PDSP2110, PDSP2111, PDSP2112, PDSP2113, PDSP2114

2006-01-23

13

Electrical and Mechanical Considerations

Voltage Transient Suppression

For best results power the display and the components that inter-

face with the display to avoid logic inputs higher than V

tionally, the LEDs may cause transients in the power supply line

while they change display states. The common practice is to place

a parallel combination of a 0.01 µF and a 22 µF capacitor between

V

ESD Protection

The input protection structure of the PDSP2110/1/2/3/4 provides

significant protection against ESD damage. It is capable of with-

standing discharges greater than 2.0 kV. Take all the standard pre-

cautions, normal for CMOS components. These include properly

grounding personnel, tools, tables, and transport carriers that come

in contact with unshielded parts. If these conditions are not, or can-

not be met, keep the leads of the device shorted together or the

parts in anti-static packaging.

Soldering Considerations

The PDSP2110/1/2/3/4 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 rosin-based RMA flux without

alcohol can be used.

Wave temperature of 245°C ± 5°C with a dwell between 1.5 sec. to

3.0 sec. Exposure to the wave should not exceed temperatures

above 260°C for five seconds at 1.59 mm (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. Exercise care in choos-

ing solvents as some may chemically attack the nylon package.

Maximum exposure should not exceed two minutes at elevated

temperatures. Acceptable solvents are TF (trichorotrifluorethane),

TA, 111 Trichloroethane, and unheated acetone.

(1)

Note:

1)

Acceptable commercial solvents are: Basic TF, Arklone, P.

Genesolv, D. Genesolv DA, Blaco-Tron TF and Blaco-Tron 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 manufac-

turers are: Allied Chemical Corporation, Specialty Chemical Divi-

sion, Morristown, NJ; Baron-Blakeslee, Chicago, IL; Dow

Chemical, Midland, MI; E.I. DuPont de Nemours & Co., Wilming-

ton, DE.

For further information refer to Appnotes 18 and 19 at

www.osram-os.com

An alternative to soldering and cleaning the display modules is to

use sockets. Naturally, 28 pin DIP sockets 15.24 mm (0.600") wide

with 2.54 mm (0.100") centers work well for single displays.

Multiple display assemblies are best handled by longer SIP sock-

ets or DIP sockets when available for uniform package alignment.

Socket manufacturers are Aries Electronics, Inc., Frenchtown, NJ;

Garry Manufacturing, New Brunswick, NJ; Robinson-Nugent, New

Albany, IN; and Samtec Electronic Hardward, New Albany, IN.

For further information refer to Appnote 22 at www.osram-os.com

Optical Considerations

The 5.10 mm (0.200") high character of the PDSP211X gives read-

ability up to eight 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 discrimination of

different 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 fluorescent (with almost no

red) lights do not have the flat spectral response of sunlight. Plas-

tic band-pass filters are an inexpensive and effective way to

strengthen contrast ratios. The PDSP2110/2112 are red/super-red

displays and should be matched with long wavelength pass filter in

the 570 nm to 590 nm range. The PDSP2111/2113/2114 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 Homa-

lite, 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 Plastic

Corp., Burlingame, CA; Photo Chemical Products of California,

Santa Monica, CA; I.E.E.–Atlas, Van Nuys, CA.