2000 Infineon Technologies Corp. • Optoelectronics Division • San Jose, CA SCDQ5541/5542/5543/5544/P/Q/R
www.infineon.com/opto • 1-888-Infineon (1-888-463-4636)
ESD Protection
The input protection structure of the SCDQ554XX provides sig-
nificant protection against ESD damage. It is capable of with-
standing discharges greater than 2.0 kV. Take all the standard
precautions, normal for CMOS components. These include
properly grounding personnel, tools, tables, and transport carri-
ers that come in contact with unshielded parts. If these condi-
tions are not, or cannot be met, keep the leads of the device
shorted together or the parts in anti-static packaging.
Soldering Considerations
The SCDQ554XX can be hand soldered with SN63 solder using
a grounded iron set to 260°C.
Wave soldering is also possible following these conditions: Pre-
heat that does not exceed 93°C on the solder side of the PC
board or a package surface temperature of 85°C. Water soluble
organic acid flux (except carboxylic acid) or resin-based RMA
flux without alcohol can be used.
Wave temperature of 245°C ±5°C with a dwell between 1.5 s
to 3.0 s. 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.
The SCDQ554XR connects to an external connector receptacle
which may be soldered before inserting the SCDQ554XR Dis-
play. In this way, only the connector is subject to the user’s sol-
dering process. The Molex 52418-0510 receptacle called out in
the product drawing can be used in solder reflow processes.
See Molex for specifications.
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 accept-
able. Do not use commercial dishwasher detergents.
For faster cleaning, solvents may be used. Exercise care in
choosing solvents as some may chemically attack the nylon
package. For further information refer to Appnotes 18 and 19 at
www.infineon.com/opto or in the current Infineon Optoelec-
tronic Data Book. See Appnote 19, Table 2, “Displays–
Group 2”.
Optical Considerations
The 0.123" high character of the SCDQ554XX gives readability
up to five feet. Proper filter selection enhances readability over
this distance.
Using filters emphasizes the contrast ratio between a lit LED
and the character background. This will increase the discrimina-
tion of different characters. The only limitation is cost. Take into
consideration the ambient lighting environment for the best
cost/benefit ratio for filters.
Incandescent (with almost no green) or fluorescent (with
almost no red) lights do not have the flat spectral response of
sunlight. Plastic band-pass filters are an inexpensive and effec-
tive way to strengthen contrast ratios. The SCDQ5542X is a
high efficiency red display and should be matched with long
wavelength pass filter in the 570 nm to 590 nm range. The
SCDQ5541X/3X/4X should be matched with a yellow-green
band-pass filter that peaks at 565 nm. For displays of multiple
colors, neutral density grey 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. The circular polarizing fur-
ther enhances contrast by reducing the light that travels through
the filter and reflects 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 effect 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; I.E.E.-Atlas, Van Nuys, CA.