MM5486 LED Display Driver Y General Description Y The MM5486 is a monolithic MOS integrated circuit utilizing N-channel metal-gate low-threshold, enhancement mode and ion-implanted depletion mode devices. It is available in a 40-pin molded dual-in-line package. The MM5486 is designed to drive common anode-separate cathode LED displays. A single pin controls the LED display brightness by setting a reference current through a variable resistor connected to VDD. Y Y Y Y Applications Y Y Features Y Y Y Continuous brightness control Serial data input/outut External load input Cascaded operation capability Wide power supply operation TTL compatibility 33 outputs, 15 mA sink capability Alphanumeric capability Y Y COPSTM or microprocessor displays Industrial control indicator Relay driver Digital clock, thermometer, counter, voltmeter Instrumentation readouts Block and Connection Diagrams Dual-In-Line Package TL/F/6142 – 1 FIGURE 1 TL/F/6142 – 2 Top View Order Number MM5486N See NS Package Number N40A FIGURE 2 TL/F/6142 – 13 Order Number MM5486V See NS Package Number V44A COPSTM is a trademark of National Semiconductor Corporation. C1995 National Semiconductor Corporation TL/F/6142 RRD-B30M105/Printed in U. S. A. MM5486 LED Display Driver February 1995 Absolute Maximum Ratings Power Dissipation at 25§ C Molded DIP Package, Board Mount Molded DIP Package, Socket Mount If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Voltage at Any Pin VSS to VSS a 12V Operating Temperature Storage Temperature 2.5W* 2.3W** Junction Temperature b 25§ C to a 85§ C a 150§ C Lead Temperature (Soldering, 10 seconds) 300§ C *Molded DIP Package, Board Mount, iJA e 49§ C/W, Derate 20.4 mW/§ C above 25§ C. b 65§ C to a 150§ C **Molded DIP Package, Socket Mount, iJA e 54§ C/W, Derate 18.5 mW/§ C above 25§ C. Electrical Characteristics TA within operating range, VDD e 4.75V to 11.0V, VSS e 0V, unless otherwise specified Symbol Parameter Conditions VDD Power Supply IDD Power Supply Current Excluding Output Loads VIL VIH Input Voltages Logic ‘‘0’’ Level Logic ‘‘1’’ Level g 10 mA Input Bias 4.75 s VDD s 5.25 VDD l 5.25 IBR Brightness Input (Note 2) IOH IOL Output Sink Current (Note 3) Segment OFF Segment ON IO Maximum Segment Current VIBR Brightness Input Voltage (Pin 19) OM Output Matching (Note 1) VOL VOH Data Output Logical ‘‘0’’ Level Logical ‘‘1’’ Level fC th tl Clock Input Frequency High Time Low Time tDS tDH Data Input Set-Up Time Hold Time Min Typ 4.75 b 0.3 2.2 Units 11 V 7 mA 0.8 VDD V V VDDb2 VDD V 0 0.75 mA 10 mA 10 4 25 mA mA mA VOUT e 3.0V VOUT e 1V (Note 4) Brightness Input e 0 mA Brightness Input e 100 mA Brightness Input e 750 mA 0 2.0 15 Input Current e 750 mA 3.0 IOUT e 0.5 mA IOUT e 100 mA Max 2.7 40 mA 4.3 V g 20 % 0.4 VDD V V 500 950 950 kHz ns ns 300 300 ns ns VSS 2.4 (Notes 5 and 6) Note 1: Output matching is calculated as the percent variation (IMAX a IMIN)/2. Note 2: With a fixed resistor on the brightness input pin, some variation in brightness will occur from one device to another. Maximum brightness input current can be 2 mA as long as Note 3 and junction temperature equation are complied with. Note 3: Absolute maximum for each output should be limited to 40 mA. Note 4: The VOUT voltage should be regulated by the user. See Figures 6 and 7 for allowable VOUT vs IOUT operation. Note 5: AC input waveform specification for test purpose: tr s 20 ns, tf s 20 ns, f e 500 kHz, 50% g 10% duty cycle. Note 6: Clock input rise and fall times must not exceed 300 ns. 2 Functional Description When the chip first powers ON, an internal power ON reset signal is generated which resets all registers and latches. The leading clock returns the chip to its normal operation. The MM5486 is specifically designed to operate four-digit alphanumeric 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 3 signals, serial data, clock, and load. The data bits are latched by a positive-level load signal, thus providing non-multiplexed, direct drive to the display. When load is high, the data in the shift registers is displayed on the output drivers. Outputs change only if the serial data bits differ from the previous time. Display brightness is determined by control of the output current for LED displays. A 0.001 mF capacitor should be connected to brightness control, pin 19, to prevent possible oscillations. The output current is typically 20 times greater than the current into pin 19, which is set by an external variable resistor. There is an internal limiting resistor of 400X nominal value. A block diagram is shown in Figure 1 . Figure 3 shows the timing relationship between data, clock and data enable. A maximum clock frequency of 0.5 MHz is assumed. For applications where a lesser number of outputs are used, it is possible to either increase the current per output, or operate the part at higher than 1V VOUT. The following equation can be used for calculations: TJ e (VOUT) (ILED) (No. of segments) (iJA) a TA where: TJ e junction temperature, 150§ C max. VOUT e the voltage at the LED driver outputs ILED e the LED current iJA e thermal coefficient of the package TA e ambient temperature iJA (Socket Mount) e 54§ C/W iJA (Board Mount) e 49§ C/W The above equation was used to plot Figure 6, Figure 7, and Figure 8 . Figure 4 shows the input data format. Bit ‘‘1’’ is the first bit into the data input pin and it will appear on pin 17. A logical ‘‘1’’ at the input will turn on the appropriate LED. The load signal latches the 33 bits of the shift register into the latches. The data out pin allows for cascading the shift registers for more than 33 output drivers. TL/F/6142 – 3 FIGURE 3 TL/F/6142 – 4 *This leading clock is necessary only after power ON. FIGURE 4. Input Data Format TL/F/6142 – 5 FIGURE 5 3 Typical Applications TL/F/6142 – 8 TL/F/6142 – 7 TL/F/6142–6 FIGURE 7 FIGURE 6 FIGURE 8 TL/F/6142 – 9 I19 e DV 1k FIGURE 9. Constant Current Brightness Control TL/F/6142 – 10 FIGURE 10. Brightness Control Varying the Duty Cycle 4 Typical Applications (Continued) Basic Electronically Tuned Radio System TL/F/6142 – 11 Duplexing 8 Digits with One MM5486 TL/F/6142 – 12 *This driver has 7 segments only. 5 6 Physical Dimensions inches (millimeters) Molded Dual-In-Line Package (N) Order Number MM5486 NS Package Number N40A 7 MM5486 LED Display Driver Physical Dimensions inches (millimeters) (Continued) 44-Lead Plastic Chip Carrier (V) Order Number MM5486V 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. 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