SUA ALSVI 8 Digit LED Display Driver General Description The Maxim ICM7218 display driver interfaces micro- processors to an 8 digit, 7 segment, numeric LED display. Included on chip are two types of 7 segment decoders, multiplex scan circuitry, segment and digit drivers, and an 8 ~< 8 static memory. The ICM7218A and 1CM7218B accept data in a serial format and drive common anode (ICM7218A) or common cathode (ICM7218B) displays. The ICM7218C and ICM7218D accept data in a parallel format and drive common anode (ICM7218C) or common cathode (ICM7218D) displays. All four versions can display the data in either hexadecimal or code B format. The 1CM7218A and ICM7218B also feature a No Decode mode where each individual segment can be inde- pendently controlled. This is particularly useful in driving bar graphs. The Maxim ICM7218 is an alternative for both the Intersil ICM7218 and ICM7228. When ordering, specify 1{CM7218 for both devices. Applications Instrumentation Test Equipment Hand Held Instruments Bargraph Displays Panel Meters Typical Operating Circuit Features @ Improved 2nd Source! See 3rd page of this data sheet for our Maxim Advantage @ Fast Access Time: 200ns Write Pulse Width @ Microprocessor Compatible @ Hexadecimal and Code B Decoders @ Individual Segment Control with No Decode Feature @ Digit and Segment Drivers On-Chip @ Common Anode and Common Cathode LED versions available @ Low Power CMOS Ordering information ee ee EV ED) Ct) CP) a) EN) Eb ed FLD ED| 7, TET. ET, ED. ET. Lo} J J J J J +OV *oV MAXIM 8048 ICM72184 1CM7218B | 8 picits @ SEGMENTS t 8 Digit Microprocessor Display PART TEMP. RANGE PACKAGE* ICM7218A IPI -20C to +85C 28 Lead Plastic DIP ICM7218AlJ| -20C to +85C 28 Lead CERDIP ICM7218BIPI -20C to +85C 28 Lead Plastic DIP ICM7218BlJl -20C to +85C 28 Lead CERDIP ICM7218CIPI -20C to +85C 28 Lead Plastic DIP ICM7218ClJI -20C to +85C 28 Lead CERDIP ICM7218DIPI -20C to +85C 28 Lead Plastic DIP (CM7218DIJI -20C to +85C 28 Lead CERDIP (Ordering Information Continued on Last Page.) Pin Configuration Top View Se6C [1 Je 26) GROUND sege [2] 27] SEGA SEG B [3 26) SEG G DP te 2] SEG 0 1D6 {HEXA/CODE 8) (5 | 24] SEG F 105 (DECODE) (6 | 23] OIGIT 3 107 (OATA COMING) [7] AAAXIAN [2] oIGiT 6 write (8) /CM7218A_ [21] nigit7 mone [3 | 20] DIGIT 4 104 (SHUTDOWN) [10] Lite iol G0 [18] oigtT 8 loo G2] [17] oigit 5 In [734 16] DIGIT 2 103 [14] [15] DIGIT | MA AKIM For free samples & the latest literature: htip:/;www.maxim-ic.com, or phone 1-800-998-8800 Maxim Integrated Products 82CLWII/8ILCLWNII1CM7218/1ICM7228 8 Digit LED Display Driver ABSOLUTE MAXIMUM RATINGS Supply Voltage ...... ec ccc ccc cence cece cence eee eeees 6V Power Dissipation (28 Pin Plastic Digit Output Current .............2...000 cece eee 500mA with Copper Leadframe) .................0. 1.0W (Note 2) Segment Output Current .................00 00 100mA Power Dissipation (28 Pin Quad Pack) 0.8W (Note 2) Input Voltage (any terminal) ..... V* + 0.3V to GND -0.3V Operating Temperature Range .......... -20C to +85C (Note 1) Storage Temperature Range ............. -65C to 160C Power Dissipation (28 Pin CERDIP) ...... 1.0W (Note 2) Lead Temperature (Soldering 10 sec) ............. 300C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum ratings conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V' = 5v + 10%, T, = 25C) PARAMETER SYMBOL CONDITIONS MIN TYP MAX | UNITS Operating Voltage ve Power Down Mode 3 e Vv Quiescent Supply Current lg Shutdown (Note 3) 6 10 300 HA . Decoder On, Outputs Open Ckt 250 950 Operating Supply Current lop | No Decode, Outputs Open Ckt 200 450 | 4A a Common Anode Voy = V" - 2.0V -170 Digit Drive Current loig Common Cathode Voyy = V+ 1V 50 mA Digit Leakage Current louk 100 LA . Common Anode Voy = V+ 1.5V 20 25 Peak Segment Drive Current Iseg Common Cathode Voyy = V" - 2.0V 40 mA Segment Leakage Current Isui 50 uA Display Scan Rate faux Per Digit 250 Hz Three Level Input Logical 1 Input Voltage Vind Hexadecimal |CM7218C, D (Pin 9) 4.0 Vv Floating Input Vine Code B ICM7218C, D (Pin 9) 2.0 3.0 Logical 0 Input Voltage Vint Shutdown ICM7218C, D (Pin 9) 1.75 Three Level Input Impedance Zin Note 3 100 kQ Logical 1 Input Voltage Vin 3.5 Vv Logical 0 Input Voltage Vit 0.8 Write Pulse Width (Negative) tw 550 400 Write Pulse Width (Positive) ty | 72184.8 550 400 ns Write Pulse Width (Negative) tw 400 250 Write Pulse Width (Positive) ty, 7218C, D 400 250 ns Mode Hold Time tian 7218A, B 150 ns Mode Pulse Width tm 7218A, B 500 ns Data Set Up Time tgs 500 ns Data Hold Time ton 25 ns Digit Address Set Up Time taas ICM7218C, D 500 ns Digit Address Hold Time tan ICM7218C, D 100 Data Input Impedance Zin 5-10pF Gate Capacitance 10 Ohms Note 1: Due to the SCR structure inherent in the CMOS process used to fabricate these devices, connecting any terminal to a voltage greater than V* or less than GROUND may cause destructive device latchup. For this reason it is recommended that no inputs from sources operating on a different power supply be applied to the device before its own supply is established, and when using multiple supply systems the supply to the ICM7218 should be turned on first. Note 2: These limits refer to the package and will not be obtained during normal operation. Derate above 50C by 25mW per C. Note 3: In the |CM7218C and D (random access versions) the Hexa/Code B/Shutdown Input (Pin 9) has internal biasing resistors to hold it at V/2 when Pin 9 is open circuited. These resistors consume power and result in a Quiescent Supply Current (Ig) of typically 50uA. The ICM7218A and B devices do not have these biasing resistors and thus are not subject to this condition. The electrical characteristics above are a reproduction of a portion of intersils copyrighted (1983, 1984) data book. This information does not constitute any representation by Maxim that Intersils products will perform in accordance with these specifications. The Electrical Characteristics Table along with the descriptive excepts from manufacturer's data sheet have been included in this data sheet solely for comparative purposes. 2 MAAISVIMAAAL/VI ADVANTAGE 8 Digit LED Display Driver @ 200ns Write Pulse Width @ Guaranteed Interdigit Blanking Time @ Zero Hold Time - Mode, Data and Address @ Increased LED Display Drive Current @ Single Digit Update Mode ICM7218A, B @ Improved ESD Protection (Note 4) @ Maxim Quality and Reliability ABSOLUTE MAXIMUM RATINGS: This device conforms to the Absolute Maximum Ratings on adjacent page. ELECTRICAL CHARACTERISTICS (V = 5V + 10%, T, = 25C) PARAMETER SYMBOL CONDITIONS MIN TYP MAX | UNITS Supply Voltage vi | -20C < T, < +85C pera ion 8 V ICM7218A, B 5 300 Shutdown Supply Current lo ICM7218C, D (3 level input open) 25 300 | 4A Decoding all 8's, display open 200 450 uA No Decode, display outputs open 200 450 uA Operating Supply Current lop Display blank, driving display 200 450 uA Decoding all 8s and D.P.s, driving display 240 mA ia Dri Common Anode Voy, = V" - 2.0V -200 -300 mA Digit Drive Current loc Common Cathode Voyr = 1.0V 50 70 mA Shutdown, V* = 5V Digit Leakage Current lok Common Anode, Voyr = OV -10 -100 uA Common Cathode, Voy7 = 5V 10 100 uA . Common Anode Voyz = 1.5V 20 30 Peak Segment Drive Current Iseg Common Cathode Voy; = V" - 2.0V 10 20 mA Shutdown, V* = 5V Segment Leakage Current Isuk Common Anode, Voy; = 5V -1 -50 LA Common Cathode, Voy = OV 1 50 uA All inputs except pin 9 of ICM7218C, D V' = SV, -20C < T, < +85C Input Leakage Current ! P a i Vin = OV -0.01 -1 HA Vin = 5V 0.01 1 uA Display Scan Rate faux Vv = 5V 75 250 Hz Interdigit Blanking Time tgp Vv = 5V 2 10 US Pin 9, ICM7218 C, D only, V = 5V Vinny Input high voltage 42 V Three Level Input Vine | Floating input 20 3.0 V Vin Input low voltage 0.8 Vv Three Level Input Impedance Zin Pin 9, ICM7218C, D only 50 100 kQ Input High Voltage Vv All inputs except pin 9 of ICM7218C, D 2.0 Vv tH Input Low Voltage Vit -20C <= Ty = +85C 0.8 V Write Pulse Width (Low) ty 200 100 ns Write Pulse Width (High) twh 1.0 us Input Setup Time tids (Note eo except pin 9 of ICM7218C, D 250 150 ns Input Hold Time tran (Notes) except pin 9 of ICM7218C, D 0 -20 ns Note 4: All pins are designed to withstand electrostatic discharge (ESD) levels in excess of 2000V (Mil Std 883B Method 3015.1 Test Circuit). Note 5: This specification replaces the original manufacturer's separate specifications for data, address, and mode inputs. MAALWI 3 8CCLWOI/8ICLNOIICM7218/1CM7228 8 Digit LED Display Driver Typical Operating Characteristics COMMON ANODE DIGIT DRIVER COMMON CATHODE SEGMENT DRIVER Inie VS. (* - Vout} Iseg VS. (* - Vout) 400 r 40 45V< Vi < 5.5V 4.5V < V" < 5.5V Tas +25 | Th = +25C A 300 30 = = S200 En 5 +25C g +75C 100 | | 10 / +85C i, +85C -20C y 20C 0 0 Vs 0 1 2 3 0 ] 2 3 Ve = Vour (VI V* - Vout () ICM7218A/B ICM7218C/D 10-107 03-107 MODE WRITE 100-103 INPUT 8 CONTROL HEXADECIMAL/ 107 nAO-DA2 DATA INPUTS, 1 anE B/ aaTA _ giGiT 4 SauTODWA wrut mare aonwess DECOUE t CONTROL SHUTDOWN HEXA/CODE B Logic THREE LEVEL y SHUTOOWN Ip INPUT LOGIC ? 1 } 1 WRITE 3 , ADORESS 3 DECODER bx WAITE ADDRESS 1 STATIC. 8 COUNTER 5x8 RAM STATIC RAM De By 8, 1 ! { r , AEAQ ADORESS MULTIPLEXER 4 8 READ ADDAESS, DIGIT : HEXADECIMAL/ 1 MULTIPLEXER CODE 8 HEXAQECIMAL/ DECODER A080 y DECODER MULTIPLEX 7 1 OSCILLATOR 7 MULTIPLEX g OECIMAL | OSCILLATOR POINT. >| vecone, 4 a 1L wnrenoieir NO-OECODE a BLANKING 8 SEGMENT DRIVERS uy 8 DIGIT rT DECIMAL 8 1] INTERDIGIT ORIVERS POINT : -T BLANKING 8 SEGMENT 8 DIGIT DRIVERS DRIVERS J 4 MAXIM8 Digit LED Display Driver Table 1. Input Definitions, ICM7218A and ICM7218B Note: Pin Configurations for the ICM7218A/B are shown on last page. INPUT PIN STATE FUNCTION WRITE 8 High Input Not Loaded Into Memory Low Input Loaded Into Memory MODE 9 High Loads Control Word on WR Low Loads Input Data on WR IDO-IDe2, 12, 11, 13 High Loads one DIGIT ADDRESS Low Loads zero ID3, BANK SELECT 14 High Select RAM Bank A (Hex or Code B Low Select RAM Bank B Data only) ID4, SHUTDOWN 10 High Normal Operation (MODE High) Low Shutdown ID5, DECODE/NO DECODE 6 High No Decode (MODE High) Low Decode ID6, HEX/CODE B 5 High Hexadecimal Decoding (MODE High) Low Code B Decoding ID7, DATA COMING 7 High Data Coming (control word) (MODE High) Low No Data Coming (control word) IDO-ID7, INPUT DATA 5-7, 10-14 High Loads one (Note 1) (MODE Low) Low Loads zero (Note 1) Note 1: A zero or low level on 1D7 turns ON the decimal point. In the NO DECODE mode, a one or high input turns ON the corresponding segment, except for the decimal point which is turned OFF by a high level on ID7. Detailed Description Input Data Formats The ICM7218A and ICM7218B have three possible data formats: Hexadecimal, Code B, and No Decode. Figure 7 lists the character sets for the decode modes. The data format of the 1CM7218A/B is selected by writing to bits ID4, D5, and ID6 of the control register (See Table 1, Input Definitions). Hexadecimal and Code B data is entered via IDO-iD3 while ID7 controls the decimal point. The No Decode mode of the ICM7218A and ICM7218B allows the direct segment-by-segment control of all 64 segments driven by the [CM7218. In the No Decode mode, the inputs directly control the outputs as follows: Data Input (D7 ID6 }IDS |1D4 |1D3 )1D2 |1D1 | IDO Controlled Decimal | A |B/]C|]E]G]F/D Segment Point An input high level turns on the respective segment, except for the decimal point, which is turned on by an input low level on ID7. The ICM7218C and ICM7218D have only Hexadecimal and Code B formats. The MODE input, pin 9, a three level input, selects the Hexadecimal format when driven high, the Code B format when floating or MIAALWVI driven to mid-supply, and the shutdown mode when driven low. Shutdown and Display Blanking When shutdown, the ICM7218 enters a low power standby mode which typically uses only 10uA of supply current. In this mode the 1CM7218 turns off the multiplex scan oscillator as well as the digit and segment drivers, however input data can still be en- tered when in the shutdown mode. Data is retained in memory even with the supply voltage as low as 2V. The ICM7218A/B is shutdown by writing a control word with Shutdown (ID4) low. The ICM7218C/D is put into shutdown mode by driving MODE low. The ICM7218 operating current with the display blanked is 200A. All versions of the ICM7218 can be blanked by writing Hex FF to all digits and selecting Code B format. The ICM7218A and ICM7218B can also be blanked by selecting No Decode mode and writing Hex 80 to all digits. Microprocessor Interface, ICM7218A and ICM7218B All Maxim ICM7218A/B inputs, including MODE, fea- ture a 250ns minimum data setup and Ons hold time. With a 200ns minimum write pulse, the 1CM7218 can directly interface to most microprocessor buses. Input logic levels are TTL and CMOS compatible. Figure 8 shows a typical method of driving the ICM7218A/B 82CLWNII/8ICZNOI1CM7218/1CM7228 8 Digit LED Display Driver Table 2. input Definitions, ICM7218C and ICM7218D Note: Pin Configurations for the ICM7218C/D are shown on last page. INPUT PIN STATE FUNCTION WRITE 8 High Input Not Loaded Into Memory Low Input Loaded Into Memory MODE 9 High Hexadecimal Decode {Note 1) Float Code B Decode Low Shutdown DAO-DA2, 5, 6, 10 High Loads ones DIGIT ADDRESS Low Loads zeros IDO-ID3, INPUT DATA 11-14 High Loads ones and ID7, D.P. 7 Low Loads zeros Note 1: Pin 9 of the ICM7218C and ICM7218D controls the selection of Hex, Code B, and Shutdown modes and is independent of the WRITE pulse. Note 2: A zero or low level on ID7 turns ON the decimal point segment. from a microprocessor bus. The MODE input is driven by AO and writing to an odd address updates the control register. The ICM7218A/B has three data entry modes: control word update without data update, 8 digit data update, and single digit data update. In all three modes the control register is first updated by pulsing the WRITE input while the MODE input is high, thereby latching data into the control register. The control register selects Shutdown, Decode/No Decode, and Hex/ Code B operation as shown in Table 1. A unique feature of the Maxim ICM7218A/B is that there are two banks of internal RAM in the Hexadecimal and Code B display formats. ID3 selects which bank of the internal RAM is displayed. The logic state of DATA COMING (1D7) is also latched during a control register update. If the latched value of DATA COMING (ID7) is high, the display is blanked and an 8 digit data update is initiated. The next 8 write pulses latch data into the 8 bytes of RAM onboard the ICM7218A/B, starting with digit 1 and ending with digit 8. After the eighth write pulse, the display unblanks and the new data is displayed. Addi- tional write pulses after the eighth pulse are ignored. All 8 digits are displayed in the data format (Hex/ Code B/No Decode) specified by the control word that preceded the 8 digit update. The control register can be rewritten without updating all 8 digits by writing to the ICM7218A/B with MODE high and DATA COMING low. No further action is necessary. Single Digit Update Mode The Maxim ICM7218A/B has a single digit update mode which allows one digit to be changed without updating the entire display. First the control register is updated with MODE high, DATA COMING (!D7) low, the desired data format on ID4 and ID6, and the address of the digit to be updated on data lines IDO-ID2 (See Table 3). A second write to the ICM7218, this time with MODE low, transfers the data from IDO- ID7 into the selected digits RAM location. The data format (Hex/Code B/No Decode) can be specified independently for each digit when in the single digit update mode. Compatibility with the Intersil ICM7218A and 1CM7218B The Maxim ICM7218A/B is upwardly compatible with the Intersil |CM7218A/B. The Maxim ICM7218A/B adds two functions: bank select and single digit update. IDO-ID3 are dont care when writing a control word to the Intersil 1CM7218A/B. When writing a control word to the Maxim I1CM7218A/B, IDO-ID2 select the address for a single digit update, while ID3 selects either bank A or bank B for Hex and Code B data. ID3 is a don't care for No Decode data. The bank select feature is upwardly compatible with the Intersil ICM7218A/B; software written for the Intersil ICM7218A/B will work with the Maxim 1CM7218A/B provided all control word updates have the same value for ID3, either high or low. The single digit update is upwardly compatible; it is an invalid operation with the Intersil ICM7218A/B and is unlikely to occur in software originally written for the Intersil |CM7218A/B. MAAIS/VI8 Digit LED Display Driver e| ton <_< {ms > INPUT CONTROL = MODE y INPUT DATA | t tw ! Ww WRITE . f <_ tis >| (CM7218A.B ONLY N INPUT DATA VALID ) Vi, Notes: 1. ty. = tgs = tyas 2 250ns - tin = tan = taan 2 Ons . ty 2 200ns . WRITE is rising edge sensitive, {dss > DIGIT ADDRESS & WN a VALID } ICM7218C,0 ONLY 77 | [me toon not level sensitive. Figure 3. Write Cycle Timing 100-107: Ui, MODE Wy Zi VA MODE = HIGH WY WRITE \ / (D7 = LOW SEE INPUT DEFINITIONS, TABLE 1 = TeV 81. wo XK XE ONGIT + BANK ADDRESS 8cSLWOI/8ILCZNOII Figure 4. Control Word Update Timing!CM7218A/B Figure 5. Single Digit Update TimingICM7218A/B CONTROL WORD UPDATE DIGIT 1 UPDATED DIGIT 2 UPDATED DIGIT 8 UPOATEO -/RBAA DISPLAY BLANKS WRITE -IX2>OOOM DOOM Notes: 1. Any write cycle with Mode high restarts data entry sequence at Control Word Update. 2. Display blanked by Control Word with Data Coming (1D7) high. 3. Display unblanks with rising edge of WRITE to Digit 8. Figure 6. 8 Digit Update TimingICM7218A/B MAALWI 71CM7218/1CM7228 8 Digit LED Display Driver ID3 | 1D2 ID1 | IDO | HEXADECIMAL | CODE B 0 0 0 0 Q @ 0 0 0 1 1 1 0 0 1 0 2 2 0 0 1 1 3 3 0 1 0 0 4 4 0 1 0 1 5 5 0 1 1 0 6 6 0 1 1 1 ? ? 1 0 0 0 8 8 1 0 0 1 3 9 1 0 1 0 a - 1 0 1 1 5 E 1 1 0 0 Cc H 1 1 0 1 d L 1 1 1 0 E Pp 1 1 1 1 F (Blank) Figure 7. Display Font IT: Segment Assignments Microprocessor Interface, ICM7218C and ICM7218D All Maxim ICM7218C and IMC7218D inputs are TTL and CMOS compatible with the exception of the three-level input, HEX/CODE B/SHUTDOWN (Pin 9). All other data and address inputs have identical 250ns setup and Ons hold times. The minimum write pulse width is 200ns, allowing direct interface to most microprocessor buses. Figure 9 shows a typical ICM7218C/D bus interface. The 8 digits of the ICM7218C/D are addressed as 8 contiguous bytes of RAM. The interface to the ICM7218C and ICM7218D is similar to that of a RAM. Select the digit to be updated with the address lines DAO-DA2, place the data to be written on IDO-ID3 and ID7, then pulse the WRITE input low. Since the ICM7218C/D does not have a control regis- ter, Hexadecimal or Code B font selection and shut- down mode are directly controlled through the three- level input at Pin 9. The ICM7218C/D does not have a No Decode mode. 8 DATA BUS WRITE} 2 Al415 Gl TALS138 8 00-07 YO-7 THTTTTY OR OTHER TO 2ND 1CM7218 1/0 ADDRESS BUS \Z 100-107 MAXIM 1CM7218A/B WRITE SEGMENTS ae ET Pt dt ty MODE DIGITS uy Figure 8. 1CM7218A/B uP Bus Interface 8 MAALYVI8 Digit LED Display Driver Applications Information Common Anode Display Interface, ICM7218A and ICM7218C The common anode digit and segment driver output schematics are shown in Figures 10 and 11. The common anode digit driver output impedance is approximately 4 ohms. This provides a nearly constant voltage to the display digits. The N-channel segment driver output impedance of 50 limits the segment current to approximately 30mA peak current per segment. Segment current limiting resistors are NOT required. Both the segment and digit outputs can directly drive the display. Each segments current is not significantly affected by whether other segments are on or off. This is because the segment driver output impedance is much higher than that of the digit driver. This feature is important in bar graph applications, where each bar graph element should be the same brightness, inde- pendent of the number of elements turned on. Common Cathode Display Interface, 1CM7218B and iCM7218D The common cathode digit and segment driver output schematics are shown in Figures 12 and 13. The N- channel digit drivers have an output impedance of approximately 150. The NPN segment drivers have an output impedance of approximately 75 ohms. The common cathode display driver output currents are only 1/4 the common anode display driver currents. Therefore, the ICM7218A and ICM7218C common anode display drivers are recommended for those Table 3. Digit Addressing DATA LINES Selected ID2 1D1 IDO Digit 0 0 0 Di 0 0 1 D2 0 1 0 D3 0 1 1 D4 1 0 0 DS 1 0 1 D6 1 1 0 07 1 1 1 D8 applications where high brightness is desired. The IGM7218B and ICM7218D common cathode display drivers are suitable for driving bubble-lensed mono- lithic 7 segment displays. They can also drive indi- vidual LED displays up to 0.3" height when high brightness is not required. Display Multiplexing Each digit of the ICM7218 is on for approximately 500us, with a multiplexing frequency of approximately 250Hz. The interdigit blanking time is 10us typical, 2us minimum. The Maxim ICM7218 turns off both the digit drivers and the segment drivers during the inter- digit blanking period. The digit multiplexing sequence is: D1, D7, D8, D6, D4, D3, D2, and D5. 8 4 ne 00-07 Gt 8 DATA BUS 74L8 138 _] [Cc G2A G2B aas\ To 2D 14 = } icmzzi8 j YO-Y7 FE ? op OTHER | 10 ABC A3-5 By annREss aus / 7 3VA0-2 100-107 MAAAXIM 1CM7218C/D ware segnewrst- Y l |] 8/8] alalal tty td pA0-3 DIGITS ua Figure 9. ICM7218C/D uP Bus Interface MAXAIsVI 8CCLWOI/SICZNOI1CM7218/1CM7228 8 Digit LED Display Driver ra DIGIT STROBE r| INTERDIGIT BLANKING SEGMENT DATA coMMON cOMMON ANODE ant INTERDIGIT a BLANKING OUTPUT - = SHUTDOWN SqUTOOWS$ $4 Figure 10. Common Anode Digit Driver Figure 11. Common Anode Segment Driver SEGMENT DATA DIGIT INTERDIGIT STROBE COMMON BLANKING CATHOOE ee DIGIT COMMON INTERDIGIT OUTPUT CATHODE BLANKING SEGMENT OUTPUT SHUTOOWN SHUTDOWN __________| Figure 12. Common Cathode Digit Driver Driving Larger Displays If very high display brightness is desired, the ICM7218 display driver outputs can be externally buffered. Figures 14 and 15 show how to drive either common anode or common cathode displays using the ICM7218B or ICM7218D. The Maxim ICM7218 has a guaranteed 2us interdigit blanking time. This elimi- nates the ghosting (faint display of the data from another digit) that would occur if the external buffer turnoff time were to overlap the beginning of the next digit period. Another method of doubling display currents is to connect two digit outputs together and load the same 10 Figure 13. Common Cathode Segment Driver data into both digits. This drives the display with the same peak current, but the average current doubles because each digit of the display is on for twice as long, i.e. for 1/4 duty cycle rather than 1/8. Three Level input, ICM7218C and ICM7218D. As shown in Table 1, pin 9 controls three functions: Hexadecimal display decoding, Code B display de- coding, and shutdown mode. In many applications pin 9 will be permanently wired to one state. When pin 9 cannot be permanently left in one state, use the circuits illustrated in Figure 16 to drive this three level input. MAALSVI8 Digit LED Display Driver +5V +oV +5V 1.4 AMP PEAK 2N6034 1002 SEGMENT iCM7218B/D OUTPUT 250 pit | OUTPUT (l00mA PEAK} 2N2219 +5V +5V 10020 SEGMENT QUTPUT JCM7218B/D 2N2219 140 (100mA PEAK] =2k0 DIGIT OUTPUT Figure 14. Driving Larger Common Anode Displays with External Transistors 740126 THREE-STATE BUFFER HIGH = HEX 4 PING LOW = SHUTDOWN HIGH = HEX OR SHUTDOWN LOW = CODE 8 HIGH = SHUTDOWN INai4g 4 PIN 9 LOW = CODE B HIGH = SHUTDOWN F 4069 PINS LOW = HEX OPEN DRAIN OR OPEN COLLECTOR OUTPUT HIGH = SHUTOOWN PIN 9 LOW = CODE B Figure 15. Driving Larger Common Cathode Displays with External Transistors Power Supply Bypassing Connect a minimum of 47uF in parallel with 01uF between V* and ground. These capacitors should be placed in close proximity to the ICM7218 to reduce the power supply ripple caused by the 200mA multi- plexed LED display drive current pulses. Package Information ose 1470. may i oe 11575) F (97340) - RAO eh eel bl i 0.600 - 0.620 0.54 + 0.008 (15.240 = 15.748) 5) (13.720 + 0.172) . | 0030 J, 0580 (0.762) Sererererrsrcreroeres aa7aoi 7] | MAX 0.040 + yp 0100 + 0010 syp Lm | (1.016) , (2540 + 0254) \a oF ; t ' ge tse 7) | 4 4 \ ~ 005020015 | Qlso+0005 | #0025, | ol be 770 038) (38100127) 0125 0.020 9.625 pong | (3175) 10.508) 055, | BBPe ae TP _ 0018+ 0.003 MIN "15.875 "py 3i! 0.009 - 0.015 (0.457 + 0.076) (0.229 - 0.318) TYP 28 Lead Plastic (Pl) with Copper Leadframe Hi, 60C. W Figure 16. Drive Circuits for 1CM7218C/D MODE Input SUAAI/VI 1 8ECLWNOI/SILCZNOIICM7218/1ICM7228 8 Digit LED Display Driver Pin Configurations Top View 28 Pin DIP 28 Pin DIP I stcc Je id [28] GROUND giGiT4 Lr Je [28] GROUND SEGE [2] [27] SEGA oisiT 6 C2] [ 27} oiGit 7 SEG 8 (3 | [26] SEG G oiciT 3 (3 26} DIGIT 5 op [4] (25) SEG 0 DIGIT 1 25] DIGIT 2 1D6 |HEXA/CODE 8) [5 | [ 24) SEG F 106 (HEXA/CODE 8] [5 [24] DiGlT 8 10s (DECODE) (6 | [23] OlGIT 3 (D5 (DECOOE) (6 | [23] SEG G 107 {DATA COMING) [7] AMAXIAA [2 DIGITS 107 (DATA COMING) [7] ANAAXIMM [27) sec F waite [8] fcm7278A [Qi oir? write [8] = /CM7218B [21] SEGE move [3] [20] oiGiT 4 MODE [3 | 20] SEGC (04 (SHUTDOWN) [10] its 104 (SHUTDOWN) (10 | wey to) 0] (18) DIGIT 8 1 (4 [18] SEG D (00 [12] Pi7) BtGiT 5 10 [72 | 17] SEG B (D2 [73] [16] DIGIT 2 (02 [73] [76] SEGA 103 [14] [15] oiGiT | 103 [14] ris} oP 28 Pin DIP 28 Pin DIP TT TST segc fi je 28] GROUND agita Li je 28} GROUND SEGE [2 [ 27) SEGA DIGIT 6 [ 27) oGit 7 sec B [3 | [ 26) SEG G plgiT 3 [3 [26] OIGIT S ope 4] [ 25) SEG D oigiT 1 [a [25] OIGIT 2 DAO (OIGIT ADDRESS 0) (4 J [ 24] SEG F OAO (DIGIT ADDRESS 0) (5 ] 24} OIGIT 8 DAI (DIGIT ADORESS 1) [6 | [23] O1GIT 3 DA} (DIGIT ADDRESS 1 [6 | 23) SEG G ny INPUT OP) [7] ANAXIM [22] oiT 6 [D7 (INPUT DP) [7] AAAKIM [7] seer write (8) 7CM721eC [2 oir? write [8] 1CM7218D [21] sece HEXA/CODE B/SHUTDOWN [9 | [20] OlGIT 4 HEXA/CODE B/SHUTOOWN [3 | [20] SEG C DA2 (DIGIT ADDRESS 2) [10 | igjv DA2 (DIGIT ADDRESS 2) [10 | Pig} v i 0 (18) ocit 8 i OY 18] SEG D ino [72 [17] piGiT 5 a TT] SEG B in2 [73 [16] ovGit 2 ioz 013] TE} SEGA 103 [74 [15] OIGIT 1 103 [14] [15] oP __ Ordering Information (continued) [25] PART TEMP. RANGE PACKAGE MAXI es ICM7218AI/D -20C to +85C Dice 23 MAX7218A/B/C/D [22] ICM7218AIQ1 -20C to +85C 28 Lead Quad Pack [21 | 1CM7218BI/D -20C to +85C Dice SEE DIP DRAWINGS [20] ICM7218BIQ1 ~20C to +85C 28 Lead Quad Pack FOR PIN LABELS [19] - ICM7218CI/D -20C to +85C Dice ICM7218CIQ1 -20C to +85C 28 Lead Quad Pack ICM7218DI/D -20C to +85C Dice 28 Lead Quad Pack ICM7218DIQl -20C to +85C 28 Lead Quad Pack Maxim cannot assume responsibility for use of any ccuitry other than circuilry entirely embodied in a Maxim product. No cucu pefent feanses are iniphod. Maxim reserves the right to change the circuitry and ifications without! notice at any ume. 12 Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 Printed USA MAXIM is a registered trademark of Maxim Integrated Products 1996 Maxim Integrated Products