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Final test load board checker tool enhancement

IP.com Disclosure Number: IPCOM000246005D
Publication Date: 2016-Apr-26
Document File: 4 page(s) / 82K

Publishing Venue

The IP.com Prior Art Database

Abstract

This disclosure describes an approach for a checker board tool that makes it possible to test a load board, including the test socket, for >95%.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

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Final test load board checker tool enhancement

     This disclosure describes an approach for a checker board tool that makes it possible to test a load board, including the test socket, for >95%.

Background

     
Testing a load board is normally (very) limited. Often, extra hardware must be used to test the load board (LB). However, because of the limited space on the LB (multi-site), the use of extra hardware is not always possible. In most cases it is not possible to test the socket, which is the part of the testing equipment on the load board that interfaces with the device being tested (e.g., connections of the device under test make contact with pins in the test socket).

Abbreviations used herein:


IC: Integrated Circuit
ATE: Automatic Test Equipment
LB: Load Board
QFP: Quad Flat Package
PCB: Printed Circuit Board

     To test an IC, an ATE and a LB is needed. To guarantee both ATE and LB are working correct, they need to be checked and/or calibrated. For the correct working and calibration of the ATE, a procedure is provided by the ATE supplier. Since the LB is designed in house, this procedure needs to be developed in house. This procedure needs to check if the hardware on the LB is working correct (e.g., connections, relays, resistors, capacitors, op amps, etc.). A special program is needed (or checker) to check the LB on the ATE.

     Checking the functionality of a load board is limited. This is caused by the fact that not every component or connection can be reached by an ATE instrument (e.g. channel). Checking the socket is (in most cases) not possible at all.

     An example testing configuration is shown below in Figure 1. It is noted that only relay A and corresponding connections can be tested via channel 1 and 2.

     Example 1: Relay A is closed. By setting Ch.1 @ 0V and Ch. 2 @ 10mA, a current will flow from Ch.2 => Ch.1. The voltage can be measured on Ch.2. Based on this voltage, a

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judgement can be made about whether the relay and connections on the load board are O.K. or not. The remaining relay and connections on the load board, including the socket, can't be tested.

     Example 2: Relay B is closed. By setting Ch.3 @ 10mA, the current will not flow because there is an open end at pin 2. The measured voltage on Ch.3 is the clamp voltage of the source on Ch.3. Based on this voltage, a judgement can't be made.

In practice this means that a big part of the LB can't be tested.

Figure 1

     One way to address this problem is by connecting all pins together in a special device (daisy chain) and putting this device in the socket, making it possible to test more connections, relay B and socket pins. However, some socket pins (Gnd and Supply A pins) are still in parallel and...