HDSP-4501 HP [Agilent(Hewlett-Packard)], HDSP-4501 Datasheet - Page 8

• Manufacturer Part Number: HDSP-4501
• Description: Large 5 X 7 Dot Matrix Alphanumeric Displays 17.3/26.5 mm Character Heights
• Manufacturer: HP [Agilent(Hewlett-Packard)]

Operational Considerations
Electrical Description
These display devices are com-
posed of light emitting diodes, with
the light from each LED optically
stretched to form individual dots.
These display devices are well
suited for strobed operation. The
typical forward voltage values can
be scaled from Figure 2. These
values should be used to calculate
the current limiting resistor value
and the typical power dissipation.
Expected maximum V
driver circuit design and maximum
power dissipation, may be
calculated using the following
V
AlGaAs Red
HER (HDSP-450x):
Green (HDSP-510x):
Figure 3 allows the designer to
calculate the luminous intensity at
different peak and average
currents. The following equation
calculates intensity at different
peak and average currents:
I
SHEET)(
Where:
I
I
I
V
F
F
V
(HDSP-M10x):
F
PEAK
AVG = (I
AVG is the desired time averaged
AVG DATA SHEET is the time
LED current.
averaged data sheet test current
for I
the peak current, scaled from
Figure 3.
averaged data sheet luminous
intensity, resulting from I
DATA SHEET.
V
For I
V
For I
V
For I
V
For I
MAX models:
DATA SHEET is the time
F
F
F
F
MAX = 1.8 V + I
MAX = 2.0 V + I
MAX = 1.75 V + I
MAX = 1.75 V + I
V
is the relative efficiency at
PEAK
PEAK
PEAK
PEAK
DATA SHEET.
PEAK
F
AVG/I
20 mA
20 mA
5 mA
5 mA
)(I
V
F
AVG DATA
DATA SHEET)
PEAK
PEAK
F
PEAK
PEAK
values, for
(20 )
(10 )
F
(35 )
(38 )
AVG
I
For example, what is the luminous
intensity of an AlGaAs Red (HDSP-
L10X) driven at 50 mA peak 1/5
duty factor?
I
I
I
Therefore
I
Thermal Considerations
The device thermal resistance may
be used to calculate the junction
temperature of the central LED.
The equation below calculates the
junction temperature of the central
(hottest) LED.
T
T
P
N is the number of LEDs ON per
V
R
R
R
For example, what is the maximum
ambient temperature an HDSP-
L10X can operate with the
following conditions:
V
F
F
V
V
A
F
PEAK
J
D
AVG = 50 mA * 0.2 = 10 mA
AVG DATA SHEET = 2 mA
AVG is the calculated time
AVG = (10 mA/2 mA)(0.98)
averaged luminous intensity
resulting from I
the central LED.
LED.
character.
appropriate V
resistance from the central LED
to the ambient.
resistance from the central LED
to pin.
resistance from the pin to the
ambient.
DATA SHEET = 1650 cd
(1650 cd) = 8085 cd
MAX is calculated using the
is the junction temperature of
J-A
J-PIN
PIN-A
T
P
R
is the ambient temperature.
is the power dissipated by one
J
D
J-A
= T
is the package thermal
= (V
= 0.98
is the package thermal
is the package thermal
= R
A
F
+ (P
MAX)(I
J-PIN
F
D
)(R
model.
F
+ R
AVG.
F
AVG)
J-A
PIN-A
)(N)
www.agilent.com/semiconductors
E-mail: [e-mail]
Data subject to change.
Copyright © 2004 Agilent Technologies, Inc.
Obsoletes 5988-2224EN
July 8, 2004
5988-5215EN
I
I
R
N = 35
T
V
P
T
The maximum number of dots ON
for the ASCII character set is 20.
What is the maximum ambient
temperature an HDSP-L10X can
operate with the following
conditions:
I
I
R
N = 20
T
V
P
T
Therefore, the maximum ambient
temperature can be increased by
reducing the average number of
dots ON from 35 to 20 dots ON per
display.
Contrast Enhancement
For information on contrast
enhancement, please see
Application Note 1015.
Soldering/Cleaning
For Soldering/Cleaning information
on soldering LEDs, please refer to
Application Note 1027.
For product information and a complete list of
Agilent contacts and distributors, please go to
our web site.
PEAK
F
PEAK
F
A
A
F
F
J
D
J
D
AVG = 10 mA
AVG = 10 mA
MAX = 110 C
MAX = 110 C
MAX = 2.0 V + (0.125 A)(10)
MAX = 3.25 V
J-A
= 110 C –
J-A
= 110 C –
= (3.25 V)(0.01 A)
= 0.0325 W
= 0.0325 W
= 53 C
= 77 C
(50 C/W)(0.0325 W)(35)
(50 C/W)(0.0325 W)(20)
= 50 C/W
= 50 C/W
= 125 mA
= 125 mA
= 3.25 V