Do I have to attend the electrostatic loading and ground potential differences ?
Yes. Electrostatic Discharge (ESD) can damage a sensitive electronic component ! 
Under several conditions static electricity and ground potential
differences between the Access Device and the user's target hardware
can build up high voltages - over 10000 Volts (10 kV) in some cases.
The electrostatic discharge of this build-up voltage results in fast
high current waveforms and fast magnetic (H-field) or electrostatic
(E-field) disturbances.
The discharge into the electronic
components and circuitry can damage or destroy hardware components,
resulting in failures and reduced reliability. Because of the
non-hot-pluggable 3.3 Volts / 5 Volts - TTL properties of the JTAG and
the 3Pin/Serial connectors, these ports are endangered especially. The
maximum voltage on these pins may not exceeded 5.5 Volts against the UADs ground, especially in the case that the ground planes are not connected first.
To protect your hardware against damage from static electricity and
ground potential discharge, you should follow some basic precautions: -
Before you change any cable connections from the Access Device, please
remove the power from the Access Device and your target system.
-
Please ensure that the static electricity and ground potentials between
the Access Device, the host PC and the target hardware are balanced. If
there is a danger of high potential differences, you must connect the
Access Device, the host PC and the target hardware to the same ground
domain via a low resistance connection.
- Establish the target connection and power on the systems.
In all cases, the following rule must be attended:
The first connection between the devices must be done via the ground !
Solution
All Universal Access Devices are equipped with a ground socket on the
front side. Please use this ground socket for discharging the static
electricity and balancing ground potentials between the Universal
Access Device, the host PC and the target hardware BEFORE you connect the target hardware to the Access Device.
An additional protection for UAD can be achieved by using the JTAG
Protector. In hard process environments it is strongly recommended to
use the UAD-JTAG-Protector. The UAD2+ contains the protection function
already. Please note, that the JTAG Protector DOES NOT suspend the precautions described above. |
