Conformity Magazine - June 2008 - (Page 33)

uman Body Model (HBM) is the oldest of the ESD test methods for testing integrated circuits. It is hard to overestimate the positive impact that this test method has had on the electronics industry. Without the ESD robustness built into electronic components in order to pass this test, there certainly would be enormous expenditures to deal with components damaged by ESD during manufacture. However, the HBM standard was developed in the 1970s and 1980s when integrated circuits had far fewer pins and only one or two power supplies. As integrated circuits have grown in complexity and performance, the basic HBM standard has been applied to the newer circuits. This has only been possible with the introduction of increasingly more sophisticated and complex automated HBM simulators, able to handle in excess of 2000 pins. (In ESD terminology an HBM simulator is a machine that delivers a stress pulse to simulate an ESD event. It is not a computer program.) The combination of sophisticated test equipment and modern integrated circuits with lower operating voltages and multiple power supplies, each with many parallel pins, has resulted in some “unintended consequences.” This article will review the basics of the HBM test method, and some of the issues that have arisen over the years as HBM has been performed on newer and newer technologies. Issues that will be discussed include, long test times, wear out, “trailing pulse,” “pre-pulse voltage,” parasitic effects due to test sample to test system interaction, and acceptable qualification levels. HBM Basics The basic circuit model is shown Figure 1. A 100pF capacitor is discharged through a 1500 Ω resistor and the device under test (DUT). The test system is calibrated by measuring the current through a short and a 500 Ω resistor. The required waveform for a short includes a 2 to 10 ns rise time, a peak current that scales with voltage, a nominal 150 ns decay time and ringing not to exceed 15% of the peak current. The waveform requirements are detailed in the test standards by JEDEC [1] and ESDA [2]. A sample HBM waveform into a short for 2000V is shown in Figure 2. The pin combinations for HBM testing are described in Table 1. A power supply group is any group of pins metallically connected in the integrated circuit package or on the die and providing power to the circuit. Ground pins are considered power supply pins. The intent of the pin combinations in Table 1 is to stress all current paths that could experience ESD stress. Test Time The test time for HBM has risen dramatically in recent years. Part of the problem is increased number of pins, but more significant is the increase in the number of power pin groups. Consider a 500 pin device with 2 40 pin power groups for power and ground. A full stressing of this circuit requires 2680 stresses (1340 positive and 1340 negative). If the design DAMPED OSCILLATORY WAVES – Scalable Solutions to IEC61000-4-18, 60255 series, & ANSI / IEEE C37.90 on Power and I/O lines. Primary unit provides 100 kHz and 1 MHz. Extension adds 3, 10, 30 MHz at any time. Models MIG-OS-OS1 or MIG0603OSI. H HARMONICS & FLICKER - Total solution. Simple to use. Complies with 61000-3-2 Eds. 1, 2, 3 and 61000-3-3. Report with tabular and graphic data including new 200% of limit analysis, average and maximum harmonics as a percentage of limits. Model HAR1000. ESD/EFT/SURGE/DIPS/MAG – Integrated solutions for full compliance configurations to IEC Basic Standards. Available SURGE waveforms include Combination, Ring, 10/700 waves at 4kV and 6kV plus ability to couple all phases & neutral to ground as specified in ANSI/IEEE C62.41. Model TRA2000 series. CE Mark Test Solutions Look to HVT for turn key transient test solutions meeting the latest specifications. User Friendly, Repeatable, Reliable. Damped Oscillatory Wave Harmonics & Flicker ESD/EFT/SURGE/DIPS/MAG IEC 61000-4-18, 60255; ANSI/IEEE C37.90.1 IEC 61000-3-2, -3; IEC61000-4-7, -13, -14, -17, -28 IEC 61000-4-2, -4, -5, -8, -9, -11, -12, -16, -29; ITU-T K.44; ANSI/IEEE C37.90; C62.41 Contact us today to add some real Firepower to your test equipment arsenal. Tel: 703-365-2330 • www.hvtechnologies.com e-mail:emcsales@hvtechnologies.com http://www.hvtechnologies.com/firepower/firepower_ad.html http://www.hvtechnologies.com/firepower/firepower_ad.html

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Conformity - June 2008 Contents Editor's Note 700 MHz Auction Raises a Record $20 Billion FCC Modifies PCS and AWS Power Limit Rules for Broadband Wireless Commission Designates Spectrum Test Bed FCC Releases Report on Wireless Competition Commission Proposes $5 Million Fine for Slamming Using EDX for Non-Destructive Detection of Lead in Consumer Products ESD Open Forum Challenges in Testing - Improving Election Security and Accuracy Part 1 Challenges in Testing - Human Body Model: The Hidden Challenges High-Speed Signal Integrity Considerations for ESD Components Focus On...EMC Components Buyer's Guide FCC Levies $2.6 Million Fine for Junk Faxes FDA Updates Guidance on its Product Review Process EU Issues Updated Energy Star Regulations EU Repeals Directive on Veterinary Electro-Medical Equipment New Product Announcements Updated Standards List for the EU's PPE Directive CPSC Announces New Effort to Keep Out Hazardous Products CPSC Actions in the News IEC Standards Update UL Standards Update Product Reviews Telcordia Standards Update From Our "You Can't Make This Stuff Up" Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity - June 2008

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