STMICROELECTRONICS M5480B7

M5480
LED DISPLAY DRIVER
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3 1/2 DIGIT LED DRIVER (23 segments)
CURRENT GENERATOR OUTPUTS (no resistors required)
CONTINUOUS BRIGHTNESS CONTROL
SERIAL DATA INPUT
NO LOAD SIGNAL REQUIRED
WIDE SUPPLY VOLTAGE OPERATION
TTL COMPATIBILITY
Applications examples
MICROPROCESSOR DISPLAYS
INDUSTRIAL CONTROL INDICATION
RELAY DRIVER
INSTRUMENTATION READOUTS
DIP-28
(Plastic Package)
DESCRIPTION
The M5480 is a monolithic MOS integrated circuit
produced with a N-channel silicon gate technology.
It utilizes the M5451 die packaged in a 28-pin
plas-tic package making it ideal for a 3 1/2 digit
dispaly. A single pin controls the LED dispaly brightness by setting a reference current through a variable resistor connected either to VDD or to a
separate supply of 13.2V maximum.
The M5480 is a pin-to-pin replacement of the NS
MM 5480.
ORDER CODE : M5480B7
May 1993
V SS
1
28
OUTPUT BIT 12
OUTPUT BIT 11
2
27
OUTPUT BIT 13
OUTPUT BIT 10
3
26
OUTPUT BIT 14
OUTPUT BIT 9
4
25
OUTPUT BIT 15
OUTPUT BIT 8
5
24
OUTPUT BIT 16
OUTPUT BIT 7
6
23
OUTPUT BIT 17
OUTPUT BIT 6
7
22
OUTPUT BIT 18
OUTPUT BIT 5
8
21
OUTPUT BIT 19
OUTPUT BIT 4
9
20
OUTPUT BIT 20
OUTPUT BIT 3
10
19
OUTPUT BIT 21
OUTPUT BIT 2
11
18
OUTPUT BIT 22
OUTPUT BIT 1
12
17
OUTPUT BIT 23
BRIGHTNESS CONTROL
13
16
DATA IN
V DD
14
15
CLOCK IN
5480-01.EPS
PIN CONNECTIONS
1/6
M5480
BLOCK DIAGRAM (Figure 1)
V DD
BRITGHTNESS
CONTROL
14
13
OUTPUT
BIT 23
OUTPUT
BIT 1
17
12
35 OUTPUT BUFERS
1nF
LOAD
35 LATCHES
SERIAL
DATA
16
CLOCK
15
35 BIT SHIFT REGISTER
5480-02.EPS
RESET
1
Symbol
VDD
VI
VO (off)
IO
Ptot
Tj
Toper
Tstg
Parameter
Supply Voltage
Input Voltage
Off State Output Voltage
Output Sink Current
Total Package Power Dissipation at 25 °C
at 85 °C
Junction Temperature
Operating Temperature Range
Storage Temperature Range
Value
– 0.3 to 15
– 0.3 to 15
15
40
940
490
150
– 25, + 85
– 65, + 150
Unit
V
V
V
mA
mW
mW
°C
°C
°C
Stresses in excess of those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only
and functional operation of the device at these or any other conditions in excess of those indicated in the operational sections of this specification
is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
2/6
5480-01.TBL
ABSOLUTE MAXIMUM RATINGS
M5480
Symbol
Parameter
Supply Voltage
VDD
IDD
Supply Current
Input Voltages Logical "0" Level
VI
Logical "1" Level
IB
VB
VO(off)
IO
Brightness Input Current (note 2)
Brightness Input Voltage (pin 13)
Off State Output Voltage
Output Sink Current (note 3)
Segment OFF
Segment ON
fclock
IO
Test Conditions
Min.
4.75
VDD = 13.2 V
± 10 µA Input Bias
4.75 ≤ VDD ≤ 5.25
VDD > 5.25
Input Current = 750µA, Tamb = 25oC
– 0.3
2.2
VDD – 2
0
3
13.2
VO = 3 V
VO = 1 V (note 4)
Brightness In. = 0 µA
Brightness In. = 100 µA
Brightness In. = 750 µA
0
2
12
0
Input Clock Frequency
Output Matching (note 1)
Notes : 1.
2.
3.
4.
Typ.
2.7
15
Max.
13.2
7
0.8
VDD
VDD
0.75
4.3
18
Unit
V
mA
V
V
V
mA
V
V
10
µA
10
4
25
0.5
± 20
µA
mA
mA
MHz
%
5480-02.TBL
STATIC ELECTRICAL CHARACTERISTICS
(Tamb within operating range, VDD = 4.75V to 13.2V, VSS = 0V,unless otherwise specified)
Output matching is calculated as the percent variation from IMAX + IMIN/2.
With a fixed resistor on the brightness input some variation in brightness will occur from one device to another.
Absolute maximum for each output should be limited to 40 mA.
The VO voltage should be regulated by the user
FUNCTIONAL DESCRIPTION
The M5480 is specifically designed to operate 3 1/2
digit alphanumeric displays with minimal interface
with the display and the data source. 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 complete, thus providing nonmultiplexed, direct drive to the display.
Outputs change only if the serial data bits differ
from the previous time.
Display brightness is determined by control of the
output current for LED displays. A 1nF capacitor
should be connected to brightness control, pin 13,
to prevent possible oscillations.
A block diagram is shown in Figure 1. The output
current is typically 20 times greater than the current
into pin 13, which is set by an external variable
resistor.
There is an internal limiting resistor of 400 Ω nominal value.
Figure 2 shows the input data format. A start bit of
logical "1" precedes 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-slave configurations. There is no clear for the
master portion of the first register, thus allowing
continuous operation.
Figure 2 : Input Data Format
1
36
CLOCK
START
BIT 1
BIT 34
BIT 35
DATA
5480-03.EPS
LOAD
(INTERNAL)
RESET
(INTERNAL)
3/6
M5480
There must be a complete set of 36 clocks or the
shift registers will not clear.
When power is first applied to the chip an internal
power ON reset signal is generated which resets
all registers and all latches. The START bit and the
first clock return the chip to its normal operation.
Figure 3 shows the timing relationships between
Data, and Clock. A maximum clock frequency of
0.5MHz is assumed.
Figure 4 shows the Output Data Format for the
M5480. Because it uses only 23 of the possible
35 outputs, 12 of the bits are "Don’t Care".
For applications where a lesser number of outputs
are used, it is possible to either increase the current
per output, or operate the part at higher than 1V
VOUT.
The following equation can be used for calculations.
Tj = [ (VOUT) (ILED) (No.of segments) + VDD . 7 mA
] (132 °C/W) + Tamb
where:
Tj = junction temperature (150 °C max)
VOUT = the voltage at the LED driver outputs
ILED = the LED current
132 °C/W = thermal coefficient of the package
Tamb = ambient temperature
Figure 3
DATA
300ns (min.)
5480-04.EPS
CLOCK
5451
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
START
5480
X
23
22
21
20
19
X
X
18
X
17
16
15
14
13
12
X
START
5451
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
START
5480
X
X
X
11
10
9
8
X
X
X
7
6
5
4
3
2
1
X
START
TYPICAL APPLICATION
5480-03.TBL
Figure 4 : Serial Data Bus / Outputs Correspondance
+V C
a)
BASIC 3 1/2 Digit Interface.
R
ID
VD
23 SEGMENTS
5480-06.EPS
V OUT
M5480
CLOCK
DATA
POWER DISSIPATION OF THE IC
The power dissipation of the IC can be limited using
different configurations.
4/6
5480-05.EPS
DISPLAY DRIVER
In this application R must be chosen taking into
account the worst operating conditions.
R is determined by the maximum number of segments activated.
VC − VD MAX − VOUT MIN
R=
NMAX ⋅ ID
M5480
The worst case condition for the device is when
roughly half of the maximum number of segments
are activated.
It must be checked that the total power dissipation
does not exceed the absolute maximum ratings of
the device.
In critical cases more resistors can be used in
conjunction with groups of segments.
In this case the current variation in the single
resistor is reduced and Ptot limited.
c)
+V C
+VC
5480-08.EPS
V OUT +V D
5480-07.EPS
b)
In this configuration the drop on the serial connected diodes is quite stable if the diodes are
properly chosen.
The total power dissipation of the IC depends, in a
first approximation, only on the number of segments activated.
In this configuration VOUT + VD is constant. The total
power dissipation of the IC depends only on the
number of segments activated.
5/6
M5480
I
L
a1
PACKAGE MECHANICAL DATA
28 PINS - PLASTIC DIP
b1
b
b2
e
E
e3
D
15
1
14
a1
b
b1
b2
D
E
e
e3
F
i
L
Min.
Millimeters
Typ.
0.63
0.45
0.23
Max.
Min.
0.31
0.009
1.27
Max.
0.012
0.050
37.4
16.68
15.2
Inches
Typ.
0.025
0.018
1.470
0.657
0.598
2.54
33.02
0.100
1.300
14.1
4.445
3.3
0.555
0.175
0.130
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility
for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result
from its use. No licence is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics.
Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all
information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life
support devices or systems without express written approval of SGS-THOMSON Microelectronics.
© 1994 SGS-THOMSON Microelectronics - All Rights Reserved
Purchase of I2C Components of SGS-THOMSON Microelectronics, conveys a license under the Philips
I2C Patent. Rights to use these components in a I2C system, is granted provided that the system conforms to
the I2C Standard Specifications as defined by Philips.
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6/6
DIP28.TBL
Dimensions
PM-DIP28.EPS
F
28