time which meets the condition (1) above.  In a second step
to measure Tcd, T2 is set to a minimum time which meets the condition
(2). ...