MM5452V National Semiconductor, MM5452V Datasheet - Page 6

• Manufacturer Part Number: MM5452V
• Description: LCD DISPLAY DRIVER, 5452, PLCC44
• Manufacturer: National Semiconductor

Specifications of MM5452V

• Module Configuration: CMOS
• Supply Current: 40µA
• No. Of Segments: 32
• Meter Display Type: LCD
• Supply Voltage Range: 3V To 10V
• Driver Case Style: LCC
• No. Of Pins: 44
• Operating Temperature Range: -40°C To
• No. Of Digits / Alpha: 4.1/2
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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Functional Description
*
frequency between 30 Hz and 150 Hz.
Figure 9 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
externally 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 8 , a flip-flop is used to assure
The minimum recommended value for R for the oscillator input is 9 k . An RC time constant of approximately 4.91 x 10
(Continued)
FIGURE 7. Parallel Backplane Outputs
FIGURE 8. External Backplane Clock
6
a 50% duty cycle. The oscillator input is grounded to prevent
oscillation and reduce current consumptions in the chips.
The oscillator is not used.
Using an external clock allows synchronizing the display
drive with AC power, internal clocks, or DVM integration time
to reduce interference from the display.
Figure 10 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 stair-
case voltage generated by a counter and a digital-to-analog
−4
should produce a backplane
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