Electrostatic discharge (ESD) is a sudden and momentary flow of electric current between two differently-charged objects when brought close together or when the dielectric between them breaks down, often creating a visible spark associated with the static electricity between the objects.
(Quote from Wikipedia)
The real world in which ICs are used is full of hazards to them. One of the main characteristics of any system is its reliability under conditions of significant stresses. And immunity of IC-based systems to high-voltage electrostatic discharges is one of the most important requirements.
There are many ways to test chips for ESD resistance. Typically, this process requires the use of some measuring instruments. One possible combination of measuring equipment to perform such a test is described below.
One of typical scenario we have done in Computer Controls Srl. We have tested the volt-ampere characteristics of each individual IC’s pin before and after the ESD stress test. For this purpose, a special PCB was used on which each pin is separately derived for testing. A high-side driver IC, which has power supply pins, digital and analog inputs and outputs, was selected as the object for testing. Thus, we can say that this is one of the typical cases.
To perform the volt-ampere performance testing, the following were selected:
- A compact precision single-channel source/measure unit (SMU) B2901A from Keysight → Successor: B2901B
- DAQ970A Data Acquisition System from Keysight
- DAQM900A 20 Channel Solid-state Multiplexer Module for DAQ970A to avoid manual rewiring of IC pins and ensure guaranteed identical measurement conditions
- Keysight BenchVue DAQ software to manage the test routine
The B2901A from Keysight is a single-channel source/measure unit (SMU) with minimum source resolution at 1 pA /1 μV, minimum measurement resolution at 100 fA / 100 nV and maximum output at 210 V, 3 A DC. Also, it has built-in arbitrary waveform generator and digitizing capabilities from 20 μs interval.
DAQ970A Data Acquisition System from Keysight has 6½-digit (22-bit) internal DMM, scanning up to 450 channels per second with solid-state multiplexer module (in our case we have used 20-channel DAQM900A Solid-state Multiplexer Module). It can measure thermocouples, RTDs and thermistors, AC/DC volts and current; resistance, frequency/period, make diode test and measure capacitance through built-in signal conditioner. Measured data holds in non-volatile memory when power is removed.
The DAQM900A Solid-state Multiplexer Module that we used for tests, has 20 channels and can scan up to 450 channels per second in two- and four-wire scanning modes. It can measure up to 120 V signals and uses built-in thermocouple reference junction.
Before conducting the ESD stress test, the volt-ampere characteristics of all pins of the IC were measured. With the use of such a set of tools and a laptop with the installed BenchVue software it did not cause any difficulties.
Exactly the same measurements were made after the application of the ESD stress test action was completed. By comparing these measurements before and after the test, it was possible to understand how immune the tested IC was to ESD.
The applied voltages ranged from zero to the maximum possible voltages according to the manufacturer's specification described in the IC datasheet. The values of input and output currents were compared with the values described in the datasheet. You can see examples of some measured volt-ampere characteristics in the pictures.
As a result, we concluded that this IC fully complies with the ESD immunity parameters described in the documentation.
Of course, the described set of testing tools is not the only possible one. But thanks to the combination of a precision voltage source, voltage and current meter and data acquisition system, combined with Keysight's user-friendly BenchVue DAQ software, this test was performed quickly, easily and very accurately.
Computer Controls, as an authorized Keysight partner, is able to equip any test or research laboratory with all the necessary measurement equipment to ensure the most accurate and comfortable measurements possible.
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