Browse Prior Art Database

ANALOG HARDWARE BUILT-IN SELF TEST ARCHITECTURE

IP.com Disclosure Number: IPCOM000007543D
Original Publication Date: 1995-Nov-01
Included in the Prior Art Database: 2002-Apr-04
Document File: 3 page(s) / 144K

Publishing Venue

Motorola

Related People

Mark Spiotta: AUTHOR

Abstract

Increasing product complexities and shrinking product sizes drives higher functional and device inte- gration levels. Increased integration has many advan- tages, but also has the disadvantage of reduced testability due to reduced observability and control- lability of internal nodes. In addition, customers expect the products to be more and more capable of detecting and diagnosing problems by itself, Existing fault detection and diagnosic methods are currently limited to "off-line" testing, where a known stimulus is applied to the circuit-under-test, and the circuit response is monitored and compared to the expected values. Furthermore, a thorough test of the hardware-particularly analog hardware-is usually only possible in a dedicated test fixture, such as the manufacturing front-end board-level test area. DESCRIPTION OF THE INVENTION: The invention provides a two-phased method of assessing the analog hardware "health" using non- traditional built-in selftest (BIST) techniques.

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Page 1 of 3

MmROLA Technical Developments

ANALOG HARDWARE BUILT-IN SELF TEST ARCHITECTURE

by Mark Spiotta

PROBLEM SOLVED BY THE INVENTION:

  Increasing product complexities and shrinking product sizes drives higher functional and device inte- gration levels. Increased integration has many advan- tages, but also has the disadvantage of reduced testability due to reduced observability and control- lability of internal nodes. In addition, customers expect the products to be more and more capable of detecting and diagnosing problems by itself,

  Existing fault detection and diagnosic methods are currently limited to "off-line" testing, where a known stimulus is applied to the circuit-under-test,

and the circuit response is monitored and compared to the expected values. Furthermore, a thorough test of the hardware-particularly analog hardware-is usually only possible in a dedicated test fixture, such as the manufacturing front-end board-level test area. DESCRIPTION OF THE INVENTION:

  The invention provides a two-phased method of assessing the analog hardware "health" using non- traditional built-in selftest (BIST) techniques.

The first phase testing occurs during normal oper- ation and thus does not!interfere with the expected

BLOCK INPUTS

BLOCK INPUTS

FUNCTIONAL BLOCK No. 1 (DUT 1)

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BLOCK OUTPUTS

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NOTE: THE MUX A"- . I_ .--

      NU A/U AKt *,\LL, , n,lT OF THE UNCTIONAL CIRCUITRY ,Nn THIIS MAY NOT

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Fig. 1 Non-Intrusive Analog Circuit Test Architecture

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MolylRoLA Technical Developments

operation of the hardware. Hardware faults are detected by using dedicated test circuitry to moni- tor the outputs of various analog processing blocks and then comparing the results with the expected performance. For instance, a discrete fourier trans- form could be periodically taken on the output of a transmit splatter filter; if excessive spectral compo- nents exist beyond the bandwidth of the filter, then a potential fault is detected. Figure 1 illustrates such a non-intrusive analog circuit test architecture.

  The MUX & A/D are typically part of the func- tional circuitry, so the A/D output can be unobtrus- ively monitored by the BIST circuitry. The Signal Analysis Block can be as simple as a level detector
(i.e. detect deviation levels in excess of specified lim- its) to as complex as a Discrete Fourier Transform processing block which detects excessive out-of-band energy which should have been filtered out by the Functional Block(s).

  The BIST controller can monitor several Block output signals by periodically sampling them in a round-robin fashion. Any abnormal circuit opera- tion detected by this first phase can prompt the prod- uct controller to enter the second phase ofself-tests.

  Phase two testing consists of "off-line" tests w...