M5482 LED DISPLAY DRIVER FEATURES SUMMARY ■ 2 DIGIT LED DRIVER (15 segments) ■ CURRENT GENERATOR OUTPUTS (no resistor required) ■ CONTINUOUS BRIGHTNESS CONTROL ■ SERIAL DATA INPUT ■ WIDE SUPPLY VOLTAGE OPERATION ■ TTL COMPATIBILITY play brightness by setting a reference current through a variable resistor connected either to VDD or to a separate supply of 13.2V maximum. Figure 1. Package APPLICATION EXAMPLES ■ MICROPROCESSOR DISPLAYS ■ INDUSTRIAL CONTROL INDICATOR ■ RELAY DRIVER ■ INSTRUMENTATION READOUTS PDIP20 (Plastic package) DESCRIPTION The M5482 is a monolithic MOS integrated circuit produced with an N-channel silicon gate technology. It utilizes the M5451 die packaged in a 20-pin plastic package copper frame, making it ideal for a 2-digit display. A single pin controls the LED disFigure 2. Pin Connections OUTPUT BIT 8 1 20 OUTPUT BIT 9 OUTPUT BIT 7 2 19 OUTPUT BIT 10 OUTPUT BIT 6 3 18 OUTPUT BIT 11 OUTPUT BIT 5 4 17 OUTPUT BIT 12 OUTPUT BIT 4 5 16 OUTPUT BIT 13 OUTPUT BIT 3 6 15 V SS OUTPUT BIT 2 7 14 OUTPUT BIT 14 OUTPUT BIT 1 8 13 OUTPUT BIT 15 BRIGHTNESS CONTROL 9 12 DATA IN 10 11 CLOCK V DD REV. 2 June 2004 1/10 M5482 Figure 3. Block Diagram V DD BRITGHTNESS CONTROL OUTPUT BIT 15 OUTPUT BIT 1 13 8 10 9 35 OUTPUT BUFERS 1nF LOAD 35 LATCHES SERIAL DATA 12 CLOCK 11 35 BIT SHIFT REGISTER RESET 15 Table 1. Absolute Maximum Ratings Symbol VDD VI VO(off) IO PTOT Tj Parameter Value Unit Supply Voltage – 0.3 to 15 V Input Voltage – 0.3 to 15 V Off State Output Voltage 15 V Output Sink Current 40 mA Total Package Power Dissipation at 25°C 1.5 W Total Package Power Dissipation at 85°C 800 mW Junction Temperature 150 °C – 25 to 85 °C – 65 to 150 °C TOPER Operating Temperature Range TSTG Storage Temperature Range Note: Stresses in excess of those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions in excess of those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. 2/10 M5482 Table 2. Static Electrical Characteristics (Tamb within operating range, VDD = 4.75V to 13.2V, VSS = 0V, unless otherwise specified) Symbol Parameter Test Conditions VDD Supply Voltage IDD Supply Current VDD = 13.2V VI Input Voltage Logical "0" Level ± 10µA Input Bias Logical "1" Level 4.75 ≤ VDD ≤ 5.25 VDD > 5.25 IB Brightness Input Current (note 2) VB Brightness Input Voltage (pin 9) VO(off) IO Input Current = 750µA, Tamb = 25°C Typ. Unit 13.2 V 7 mA - 0.3 0.8 V 2.2 VDD V VDD - 2 VDD V 0 0.75 3 4.3 mA V 13.2 V 10 µA 10 µA mA Out. Sink Current (note 3) fclock IO Max. 4.75 Off State Out. Voltage Segment OFF VO = 3V Segment ON VO = 1V (note 4) Brightness In. = 0µA Note: 1. 2. 3. 4. Min. 0 Brightness In. = 100µA 2 2,7 4 Brightness In. = 750µA 12 15 25 mA 0.5 MHz ± 20 % Input Clock Frequency 0 Output Matching (note 1) Output matching is calculated as the percent variation from IMAX + IMIN/2. With a fixed resistor on the brightness input some variation in brightness will occur from one device to another. Absolute maximum for each output should be limited to 40mA. The VO voltage should be regulated by the user. FUNCTIONAL DESCRIPTION The M5482 uses the M5451 die which is packaged to operate 2-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 2 signals, serial data and clock. Using a format of a leading "1" followed by the 35 data bits allows data transfer without an additional load signal. The 35 data bits are latched after the 36th bit is complete, thus providing non-multiplexed, direct drive to the display. 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 1nF capacitor should be connected to brightness control, Pin 9, to prevent possible oscillations. A block diagram is shown in Figure 3. The output current is typically 20 times greater than the current into Pin 9, which is set by an external variable resistor. There is an internal limiting resistor of 400Ω nominal value. Figure 4 shows the input data format. A start bit of logical "1" precedes the 35 bits of data. At the 36th clock a LOAD signal is generated synchronously with the high state of the clock, which loads the 35 bits of the shift registers into the latches. 3/10 M5482 Figure 4. Input Data Format 1 36 CLOCK START BIT 1 BIT 34 BIT 35 DATA LOAD (INTERNAL) RESET (INTERNAL) The following equation can be used for calculations. Tj … [(VOUT)(ILED)(no.of segments) + VDD . 7 mA] (80 °C/W) + Tamb where: Tj ≡ junction temperature (150 °C max) VOUT = the voltage at the LED driver outputs ILED = the LED current 80 °C/W = thermal coefficient of the package Tamb = ambient temperature 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 configurations. There is no clear for the master portion of the first shift register, thus allowing continuous operation. There must be a complete set of 36 clocks or the shift registers will not clear. When power is first applied to the chip an internal power ON reset signal is generated which resets all registers and all latches. The START bit and the first clock return the chip to its normal operation. Figure 5 shows the timing relationships between Data and Clock. A maximum clock frequency of 0.5 MHz is assumed. Table 3 shows the Output Data Format for the M5482. Because it uses only 15 of the possible 35 outputs, 20 of the bits are "Don’t Cares". 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. Figure 5. CLOCK DATA 300ns (min.) Table 3. Serial Data Bus / Outputs Correspondence 5451 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 START 5482 15 X X X X 14 13 X X X X 12 11 10 9 X X X START 5451 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 START 5482 X 8 7 6 5 X X X X 4 3 2 1 X X X X START 4/10 M5482 TYPICAL APPLICATION Figure 6. BASIC electronically tuned TV system LED DISPLAY 15 SEGMENTS M5482 DISPLAY DRIVER KEYBOARD PROCESSOR POWER DISSIPATION OF THE IC The power dissipation of the IC can be limited using different configurations. Figure 7. a) +V C PLL SYNTHESIZER In this application R must be chosen taking into account the worst operating conditions. R is determined by the maximum number of segments activated. V –V –V C DMAX OMIN R = ---------------------------------------------------------------N L MAX D R ID VD V OUT The worst case condition for the device is when roughly half of the maximum number of segments are activated. It must be checked that the total power dissipation does not exceed the absolute maximum ratings of the device. In critical cases more resistors can be used in conjunction with groups of segments.In this case the current variation in the single resistor is reduced and Ptot limited. 5/10 M5482 Figure 8. b) Figure 9. +V C c) +VC V OUT +V D In this configuration the drop on the serial connected diodes is quite stable if the diodes are properly chosen. The total power dissipation of the IC depends only, in first approximation, on the number of segments activated. 6/10 In this configuration VOUT+VD is constant. the total power dissipation of the IC depends only on the number of segments activated. M5482 PART NUMBERING Table 4. Order Codes Part Number Package Temperature Range M5482B7 PDIP20 -25 to 85 °C 7/10 M5482 PACKAGE MECHANICAL Table 5. PDIP20 - Mechanical Data millimeters inches Symbol Min a1 0.254 B 1.39 Typ Max Min Typ Max 0.010 1.65 0.055 0.065 b 0.45 0.018 b1 0.25 0.010 D 25.4 1.000 E 8.5 0.335 e 2.54 0.100 e3 22.86 0.900 F 7.1 0.280 i 3.93 0.155 L 3.3 0.130 Z 1.34 0.053 I b1 L a1 Figure 10. PDIP20 - Package Dimensions B b Z e3 e E Z D 11 1 10 F 20 Note: Drawing is not to scale 8/10 M5482 REVISION HISTORY Table 6. Revision History Date Revision Description of Changes May-1993 1 First Issue 9-June-2004 2 Stylesheet update. No content change. 9/10 M5482 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners © 2004 STMicroelectronics - All rights reserved STMicroelectronics GROUP OF COMPANIES Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States www.st.com 10/10