14
10
E F G H
Electrical/Optical Characteristics at TA =25°C
HIGH EFFICIENCY RED HDSP-3530/-3531/-3533/-3536/-3730/-3731/-3733/-3736
Parameter Symbol Test Condition Min. Typ. Max. Units
I
Luminous Intensity/Segmentl3) 100mA Pk: 1 of 5 1000 2300 #,cdIv Duty Factor
(Digit Average) 20mA DC 1800 #,cd
Peak Wavelength APEAK 635 nm
Dominant Wavelength(4) Ad 626 nm
1"--'
Forward Voltage/Segment or D.P. VF IF
=
100mA 2.55 3.1 VReverse Current/Segment or D.P. IA VA
=
6V 10 ,.,.AResponse Time, Rise and Fa1l16) tr, tf 300 ns
Temperature Coefficient of VF/Segment or D.P. AVF/oC IF
=
100mA -1.1 mV/oCYELLOW HDSP-4030/-4031/-4033/-4036/-4130/-41311-4133/-4136
Parameter Symbol Test Condillon Min. Typ. Mall. Units
Luminous Intensity/SegmentI3) 100mA Pk: 1 of 5 1000 2700 /Lcd
Iv Duty Factor
(Digit Average) 20mA DC 2100 ,.,.cd
Peak Wavelength APEAK 583 nm
Dominant WavelengthI4•5)
Ad
585 nmForward Voltage/Segment or D.P. VF IF = 100mA 2.6 3.1 V
Reverse Current/Segment or D.P. IA VA
=
6Y 10 /LAResponse Time, Rise and Fa1l16) tr, tf 200 ns
Temperature Coefficient of VF/Segment or D.P. ::"YF/oC IF = 100mA -1.1 mV;oC NOTES:
3. The digits are categorized for luminous intensity with the intensity category designated by a letter located on the right hand side of the package.
4. The dominant wavelength, Ad. is derived from the CIE chromaticity diagram and is that single wavelength which defines the color of the device.
5. The HDSP-4030/-4130 series yellow displays are categorized as to dominant wavelength with the category designated by a number adjacent to the intensity category letter.
6. The rise and fall times are for a 10'10-90% change of light intensity to a step change in current.
Operational Considerations
ELECTRICAL
The HDSP-3530/3730/4030/4130 series of display devices are composed of eight light emitting diodes, with the light from each LED optically stretched to form individual segments and a decimal point. The LEDs have a large area P-N junction diffused into a GaAsP epitaxial layer on a GaP transparent substrate.
These display devices are designed for strobed operation at high peak currents. The typical forward voltage values, scaled from Figure 4, should be used for calculating the current limiting resistor values and typical power dissipation. Expected maximum VF values forthe purpose of driver circuit design and maximum power dissipation may be calculated using the following VF models:
VF = 2.0V
+
IPEAK (110) For IPEAK ~ 30mA VF = 1.9V+
loc (140)For 10mA ::; loc ::; 30mA
Temperature derated strobed operating conditions are obtained from Figures 1 and 2. Figure 1 relates pulse duration (tp), refresh rate (f), and the ratio of maximum peak current to maximum dc current (JPEAK MAX/loc MAX)' Figure 2 presents the maximum allowed dc c'urrent vs. ambient temperature. To most effectively use Figures 1 and 2, perform the following steps:
3. Enter Figure 1 at the calculated tp. Move vertically to the refresh rate line and record the corresponding value of IPEAK MAX/I DC MAX.
Example: IPEAK MAX = (4.m (25mA) = 100mA peak.IAVG
= (1/5) (100mA) = 20mA average.
The above calculations determine the maximum allowed strobing conditions. Operation at a reduced peak current and/or pulse width may be desirable to adjust display light output to match ambient light level or to reduce power dissipation to insure even more reliable operation.
Refresh rates of 1 kHz or faster provide the most efficient operation resulting in the maximum possible time average luminous intensity.
The time average luminous intensity may be calculated using the relative efficiency characteristic of Figure 3, IJIPEAK' and adjusted for operating ambient temperature.
The time average luminous intensity at TA=25°C is calculated as follows:
I = [IAVG ] [IJIPEAK] [Iv DATA SHEET]
v TIME AVG 20mA
Example: For HDSP-4030 series IJIPEAK = 1.00 at IPEAK = 100mA
_ [20mAJ [1.00] [ 2.7mcd ] = 2.7mcd/
Iv TIME AVG - 20mA segment
The time average luminous intensity may be adjusted for operating ambient temperature by the following exponen-tial equation:
Iv (TA) = Iv (25°C) e[K ITA - 250cB
Device K
-3530/3730 Series -0.0131/oC -4030/4130 Series -0.0112/oC
Example: Iv (70°C) = (2.7mcd) e[-0.0112 170-25U= 1.63mcd/
segment
CONTRAST ENHANCEMENT
The objective of contrast enhancement is to provide good display readability in the end use ambient light. The concept is to employ luminance contrast techniques to enhance readability by having the off-segments blend into the display background and have the on-segments stand out vividly against this same background. Therefore, these display devices are assembled with a gray package and untinted encapsulating epoxy in the segments.
Contrast enhancement in bright ambients may be achieved by using a neutral density gray filter such as Panelgraphic Chromafilter Gray 10. Additional contrast enhancement may be achieved by using the neutral density 3M Light Control Film (louvered filterl.
MECHANICAL
These devices are constructed utilizing a lead frame in a standard DIP package. The LED dice are attached directly to the lead frame. Therefore, the cathode leads are the direct thermal and mechanical stress paths to the LED dice. The absolute maximum allowed junction tempera-ture, TJ MAX, is 100°C. The maximum power ratings have been established so that the worst case VF device does not exceed this limit. For most reliable operation, it is recommended that the device pin-to-ambient thermal resistance through the PC board be less than 320° C/W per segment. This will then establish a maximum thermal resistance LED junction-to-ambient of 602° C/W per segment.
To optimize device optical performance, specially developed plastics are used which restrict the solvents that may be used for cleaning. It is recommended that only mixtures of Freon (F113) and alcohol be used for vapor cleaning processes, with an immersion time in the vapors of less than two (2) minutes maximum. Some suggested vapor cleaning solvents are Freon TE, Genesolv DI-15 or DE-15, Arklone A or K. A 60°C (140°F) water cleaning process may also be used, which includes a neutralizer rinse (3% ammonia solution or equivalent), a surfactant rinse (1% detergent solution or equivalent), a hot water rinse and a thorough air dry. Room temperature cleaning may be accomplished with Freon T -E35 or T -P35, Ethanol, Isopropanol or water with a mild detergent.
« E
Figure 1. Maximum Allowed Peak Current vs. Pulse Duration.
40 per Segment vs. Ambient Temperature.
120
i I II
HDSP-3530!3730 SERIES ,
100 ! ; \
-j
/I
HDsP403OI41~! ...t I I
11.5 2.0 2.5 3.0 3.4
VF - PEAK FORWARD VOLTAGE - V
Figure 4. Peak Forward Segment Current vs.
Peak Forward Voltage.
~
/
HDse·4030/4130 SERI ES1/ I
Figure 3. Relative Elliciency (Luminous Intensity per Unit Current) vs. Peak
Figure 5. Relative Luminous Intensity vs. DC Forward Current.