2–6
DLR/DLO/DLG3416
Design Considerations
For details on design and applications of the DLX3416 using
standard bus configurations in multiple display systems, or par-
allel I/O devices, such as the 8255 with an 8080 or memory
mapped addressing on processors such as the 8080, Z80,
6502, or 6800, refer to Appnote 15 in the curr ent Siemens Opto-
electronics Data Book.
Electrical and Mechanical Considerations
V oltage Transient Suppression
We recommend that the same power supply be used for the
display and the components that interface with the display to
avoid logic inputs higher than V
CC
. Additionally, the LEDs may
cause transients in the power supply line while they change dis-
play states. The common practice is to place .01 mF capacitors
close to the displays across V
CC
and GND, one for each dis-
play, and one 10 mF capacitor for every second display.
ESD Protection
The silicon gate CMOS IC of the DLX3416 is quite resistant to
ESD damage and capable of withstanding discharges greater
than 2 KV. However, take all the standard precautions, normal
for CMOS components. These include properly grounding per-
sonnel, tools, tables, and transport carriers that come in contact
with unshielded parts. If these conditions are not, or cannot be
met, keep the leads of the device shorted together or the parts
in anti-static packaging.
Soldering Considerations
The DLX3416 can be hand soldered with SN63 solder using a
grounded iron set to 260
°
C.
W ave soldering is also possible following these conditions: Pr e-
heat that does not exceed 93
°
C on the solder side of the PC
board or a package surface temperature of 85
°
C. W ater soluble
organic acid flux (except carboxylic acid) or resin-based RMA
flux without alcohol can be used.
W ave temperature of 245
°
C
±
5°C with a dwell between 1.5 sec.
to 3.0 sec. Exposure to the wave should not exceed tempera-
tures above 260°C for five seconds at 0.063" below the seating
plane. The packages should not be immersed in the wave.
Post Solder Cleaning Procedures
The least offensive cleaning solution is hot D.I. water (60°C) for
less than 15 minutes. Addition of mild saponifiers is acceptable.
Do not use commercial dishwasher detergents.
For faster cleaning, solvents may be used. Carefully select any
solvent as some may chemically attack the nylon package.
Maximum exposure should not exceed two minutes at elevated
temperatures. Acceptable solvents are TF (trichorotribluore-
thane), TA, 111 Trichloroethane, and unheated acetone.
Note: Acceptable commercial solvents are: Basic TF, Arklone,
P. Genesolv, D. Genesolv DA, Blaco-Tron TF, Blaco-Tron TA, and
Freon TA.
Unacceptable solvents contain alcohol, methanol, methylene
chloride, ethanol, TP35, TCM, TMC, TMS+, TE, or TES. Since
many commercial mixtures exist, contact a solvent vendor for
chemical composition information. Some major solvent manu-
facturers ar e: Allied Chemical Corportation, Specialty Chemical
Division, Morristown, NJ; Baron-Blakeslee, Chicago, IL; Dow
Chemical, Midland, MI; E.I. DuPont de Nemours & Co., Wilm-
ington, DE.
For further information refer to Siemens Appnotes 18 and 19.
An alternative to soldering and cleaning the display modules is
to use sockets. Standard pin DIP sockets .600" wide with
0.100" centers work well for single displays. Multiple display
assemblies are best handled by longer SIP sockets or DIP
sockets when available for uniform package alignment. Socket
manufacturers are Aries Electronics, Inc., Frenchtown, NJ;
Garry Manufacturing, New Brunswich, NJ; Robinson-Nugent,
New Albany, IN; and Samtec Electronic Har dware, New Albany,
IN.
For further information refer to Siemens Appnote 22.
Optical Considerations
The 0.270" high characters of the DLX3416 gives readability up
to eight feet. Proper filter selection enhances readability over
this distance.
Filters enhance the contrast ratio between a lit LED and the
character background intensifying the discrimination of differ-
ent characters. The only limitation is cost. Take into consider-
ation the ambient lighting environment for the best cost/benefit
ratio for filters.
Incandescent (with almost no green) or fluor escent (with almost
no red) lights do not have the flat spectral r esponse of sunlight.
Plastic band-pass filters are an inexpensive and effective way
to strengthen contrast ratios.
The DLR3416 is a standard r ed display and should be matched
with long wavelength pass filter in the 600 nm to 620 nm range.
The DLO3416 is a high efficiency red display and should be
matched with a long wavelength pass filter in the 470 nm to 590
range. The DLG3416 should be matched with a yellow-green
band-pass filter that peaks at 565 nm. For displays of multiple
colors, neutral density gray filters offer the best compromise.
Additional contrast enhancement is gained by shading the dis-
plays. Plastic band-pass filters with built-in louvers offer the
next step up in contrast improvement. Plastic filters can be
improved further with anti-reflective coatings to reduce glare.
The trade-off is fuzzy characters. Mounting the filters close to
the display reduces this effect. Take care not to overheat the
plastic filter by allowing for proper air flow.
Optimal filter enhancements are gained by using circular polar-
ized, anti-reflective, band-pass filters. Circular polarizing further
enhances contrast by reducing the light that travels thr ough the
filter and relfects back off the display to less than 1%.
Several filter manufacturers supply quality filter materials.
Some of them are: Panelgraphic Corporation, W. Caldwell, NJ;
SGL Homalite, Wilmington, DE; 3M Company, Visual Products
Division, St. Paul, MN; Polaroid Corporation, Polarizer Division,
Cambridge, MA; Marks Polarized Corporation, Deer Park, NY,
Hoya Optics, Inc., Fremont, CA.
One last note on mounting filters: recessing displays and bezel
assemblies is an inexpensive way to provide a shading ef fect in
overhead lighting situations. Several Bezel manufacturers are:
R.M.F. Products, Batavia, IL; Nobex Components, Griffith Plas-
tic Corp., Burlingame, CA; Photo Chemical Products of Califor-
nia, Santa Monica, CA; .E.E.-Atlas, Van Nuys, CA.
Refer to Siemens Appnote 23 for further information.