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M5482
Table 2. Static Electrical Characteristics
(T
amb
within operating range, V
DD
= 4.75V to 13.2V, V
SS
= 0V, unless otherwise specified)
Note: 1. Output matching is calculated as the percent variation from I
MAX
+ I
MIN
/2.
2. With a fixed resistor on the brightness input some variation in brightness will occur from one device to another.
3. Absolute maximum for each output should be limited to 40mA.
4. The V
O
voltage should be regulated by the user.
FUNCTIONAL DESCRIPTION
The M5482 uses the M5451 die which is packaged
to operate 2-digit alphanumeric displays with min-
imal interface with the display and the data source.
Serial data transfer from the data source to the dis-
play driver is accomplished with 2 signals, serial
data and clock. Using a format of a leading "1" fol-
lowed by the 35 data bits allows data transfer with-
out an additional load signal.
The 35 data bits are latched after the 36th bit is
complete, thus providing non-multiplexed, direct
drive to the display. Outputs change only if the se-
rial 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 9, to pre-
vent possible oscillations.
A block diagram is shown in Figure 3. The output
current is typically 20 times greater than the cur-
rent into Pin 9, which is set by an external variable
resistor.
There is an internal limiting resistor of 400Ω nom-
inal value.
Figure 4 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.
Symbol Parameter Test Conditions Min. Typ. Max. Unit
V
DD
Supply Voltage 4.75 13.2 V
I
DD
Supply Current
V
DD
= 13.2V
7mA
V
I
Input Voltage Logical "0" Level ± 10µA Input Bias - 0.3 0.8 V
Logical "1" Level
4.75 ≤ V
DD
≤ 5.25
2.2
V
DD
V
V
DD
> 5.25 V
DD
- 2 V
DD
V
I
B
Brightness Input Current (note 2) 0 0.75 mA
V
B
Brightness Input Voltage (pin 9)
Input Current = 750µA, T
amb
= 25°C
34.3V
V
O(off)
Off State Out. Voltage 13.2 V
I
O
Out. Sink Current (note 3)
Segment OFF
V
O
= 3V
10 µA
Segment ON
V
O
= 1V (note 4)
Brightness In. = 0µA010µA
Brightness In. = 100µA22,74mA
Brightness In. = 750µA121525mA
f
clock
Input Clock Frequency 0 0.5 MHz
I
O
Output Matching (note 1) ± 20 %
