HDLO-2416 データシートの表示（PDF） - Broadcom Corporation
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HDLO-2416 Datasheet PDF : 18 Pages
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HDLx-2416 Series
Data Sheet
Figure 3 Intensity Modulation Control using an Astable
Multivibrator (reprinted with permission from Electronics
magazine, Sept.19, 1974, VNU Business pub. Inc.)
+ VDD
1k
1N914
8
4
7
3 BL
(PIN 18)
1k
555
10 kHz
OUTPUT
6
250 k
2
1
LOG
400 pF
package. This package construction makes the display highly
tolerant to temperature cycling and allows wave soldering.
The inputs to the CMOS IC are protected against static
discharge and input current latchup. However, for best results
standard CMOS handling precautions should be used. Prior to
use, the HDLX-2416 should be stored in anti-static tubes or
conductive material. During assembly a grounded conductive
work area should be used, and assembly personnel should
wear conductive wrist straps. Lab coats made of synthetic
material should be avoided since they are prone to static
charge build-up.
Input current latchup is caused when the CMOS inputs are
subjected either to a voltage below ground (Vin < ground) or
to a voltage higher than VDD (Vin > VDD) and when a high
current is forced into the input. To prevent input current
latchup and ESD damage, unused inputs should be connected
either to ground or to VDD. Voltages should not be applied to
the inputs until VDD has been applied to the display. Transient
input voltages should be eliminated.
Figure 3 shows a circuit designed to dim the display from 98%
to 2% by pulse width modulating the BL input. A logarithmic or
a linear potentiometer may be used to adjust the display
intensity. However, a logarithmic potentiometer matches the
response of the human eye and therefore provides better
resolution at low intensities. The circuit frequency should be
designed to operate at 10 kHz or higher. Lower frequencies
may cause the display to flicker.
Extended Function Disable
Extended Function Disable (bit D6 of the Control Register)
disables the extended blanking and dimming functions in the
HDLX-2416. If the Extended Function Disable is a logic 1, the
internal brightness control, Master Blank, and Digit Blank
Disable bits are ignored. However the BL input and Cursor
control are still active. This allows downward compatibility to
the HPDL-2416.
Mechanical and Electrical Considerations
The HDLX-2416 is an 18 pin DIP package that can be stacked
horizontally and vertically to create arrays of any size. The
HDLX-2416 is designed to operate continuously from –40°C to
+85°C for all possible input conditions.
The HDLX-2416 is assembled by die attaching and wire
bonding 140 LEDs and a CMOS IC to a high temperature
printed circuit board. A polycarbonate lens is placed over the
PC board creating an air gap environment for the LED wire
bonds. Backfill epoxy environmentally seals the display
Soldering and Post Solder Cleaning
Instructions for the HDLX-2416
The HDLX-2416 may be hand soldered or wave soldered with
SN63 solder. When hand soldering it is recommended that an
electronically temperature controlled and securely grounded
soldering iron be used. For best results, the iron tip
temperature should be set at 315°C (600°F). For wave soldering,
a rosin-based RMA flux can be used. The solder wave
temperature should be set at 245°C ±5°C (473°F ±9°F), and
dwell in the wave should be set between 1.5 to 3 seconds for
optimum soldering. The preheat temperature should not
exceed 110°C (230°F) as measured on the solder side of the PC
board.
For further information on soldering and post solder cleaning,
see Application Note 1027, Soldering LED Components.
Contrast Enhancement
The objective of contrast enhancement is to provide good
readability in the end user’s ambient lighting conditions. The
concept is to employ both luminance and chrominance
contrast techniques. These enhance readability by having the
OFF-dots blend into the display background and the ON-dots
vividly stand out against the same background. For additional
information on contrast enhancement, see Application Note
1015.
Broadcom
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