To be useful on a production line,a dynamic test For production testing,the advantages of computer system must be compatible with automatic handling control are overwhelming.There is,in fact,no real al- equipment and probers,and here the normal problems of ternative;the number of parameters that may have to be preserving clean test waveforms are multiplied a thou- measured at one time or another is well beyond the reach sandfold because the pulses involved are extremely fast. of a hardware-only system.Even with computer-op- Another practical requirement is that dynamic tests be erated systems,the variations in test requirements are so performed along with functional and dc tests,in a single great that much of the test programming must take the insertion of the IC in the test socket. form of"performance boards,"which are special-pur- Despite many technological obstacles,dynamic testing pose plug-ins incorporating the output loads and circuits has now come of age.At least one computer maker needed to test a given family of devices. has turned to 100 percent dynamic testing of all ICs in An interesting sidelight is that linear ICs are much more incoming inspestion,in an effort to find dynamically thoroughly tested than their nonmonolithic predecessors. defective devices before they can be loaded on circuit Consider,for example,the list of tests performed by an boards.The price of discovering defective devices after automatic test system on a stereo demodulator in IC they already have been assembled in circuits is simply too form: great. 1.Power consumption. 2.Left and right output level The testing of semiconductor memories 3.Audio mute on and off thresholds. Semiconductor memories are functionally and para- 4.Audio mute attenuation. metrically tested like other ICs,but the fact that they have 5.Audio mute thump. fixed outputs somewhat simplifies the problem.Various 6.Channel balance. test patterns are used to ensure that the reading or the 7.Rejection tests for 19-and 38-kHz components writing of a bit of memory will not affect the logic in 8.Stereo separation. adjacent cells.One commonly used pattern is a checker- 9.Monaural distortion. board of 1's and 0's.Another is the floating of a 1 or a 0 10.Stereo distortion. from cell to cell while the adjacent cells are maintained 11.Lamp on and off threshold. in the opposite state.There are many variations on these 12.Stereo muting on and off threshold. themes. This entire complement of tests,plus an automatic Where only a limited number of memory types are to pilot-subcarrier phase adjustment,can be made in well be tested one may turn to a special-purpose memory under a second by a computer-operated test system. exerciser such as that shown in Fig.5.In this instrument, It is doubtful that any discrete-component stereo de- the Macrodata MD-100,the desired patterns are stored modulator was ever as thoroughly tested in production, on read-only memories and the device signal and timing a good deal of manual trimming and tweeking notwith- information is programmed on plug-in "personality standing. cards.” Although the more advanced consumer circuits must be The larger,computer-operated IC test system,on the tested by large computer-operated systems,simpler de- other hand,brings the many advantages of computer vices such as operational amplifiers,voltage regulators, control to memory testing.Most important of these is and comparators can be tested in incoming inspection by the ability to handle any semiconductor memory without small bench-type instruments,typically programmed by the need for additional equipment. plug-in circuit boards.One such instrument,the General The generation of test patterns for memories is simple Radio Type 1730 Linear Circuit Tester,is shown in Fig. in concept,but with even moderate-size memories the pattern length is long enough to be a consideration. Floating I's and 0's through a 256-bit memory requires more than 120 000 functional tests,which are too many for economical storage in core or for fast disk-to-core FIGURE 5.A noncomputer-operated tester for semi- transfer.One answer to this problem is on-line pattern conductor memories (the Macrodata MD-100). generation,which allows a test system to produce patterns as it tests,using only about 1200 words of minicomputer memory. The testing of linear ICs ◆0000000000900QQ000Q0000Q●￥ Until a year or so ago,"linear IC testing"meant,for all practical purposes,the testing of operational ampli- fiers,which in turn meant the measurement of the offset voltage,offset current,open-loop gain,power capability, ◆Q00000QQ666666656 common-mode rejection,and a few other dc character- istics of these devices.More recently,however,several other types of linear IC have begun to appear in volume, 00000009 many of them for consumer-electronics applications. Now linear IC testing includes the testing of circuits as diverse as voltage regulators and television chroma demodulators.Thus there is little that can be said of linear testing in general,beyond some observations on the types of test equipment commonly used. Van Veen-An introduction to IC testingTo be useful on a production line, a dynamic test For production testing, the advantages of computer system must be compatible with automatic handling control are overwhelming. There is, in fact, no real al￾equipment and probers, and here the normal problems of ternative; the number of parameters that may have to be preserving clean test waveforms are multiplied a thou- measured at one time or another is well beyond the reach sandfold because the pulses involved are extremely fast. of a hardware-only system. Even with computer-op￾Another practical requirement is that dynamic tests be erated systems, the variations in test requirements are so performed along with functional and dc tests, in a single great that much of the test programming must take the insertion of the IC in the test socket. form of "performance boards," which are special-pur￾Despite many technological obstacles, dynamic testing pose plug-ins incorporating the output loads and circuits has now come of age. At least one computer maker needed to test a given family of devices. has turned to 100 percent dynamic testing of all ICs in An interesting sidelight is that linear ICs are much more incoming inspeGtiOn, in an effort to find dynamically thoroughly tested than their nonmonolithic predecessors. defective devices before they can be loaded on circuit Consider, for example, the list of tests performed by an boards. The price of discovering defective devices after automatic test system on a stereo demodulator in IC they already have been assembled in circuits is simply too form: great. 1. Power consumption. 2. Left and right output level. The testing of semiconductor memories 3. Audio mute on and off thresholds. Semiconductor memories are functionally and para- 4. Audio mute attenuation. metrically tested like other ICs, but the fact that they have 5. Audio mute thump. fixed outputs somewhat simplifies the problem. Various 6. Channel balance. test patterns are used to ensure that the reading or the 7. Rejection tests for 19- and 38-kHz components. writing of a bit of memory will not affect the logic in 8. Stereo separation. adjacent cells. One commonly used pattern is a checker- 9. Monaural distortion. board of l's and 0's. Another is the floating of a I or a 0 10. Stereo distortion. from cell to cell while the adjacent cells are maintained 11. Lamp on and off threshold. in the opposite state. There are many variations on these 12. Stereo muting on and off threshold. themes. This entire complement of tests, plus an automatic Where only a limited number of memory types are to pilot-subcarrier phase adjustment, can be made in well be tested one may turn to a special-purpose memory under a second by a computer-operated test system. exerciser such as that shown in Fig. 5. In this instrument, It is doubtful that any discrete-component stereo de￾the Macrodata MD-100, the desired patterns are stored modulator was ever as thoroughly tested in production, on read-only memories and the device signal and timing a good deal of manual trimming and tweeking notwith￾information is programmed on plug-in "personality standing. cards." Although the more advanced consumer circuits must be The larger, computer-operated IC test system, on the tested by large computer-operated systems, simpler de￾other hand, brings the many advantages of computer vices such as operational amplifiers, voltage regulators, control to memory testing. Most important of these is and comparators can be tested in incoming inspection by the ability to handle any semiconductor memory without small bench-type instruments, typically programmed by the need for additional equipment. plug-in circuit boards. One such instrument, the General The generation of test patterns for memories is simple Radio Type 1730 Linear Circuit Tester, is shown in Fig. in concept, but with even moderate-size memories the pattern length is long enough to be a consideration. Floating l's and 0's through a 256-bit memory requires more than 120 000 functional tests, which are too many for economical storage in core or for fast disk-to-core FIGURE 5. A noncomputer-operated tester for semi￾transfer. One answer to this problem is on-line pattern conductor memories (the Macrodata MD-100). generation, which allows a test system to produce patterns as it tests, using only about 1200 words of minicomputer memory. The testing of linear ICs Until a year or so ago, "linear IC testing" meant, for all practical purposes, the testing of operational ampli￾fiers, which in turn meant the measurement of the offset voltage, offset current, open-loop gain, power capability, common-mode rejection, and a few other dc character￾istics of these devices. More recently, however, several other types of linear IC have begun to appear in volume, many of them for consumer-electronics applications. Now linear IC testing includes the testing of circuits as diverse as voltage regulators and television chroma __l_i___l_i_*_l_l_*___*____ demodulators. Thus there is little that can be said of linear testing in general, beyond some observations on the types of test equipment commonly used. Van Veen-An introduction to IC testing 33