Datasheet MM5452, MM5453 Datasheet (National Semiconductor)

MM5452/MM5453 Liquid Crystal Display Drivers

Y

General Description

The MM5452 is a monolithic integrated circuit utilizing
CMOS metal gate, low threshold enhancement mode devic­es. It is available in a 40-pin molded package. The chip can
drive up to 32 segments of LCD and can be paralleled to
increase this number. The chip is capable of driving a 4 (/2­digit 7-segment display with minimal interface between the
display and the data source.

The MM5452 stores display data in latches after it is
clocked in, and holds the data until new display data is re­ceived.

Features

Y

Serial data input

Y

No load signal required

Block Diagram

DATA ENABLE (MM5452)

Y

Wide power supply operation

Y

TTL compatibility

Y

32 or 33 outputs

Y

Alphanumeric and bar graph capability

Y

Cascaded operation capability

Applications

Y

COPSTMor microprocessor displays

Y

Industrial control indicator

Y

Digital clock, thermometer, counter, voltmeter

Y

Instrumentation readouts

Y

Remote displays

MM5452/MM5453 Liquid Crystal Display Drivers

February 1995

FIGURE 1

TL/F/6137– 1

COPSTMis a trademark of National Semiconductor Corp.

C

1995 National Semiconductor Corporation RRD-B30M105/Printed in U. S. A.

TL/F/6137

Absolute Maximum Ratings

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.

Voltage at Any Pin V

SS

Operating Temperature 0§Ctoa70§C

to V

a

10V

SS

Storage Temperature

Power Dissipation 300 mW ata70§C

Junction Temperature

b

65§Ctoa150§C

350 mW at

a

a

25§C

150§C

Lead Temperature (Soldering, 10 sec.) 300§C

Electrical Characteristics

TAwithin operating range, V

DD

e

3.0V to 10V, V

Parameter Conditions Min Typ Max Units

Power Supply 3 10 V

Power Supply Current Excluding Outputs

e

OSC

VSS,BPIN@32 Hz 40 mA

e

V

5V, Open Outputs, No Clock 10 mA

DD

Clock Frequency 500 kHz

Input Voltages

Logical ‘0’ Level V

Logical ‘1’ Level V

k

4.75

DD

t

V

4.75

DD

l

5.25 0.8 V

DD

s

V

5.25 2.0 V

DD

Output Current Levels

Segments

Sink V
Source V

Backplane

Sink V
Source V

DD

DD

DD

DD

e

3V, V

e

3V, V

e

3V, V

e

3V, V

Output Offset Voltage Segment Load 250 pF

Backplane Load 8750 pF (Note 1)

Clock Input Frequency, f

High Time, t

Low Time, t

h

l

(Notes 2 and 3) 500 kHz

C

Data Input

Set-Up Time, t
Hold Time, t

DS

DH

Data Enable Input

Set-Up Time, t

Note 1: This parameter is guaranteed (not 100% production tested) over operating temperature and supply voltage ranges. Not to be used in Q.A. testing.

Note 2: AC input waveform for test purpose: t

Note 3: Clock input rise and fall times must not exceed 300 ns.

DES

r

s

20 ns, t

e

0V, unless otherwise specified

SS

e

0.3V

OUT

e

b

V

OUT

e

OUT

e

OUT

s

20 ns, fe500 kHz, 50%g10% duty cycle.

f

0.3V 20 mA

DD

0.3V

b

V

0.3V 320 mA

DD

b

0.3 0.1 V

b

0.3 0.8 V

DD

DD

V

DD

DD

b

20 mA

b

320 mA

g

50 mV

950 ns

950 ns

300 ns
300 ns

100 ns

V

V
V

2

Connection Diagrams

Dual-In-Line Package

Dual-In-Line Package

Top View

TL/F/6137– 2

FIGURE 2a

Plastic Chip Carrier

TL/F/6137– 11

Top View

Order Number MM5452N, MM5453N,

MM5452V or MM5453V

See NS Package Number N40A or V44A

Functional Description

The MM5452 is specifically designed to operate 4 (/2-digit 7­segment 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. Since the MM5452 does not contain a character
generator, the formatting of the segment information must
be done prior to inputting the data to the MM5452. Using a
format of a leading ‘‘1’’ followed by the 32 data bits allows
data transfer without an additional load signal. The 32 data

Top View

FIGURE 2b

Plastic Chip Carrier

Top View

bits are latched after the 36th clock is complete, thus pro­viding non-multiplexed, direct drive to the display. Outputs
change only if the serial data bits differ from the previous
time.

A block diagram is shown in
DATA ENABLE
DATA ENABLE
be brought out. This is the MM5453 device.

is used instead of the 33rd output. If the

signal is not required, the 33rd output can

Figure 1.

TL/F/6137– 3

TL/F/6137– 12

For the MM5452 a

3

Functional Description (Continued)

Figure 4

shows the input data format. A start bit of logical
‘‘1’’ precedes the 32 bits of data. At the 36th clock a LOAD
signal is generated synchronously with the high state of the
clock, which loads the 32 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 configura­tion. There is no clear for the master portion of the first shift
register, thus allowing continuous operation.

If the clock is not continuous, there must be a complete set
of 36 clocks otherwise the shift registers will not clear.

Figure 2a

bit following the start bit and it will appear on pin 18.

Figure 3

and DATA ENABLE

shows the pin-out of the MM5452. Bit 1 is the first

shows the timing relationships between data, clock

.

FIGURE 3

FIGURE 4. Input Data Format

TL/F/6137– 4

TL/F/6137– 5

4

Functional Description (Continued)

Figure 5

data maps to the output pins and the display. The MM5452
and MM5453 do not have format restrictions, as all outputs

shows a typical application. Note how the input

are controllable. This application assumes a specific display
pinout. Different display/driver connection patterns will, of
course, yield a different input data format.

Consult LCD manufacturer’s data sheet for specific pinouts.

FIGURE 5. Typical 4(/2-Digit Display Application

TL/F/6137– 6

5

Functional Description (Continued)

*The minimum recommended value for R for the oscillator input is 9 kX . An RC time constant of approximately

b

4

c

4.91

10

should produce a backplane frequency between 30 Hz and 150 Hz.

FIGURE 6. Parallel Backplane Outputs

FIGURE 7. External Backplane Clock

Figure 8

shows a four wire remote display that takes advan­tage 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 7,

a flip-flop is used to assure
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.

TL/F/6137– 7

Figure 9

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
converter or resistor array. The result of this comparison is
clocked into the MM5452, MM5453. The next clock pulse
increments the staircase and clocks the new data in.

With a buffer amplifier, the same staircase waveform can be
used for many displays. The digital-to-analog converter
need not be linear; logarithmic or other non-linear functions
can be displayed by using weighted resistors or special
DACs. This system can be used for status indicators, spec­trum analyzers, audio level and power meters, tuning indica­tors, and other applications.

6

TL/F/6137– 8

Functional Description (Continued)

FIGURE 8. Four Wire Remote Display

Data is high until staircaselinput

FIGURE 9. Analog Display

Physical Dimensions inches (millimeters)

TL/F/6137– 9

TL/F/6137– 10

Molded Dual-In-Line Package (N)

Order Number MM5452N or MM5453N

NS Package Number N40A

7

Physical Dimensions inches (millimeters) (Continued)

Plastic Chip Carrier (V)

Order Number MM5452V or MM5453V

NS Package Number V44A

MM5452/MM5453 Liquid Crystal Display Drivers

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SEMICONDUCTOR CORPORATION. As used herein:

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failure to perform, when properly used in accordance support device or system, or to affect its safety or
with instructions for use provided in the labeling, can effectiveness.
be reasonably expected to result in a significant injury
to the user.

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