M5481B7 STMicroelectronics, M5481B7 Datasheet - Page 4

• Manufacturer Part Number: M5481B7
• Description: IC LED DISPLAY DRIVER 20-PDIP
• Manufacturer: STMicroelectronics

Specifications of M5481B7

• Display Type: LED
• Configuration: 7 Segment
• Interface: Serial
• Digits Or Characters: 2 Digits
• Current - Supply: 7mA
• Voltage - Supply: 4.5 V ~ 13.2 V
• Operating Temperature: -25°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 20-DIP (0.300", 7.62mm)
• Number Of Digits: 2
• Number Of Segments: 14
• Operating Supply Voltage: 4.5 V to 13.2 V
• Maximum Supply Current: 7 mA
• Maximum Power Dissipation: 1.5 W
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

M5481
Figure 4. Input Data Format
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 shift register, thus al-
lowing continuous operation.
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 reset the chip to its normal operation.
Figure 5 shows the timing relationships between
Data, Clock and DATA ENABLE.
A maximum clock frequency of 0.5MHz is as-
sumed.
Table 3 shows the Output Data Format for the
M5481. Because it uses only 14 of the possible
outputs, 21 of the bits (including bit 35 which was
already unused in the M5450) are “Don’t Cares” .
For applications where a lesser number of outputs
are used it is possible to either increase the cur-
rent per output or operate the part at higher than
1V V
The following equation can be used for calcula-
tions.
Table 3. Serial Data Bus / Outputs Correspondance
4/10
5451
5481
5450
5481
out
CLOCK
DATA
LOAD
(INTERNAL)
RESET
(INTERNAL)
.
35
17
X
X
34
X
16
8
33
X
15
7
32
X
START
1
14
6
31
X
13
5
BIT 1
30
14
12
X
29
13
11
X
28
X
10
X
27
X
X
9
26
X
T
x (80°C/W) + T
where:
T
V
I
80°C/W = thermal coefficient of the package
T
Figure 5.
LED
CLOCK
DATA
DATA ENABLE
j
j
amb
out
= [(V
= junction temperature (150°Cmax)
8
4
25
= voltage at the LED driver outputs
X
= LED current
= ambiant temperature
out
7
3
24
12
) (I
LED
6
2
23
11
amb
BIT 34 BIT 35
) (No. of segments) + V
5
1
22
10
36
X
4
21
9
X
3
20
X
100ns (min.)
19
X
2
X
300ns (min.)
18
X
X
1
DD
START
START
START
START
x 7mA]