EPS-100 Manual Integral Solutions Int’l
August 22, 2013
Page 3
1. Hardware Description
ESD Hardware Option is designed as an add-on to ISI QST-200x testers to study sensitivity of magneto-
resistive heads to electro static discharge. ESD stress can only be done at HGA level and can be run in either
standalone mode or as part of QST test.
ESD option consists of EPS-100 and waveform module. EPS-100 is a power supply, capable of producing +/-
100V with 0.003V resolution. It is universal for all waveform modules. Due to calibration for more precise HBM
and MM amplitude, the waveform module may require voltages slightly higher than 100, which is not supported by
EPS-100. Therefore the maximum HBM and MM firing voltage is +/-90V.
Waveform module is responsible for producing a pulse of a known shape (using one of the standard ESD
models) and switching the head from stressing to testing. There are three standard types of waveform modules:
Charge Device Model (CDM), Human Body Model (HBM), and Machine Model (MM). Newer waveform modules
are located directly on the 2xHGA cartridge in close proximity to the head, and are called cartridge-style. Such
modules can be run standalone or mounted on 2x tooling directly for testing.
Older type module is an add-on to QST that has two 6-pin cables running to standard QST 2xHGA cartridge,
and is called a box-style module. HBM and MM box-style waveform modules do not support any AC measurements.
These modules are no longer manufactured, however EPS-100 supports them as well. A special adapter board for
EPS-100 is required to run the box-style waveform modules.
HBM and MM modules are universal for any flex design; custom mechanics that are required for different
heads are located on the cartridge. So HBM and MM waveform modules can be freely interchanged on one
cartridge. CDM waveform module on the other hand requires unique mechanical configuration for each flex design,
and cannot be mounted on HBM/MM cartridge.
EPS option was designed to work with the automated ESD Sweep test. The test uses EPS to generate controlled
ESD transients and measures head parameters between the pulses to find ESD failure threshold (voltage). Any QST-
200x test, including AC measurements, can be used to characterize the head and find the ESD failure threshold. QST
test requires a QST-200x and either 2xHGA tooling (for cartridge style waveform modules) or 8xHGA tooling for
box-style. To enable this test, add ESDApp.Application to Quasi97
Selected Modules and enable it.
!Important!
It is not recommended to expose any waveform module to magnetic fields higher than 250Oe. When running
QST tests with waveform module close to the magnet, make sure that magnetic field from the QST magnet does not
cause field near waveform modules to exceed 200Oe.
On standard 2-pole HSA/HGA magnet the module is physically inside the magnet so 250Oe limit applies.
However, other magnet design (for example 4-pole or 15K high field) can go to higher fields without affecting the
waveform module due to smaller field leakage in the perimeter. For example QST-2002HF Tester and QST-2002
with Quad-Pole HGA Magnet can go to higher fields.
!Important!
The diodes on Gen2 2xHGA cartridges must be removed in order to work properly with Machine Model (MM)
and Human Body Model (HBM) ESD modules. So the “MR Clamping During Write” feature is not supported by the
HBM/MM Gen2 type cartridges. User must remember the fact that the QST-2002 tester cannot recognize if the
diodes are present or not, so “MR Clamping During Write” even though available in software, will not work. The
diode protection still exists on the 2xHGA GEN2 interface board, using programmable clamping voltage, but it is
enabled in both write and read modes.
!Important!
On Gen2 2xHGA type cartridges, for HBM and MM, the DC cable makes a slight impact on the waveform with
higher resistance read heads. While it is recommended to have it for higher accuracy measurement, it has negative
impact on the amplitude of the HBM waveform (HBM peak on 500ohm reader is ~5% higher with the DC ribbon
cable because of additional capacitance). In order to avoid this phenomena, the DC ribbon cable between the
cartridge and HGA connector board can be removed. In this case the cartridge needs to be reworked as follows:
1) On HGA connector board - remove the R5 and R7.
2) On the G2 2x Universal Cartridge board, install 0ohm resistors on R5-R10.
