MM5452N/NOPB National Semiconductor, MM5452N/NOPB Datasheet - Page 6

• Manufacturer Part Number: MM5452N/NOPB
• Description: IC DRIVER LIQ CRYSTL DISP 40-DIP
• Manufacturer: National Semiconductor

Specifications of MM5452N/NOPB

• Display Type: LCD
• Configuration: 7 Segment + DP, Alphanumeric & Bar Graph
• Interface: Serial
• Digits Or Characters: 4.5 Digits
• Voltage - Supply: 3 V ~ 10 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Other names: *MM5452N; *MM5452N/NOPB; MM5452N

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*The minimum recommended value for R for the oscillator input is 9 kΩ. An RC time constant of approximately 4.91 × 10
between 30 Hz and 150 Hz.
Figure 7 shows a four wire remote display that takes advan-
tage of the device’s serial input to move many bits of display
information on a few wires.
USING AN EXTERNAL CLOCK
The MM5452/MM5453 LCD Drivers can be used with an ex-
ternally supplied clock, provided it has a duty cycle of 50%.
Deviations from a 50% duty cycle result in an offset voltage
on the LCD. In Figure 6, a flip-flop is used to assure a 50%
duty cycle. The oscillator input is grounded to prevent oscil-
lation and reduce current consumptions in the chips. The
oscillator is not used.
FIGURE 5. Parallel Backplane Outputs
FIGURE 6. External Backplane Clock
6
Using an external clock allows synchronizing the display drive
with AC power, internal clocks, or DVM integration time to re-
duce interference from the display.
Figure 8 is a general block diagram that shows how the
device’s serial input can be used to advantage in an analog
display. The analog voltage input is compared with a staircase
voltage generated by a counter and a digital-to-analog con-
verter or resistor array. The result of this comparison is
clocked into the MM5452, MM5453. The next clock pulse in-
crements the staircase and clocks the new data in.
−4
should produce a backplane frequency
613707
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