HDLX-2416 查看數據表（PDF） - Avago Technologies
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HDLX-2416 Datasheet PDF : 12 Pages
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+ VDD
1k
1N914
8
4
7
3 BL
(PIN 18)
1k
555
10 kHz
OUTPUT
6
250 k
2
1
LOG
400 pF
Figure 4. Intensity modulation control using an astable multivibrator
(reprinted with permission from Electronics magazine, Sept. 19, 1974,
VNU Business pub. Inc.)
Figure 4 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 po-
tentiometer 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 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.
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 recom-
mended 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 1/2 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 Com-
ponents.
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 chromi-
nance 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 back-
ground. For additional information on contrast enhance-
ment, see Application Note 1015.
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