Lakeshore 336, User Manual

Page: 173 / 192

8.11 Electrostatic Discharge 161
|
www.lakeshore.com
8.11 Electrostatic
Discharge
Electrostatic Discharge (ESD) may damage electronic parts, assemblies, and equip-
ment. ESD is a transfer of electrostatic charge between bodies at different electro-
static potentials caused by direct contact or induced by an electrostatic field. The
low-energy source that most commonly destroys Electrostatic Discharge sensitive
devices is the human body, which generates and retains static electricity. Simply
walking across a carpet in low humidity may generate up to 35,000 V of
static electricity.
Current technology trends toward greater complexity, increased packaging density,
and thinner dielectrics between active elements, which results in electronic devices
with even more ESD sensitivity. Some electronic parts are more ESD sensitve than
others. ESD levels of only a few hundred volts may damage electronic components
such as semiconductors, thick and thin film resistors, and piezoelectric crystals
during testing, handling, repair, or assembly. Discharge voltages below 4000 V cannot
be seen, felt, or heard.
8.11.1 Identification of
Electrostatic Discharge
Sensitive Components The following are various industry symbols used to label components as
ESD sensitive.
Pin Symbol Description
1 DIO 1 Data input/output line 1
2 DIO 2 Data input/output line 2
3 DIO 3 Data input/output line 3
4 DIO 4 Data input/output line 4
5 EOI End or identify
6 DAV Data valid
7 NRFD Not ready for data
8 NDAC No data accepted
9 IFC Interface clear
10 SRQ Service request
11 ATN Attention
12 SHIELD Cable shield
13 DIO 5 Data input/output line 5
14 DIO 6 Data input/output line 6
15 DIO 7 Data input/output line 7
16 DIO 8 Data input/output line 8
17 REN Remote enable
18 GND 6 Ground wire—twisted pair with DAV
19 GND 7 Ground wire—twisted pair with NRFD
20 GND 8 Ground wire—twisted pair with NDAC
21 GND 9 Ground wire—twisted pair with IFC
22 GND 10 Ground wire—twisted pair with SRQ
23 GND 11 Ground wire—twisted pair with ATN
24 GND Logic ground
TABLE 8-7 IEEE-488 rear panel connector details
FIGURE 8-9 Symbols indicating ESD sensitivity