MM5452/MM5453 Liquid Crystal Display Drivers Y General Description Y 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. Y Y Y Y Applications Y Y Y Y Features Y Y DATA ENABLE (MM5452) Wide power supply operation TTL compatibility 32 or 33 outputs Alphanumeric and bar graph capability Cascaded operation capability Y COPSTM or microprocessor displays Industrial control indicator Digital clock, thermometer, counter, voltmeter Instrumentation readouts Remote displays Serial data input No load signal required Block Diagram TL/F/6137 – 1 FIGURE 1 COPSTM is a trademark of National Semiconductor Corp. C1995 National Semiconductor Corporation TL/F/6137 RRD-B30M105/Printed in U. S. A. MM5452/MM5453 Liquid Crystal Display Drivers February 1995 Absolute Maximum Ratings Storage Temperature If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Voltage at Any Pin Operating Temperature Power Dissipation VSS to VSS a 10V 0§ C to a 70§ C Junction Temperature Lead Temperature (Soldering, 10 sec.) b 65§ C to a 150§ C 300 mW at a 70§ C 350 mW at a 25§ C a 150§ C 300§ C Electrical Characteristics TA within operating range, VDD e 3.0V to 10V, VSS e 0V, unless otherwise specified Parameter Conditions Min Power Supply Power Supply Current 3 Excluding Outputs OSC e VSS, BP IN @ 32 Hz VDD e 5V, Open Outputs, No Clock Clock Frequency Input Voltages Logical ‘0’ Level Logical ‘1’ Level Output Current Levels Segments Sink Source Backplane Sink Source VDD k 4.75 VDD t 4.75 VDD l 5.25 VDD s 5.25 b 0.3 b 0.3 0.8 VDD 2.0 VDD e 3V, VOUT e 0.3V VDD e 3V, VOUT e VDD b 0.3V 20 VDD e 3V, VOUT e 0.3V VDD e 3V, VOUT e VDD b 0.3V 320 Output Offset Voltage Segment Load 250 pF Backplane Load 8750 pF (Note 1) Clock Input Frequency, fC (Notes 2 and 3) Typ Max Units 10 V 40 10 mA mA 500 kHz 0.1 VDD 0.8 VDD VDD V V V V b 20 mA mA b 320 mA mA g 50 mV 500 kHz High Time, th 950 ns Low Time, tl 950 ns Data Input Set-Up Time, tDS Hold Time, tDH 300 300 ns ns 100 ns Data Enable Input Set-Up Time, tDES 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: tr s 20 ns, tf s 20 ns, f e 500 kHz, 50% g 10% duty cycle. Note 3: Clock input rise and fall times must not exceed 300 ns. 2 Connection Diagrams Dual-In-Line Package Dual-In-Line Package TL/F/6137 – 2 TL/F/6137 – 3 Top View FIGURE 2a Top View FIGURE 2b Plastic Chip Carrier Plastic Chip Carrier TL/F/6137 – 11 TL/F/6137 – 12 Top View 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 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 Figure 1. For the MM5452 a DATA ENABLE is used instead of the 33rd output. If the DATA ENABLE signal is not required, the 33rd output can be brought out. This is the MM5453 device. 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 shows the pin-out of the MM5452. Bit 1 is the first bit following the start bit and it will appear on pin 18. Figure 3 shows the timing relationships between data, clock and DATA ENABLE. TL/F/6137 – 4 FIGURE 3 TL/F/6137 – 5 FIGURE 4. Input Data Format 4 Functional Description (Continued) Figure 5 shows a typical application. Note how the input data maps to the output pins and the display. The MM5452 and MM5453 do not have format restrictions, as all outputs are controllable. This application assumes a specific display pinout. Different display/driver connection patterns will, of course, yield a different input data format. TL/F/6137 – 6 Consult LCD manufacturer’s data sheet for specific pinouts. FIGURE 5. Typical 4(/2-Digit Display Application 5 Functional Description (Continued) TL/F/6137 – 7 *The minimum recommended value for R for the oscillator input is 9 kX. An RC time constant of approximately 4.91 c 10b4 should produce a backplane frequency between 30 Hz and 150 Hz. FIGURE 6. Parallel Backplane Outputs TL/F/6137 – 8 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. 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. 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. 6 Functional Description (Continued) TL/F/6137 – 9 FIGURE 8. Four Wire Remote Display TL/F/6137 – 10 Data is high until staircase l input FIGURE 9. Analog Display Physical Dimensions inches (millimeters) Molded Dual-In-Line Package (N) Order Number MM5452N or MM5453N NS Package Number N40A 7 MM5452/MM5453 Liquid Crystal Display Drivers Physical Dimensions inches (millimeters) (Continued) Plastic Chip Carrier (V) Order Number MM5452V or MM5453V NS Package Number V44A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Europe Fax: (a49) 0-180-530 85 86 Email: cnjwge @ tevm2.nsc.com Deutsch Tel: (a49) 0-180-530 85 85 English Tel: (a49) 0-180-532 78 32 Fran3ais Tel: (a49) 0-180-532 93 58 Italiano Tel: (a49) 0-180-534 16 80 National Semiconductor Hong Kong Ltd. 13th Floor, Straight Block, Ocean Centre, 5 Canton Rd. Tsimshatsui, Kowloon Hong Kong Tel: (852) 2737-1600 Fax: (852) 2736-9960 National Semiconductor Japan Ltd. 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