3-247
Figure 3. Peak Column Current vs
Column Voltage.
Figure 2. Relative Luminous Intensity
vs Ambient Temperature.
Figure 1. Maximum Allowable Power
Dissipation vs Ambient Temperature
as a Function of Thermal Resistance
Junction-to-Ambient, RθJ-A. Derated
Operation Assumes RθPC-A = 35°C/W
per Display for Printed Circuit Board.
TJ (IC) MAX = 130°C.
RθJ-A (TA = 100°C)
= 22°C/W for HCMS-235X Series
= 32°C/W for HCMS-231X Series
= 38°C/W for HCMS-201X Series.
Electrical Description
Each display device contains four
5 x 7 LED dot matrix characters
and two CMOS integrated
circuits, as shown in Figure 4.
The two CMOS integrated circuits
form an on-board 28 bit serial-in-
parallel-out shift register that will
accept standard TTL logic levels.
The Data Input, pin 12, is
connected to bit position 1 and
the Data Output, pin 7, is
connected to bit position 28. The
shift register outputs control
constant current sinking LED row
drivers. The nominal current sink
per LED driver is 11 mA for the
HCMS-201X displays, 13 mA for
the HCMS-231X displays and
18 mA for the HCMS-235X
displays. A logic 1 stored in the
shift register enables the
corresponding LED row driver
and a logic 0 stored in the shift
register disables the
corresponding LED row driver.
The electrical configuration of
these CMOS IC alphanumeric
displays allows for an effective
interface to a display controller
circuit that supplies decoded
character information. The row
data for a given column (one 7 bit
byte per character) is loaded (bit
serial) into the on-board 28 bit
shift register with high to low
transitions of the Clock input. To
load decoded character informa-
tion into the display, column data
for character 4 is loaded first and
the column data for character 1 is
loaded last in the following
manner. The 7 data bits for
column 1, character 4, are loaded
into the on-board shift register.
Next, the 7 data bits for column
1, character 3, are loaded into the
shift register, shifting the charac-
ter 4 data over one character
position. This process is repeated
for the other two characters until
all 28 bits of column data (four 7
bit bytes of character column
data) are loaded into the on-
board shift register. Then the
column 1 input, VCOL pin 1, is
energized to illuminate column 1
in all four characters. This
process is repeated for columns
2, 3, 4 and 5. All VCOL inputs
should be at logic low to insure
the display is off when loading
data. The display will be blanked
when the blanking input VB, pin
8, is at logic low regardless of the
outputs of the shift register or
whether one of the VCOL inputs is
energized.
Refer to Application Note 1016
for drive circuit information.
ESD Susceptibility
The HCMS-201X/-231X/-235X
series displays have an ESD
susceptibility ratings of CLASS 3
per DOD-STD-1686 and CLASS B
per MIL-STD-883C. It is
recommended that normal CMOS
handling precautions be observed
with these devices.
Soldering and Post Solder
Cleaning
These displays may be soldered
with a standard wave solder
process using either an RMA flux
and solvent cleaning or an OA
flux and aqueous cleaning. For