9-201
DISPLAYS
0.54" 2-Character 14-Segment
Alphanumeric LED Displays
With MOS I.C. Driver
LTM-8647A Series
Package DimensionsFeatures
0.54 inch (13.8mm) digit height, 14-segment character.
Wide supply voltage operation.
Serial data input.
Constant Current drivers.
Continuous brightness control.
Solid state reliability, long operation life.
Wide viewing angle.
Choices of five bright colors-yellow/bright-red/green/
red orange/high efficiency red.
TTL compatible.
Description
The LTM-8647A series are dual character 14-segment
alphanumeric display modules, having a built-in M5450
MOS integrated circuits. The integrated circuit contains
serial data input, 35 bit shift registers. 34 LED driver
output and a brightness control. The bright red, green
and yellow devices utilize LED chips which are made
from GaP on a transparent GaP substrate. The red or-
ange and high efficiency red devices utilize LED chips
which are made from GaAsP on a transparent GaP
substrate. The MOS integrated circuit are produced with
N-channel silicon gate technology. Bright red displays
have black face and red segments . Green, yellow and
red orange displays have gray face and white
segments. High efficiency red displays have red face
and red segments.
Notes: All dimensions are in millimeters (inches).
Tolerance : 0.25mm (0.010") unless
otherwise noted.
Devices
Part No. LTM-
Hi.-Eff. Red
Dual Character, with I.C. Driver8647AHR
Description
Green
8647AP
Red
Orange
8647AE
Bright Red
8647AY
Yellow
8647AG
Bit 32 Output
Bit 33 Output
Bit 34 Output
Data Input
Clock Input
Data Enable
VDD
VLED
Brt Control
Pin No.
1
2
3
4
5
6
7
8
9
Description
No Pin
No Pin
No Pin
Vss*1
Vss*1
No Pin
No Pin
Bit 31 Output
No Pin
Description
10
11
12
13
14
15
16
17
18
Pin No.
Pin Connection
Note:Pin no 13 & 14 are internally connected.
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Absolute Maximum Ratings at Ta=25
SymbolParameter
Supply Voltage*1
Input Voltage
Off State Output Voltage
LED Supply Voltage
Power Dissipation of IC*2
Supply Current
Operating Temperature Range
Storage Temperature Range
VDD
VI
VO(off)
VLED
PD(IC)
IDD
Top
Tstg
Min.
-0.3
-0.3
2.8
-20
-20
Max.
12
12
12
3.5
335
8.5
+60
+60
Unit
V
V
V
V
mW
mA
Note : 1. All voltages are with respect to Vss(GND)
2. Power dissipation of IC is given by PD=(VLED-VF)(IF)(No. of Segments)+(8.5mA) (VDD)
*VF is LED forward voltage.
Solder Temperature 1/16 Inch Below Seating Plane for 3 Seconds at 260
SymbolParameter
Supply Voltage
Input Voltage
Logical 0 Level
Logical 1 Level
Logical 1 Level
Brightness Input Current
Brightness Input Voltage
Off State Voltage
Output Sink Current
Segment Off
Segment On
Input Clock Frequency
Output Matching
VDD
VI
IB
VB
VO(off)
FCLOCK
IO
Min.
4.75
-0.3
2.2
VDD -2
0
3
0
Typ.
3
6
Max.
11
0.8
VDD
VDD
0.75
4.3
11
10
0.5
20
Unit
V
V
V
V
mA
V
V
A
mA
mA
MHZ
%
TestCondition
10 A Input Bias
4.75V<VDD<5.25V
VDD>5.25V
Input Current =750 A
IB=0 A
IB=100 A
IB=200 A
Recommended Operating Condition at Ta=25
Electrical/Optical Characteristics at Ta=25
LTM-8647AP
LTM-8647AG
SymbolParameter
Average Luminous Intensity
Peak Emission Wavelength
Spectral Line Half-Width
Dominant Wavelength
Luminous Intensity Matching Ratio
IV
P
d
IV-m
Min.
320
Typ.
900
697
90
657
Max.
2:1
Unit
cd
nm
nm
nm
Test
Condition
IB=0.4mA
IB=0.4mA
IB=0.4mA
IF=20mA
IB=0.4mA
SymbolParameter
Average Luminous Intensity
Peak Emission Wavelength
Spectral Line Half-Width
Dominant Wavelength
Luminous Intensity Matching Ratio
IV
P
d
IV-m
Min.
800
Typ.
2300
565
30
569
Max.
2:1
Unit
cd
nm
nm
nm
Test
Condition
IB=0.4mA
IB=0.4mA
IB=0.4mA
IF=20mA
IB=0.4mA
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9-203
DISPLAYS
LTM-8647AY
LTM-8647AE
SymbolParameter
Average Luminous Intensity
Peak Emission Wavelength
Spectral Line Half-Width
Dominant Wavelength
Luminous Intensity Matching Ratio
IV
P
d
IV-m
Min.
800
Typ.
2300
585
35
588
Max.
2:1
Unit
cd
nm
nm
nm
Test
Condition
IB=0.4mA
IB=0.4mA
IB=0.4mA
IF=20mA
IB=0.4mA
LTM-8647AHR
SymbolParameter
Average Luminous Intensity
Peak Emission Wavelength
Spectral Line Half-Width
Dominant Wavelength
Luminous Intensity Matching Ratio
IV
P
d
IV-m
Min.
800
Typ.
2300
630
40
621
Max.
2:1
Unit
cd
nm
nm
nm
Test
Condition
IB=0.4mA
IB=0.4mA
IB=0.4mA
IF=20mA
IB=0.4mA
SymbolParameter
Average Luminous Intensity
Peak Emission Wavelength
Spectral Line Half-Width
Dominant Wavelength
Luminous Intensity Matching Ratio
IV
P
d
IV-m
Min.
800
Typ.
2300
635
40
623
Max.
2:1
Unit
cd
nm
nm
nm
Test
Condition
IB=0.4mA
IB=0.4mA
IB=0.4mA
IF=20mA
IB=0.4mA
Notes: Luminous intensity is measured with a light sensor and filter combination that appoximates the CIE (Commision
Internationale De L'Eclairage)eye-response curve.
Functional Description
Serial data transfer from the data source to the display driver is accomplished with 2 signals serial data and clock.
Using a format of a leading "1" followed by the 35 data bits allows data transfer without an additional load signal.
The 35 data bits are latched after the 36th bit is completed, thus provding non multiplexed, direct drive to the display.
Output change only if the serial data bits differ from the previous time.
Brightness of display is determined by control the output current of LED display. A 1nF capacitor Should be connected
to brightness control, Pin 7 to prevent possible oscillations. The output current is typically 25 times greater than the
current into Pin 7 which is set by an external variable resistor. There is an internal limiting resistor of 400 nominal
value.
Figure 1 shows the input data format. A start bit of logical "1" preceed the 35 bits of data. At the 36th clock, a LOAD
signal is generated synchronously with the high state of the clock, which loads the 35 bits of the shift registers into
the latches. At the low state of the clock a RESET signal is generated which clears all the shift registers for the next
set of data . The shift registers are static master-salve configuration. There is no clear for master portion of the first
register, thus allowing continuous operation.
There must be a complete set of 36 clocks or the shift registers won't clear. When power is first applied to the chip,
an internal power ON, a reset signal is generated which reset all registers and all latches. The START bit and first
clock return the chip on its normal operation. Bit 1 is the first following the start bit and it will appear on the segment
A of the digit 1. A logical "1" at the input will turn on the appropriate LED. Figure 2 shows the timing relationship between
data, clock, and DATA ENABLE. A max. clock frequency of0.5MHz is assumed.
9-204
Figure 1. Internal Block Diagram Figure 2. Input Data Format
Figure 3. Timing Relationship
Table I Serial Data Input Sequence
Bit
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Digit Segment
2
2
2
2
2
2
2
2
2
2
2
2
2
2
1
1
1
A
B
C
D
E
F
G
H
K
M
N
R
S
T
A
B
C
Digit Segment
1
1
1
1
1
1
1
1
1
1
1
1
2
D
E
F
G
H
K
M
N
R
S
T
DP
DP
Pin 17
Pin 1
Pin 2
Pin 3
Bit
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
