mm5450/5451 led display driver superswitcher and super ?eta pnp are trademarks of micrel, inc. micrel inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel +1 ( 408 ) 944-0800 ? fax + 1 (408) 474-1000 ? http://www.micrel.com february 2006 m9999-021606 (408) 955-1690 general description the mm5450 and mm5451 led display drivers are monolithic mos ic?s fabricated in an n-channel, metal- gate process. the technology produces low-threshold, enhancement-mode, and ion-implanted depletion-mode devices. a single pin controls the led display brightness by setting a reference current through a variable resistor connected to the supply. applications ? industrial control indicator ? relay driver ? digital clock, thermometer, counter, voltmeter ? instrumentation readouts features ? continuous brightness control ? serial data input ? no load signal requirement ? enable (on mm5450) ? wide power supply operation ? ttl compatibility ? 34 or 35 outputs, 15ma capability ? alphanumeric capability ordering information part number standard pb-free junction temp. range package mm5450bn mm5450yn ?40c to+85c 40-pin pdip mm5451bn mm5451yn ?40c to+85c 40-pin pdip mm5450bv mm5450yv ?40c to+85c 44-pin plcc mm5451bv mm5451yv ?40c to+85c 44-pin plcc ____________________________________________________________________________________________________________ block diagram 35 output buffers 35 latches 35-bit shift register load reset reset (only available in die form) serial data 22 clock 21 data enable/out 35 (see note 1) 23 19 20 24 out 34 18 out 1 1 brightness control vdd note 1: pin 23 is data enable in mm5450 pin 23 is output 35 in mm5451 figure 1.
micrel, inc. mm5450/5451 february 2006 2 m9999-021606 (408) 955-1690 connection diagram: die figure 2. connection diagram: dual-in-line package 1 40 2 39 3 38 4 37 5 36 6 35 7 34 8 33 9 32 10 31 11 30 12 29 13 28 14 27 15 26 16 25 17 24 18 23 19 22 20 21 output bit 18 clock in mm5450bn/yn v ss v dd output bit 17 output bit 16 output bit 15 output bit 14 output bit 13 output bit 12 output bit 11 output bit 10 output bit 9 output bit 8 output bit 7 output bit 6 output bit 5 output bit 4 output bit 3 output bit 2 output bit 1 brightness control data in data enable output bit 19 output bit 20 output bit 21 output bit 22 output bit 23 output bit 24 output bit 25 output bit 26 output bit 27 output bit 28 output bit 29 output bit 30 output bit 31 output bit 32 output bit 33 output bit 34 1 40 2 39 3 38 4 37 5 36 6 35 7 34 8 33 9 32 10 31 11 30 12 29 13 28 14 27 15 26 16 25 17 24 18 23 19 22 20 21 output bit 18 clock in mm5451bn/yn v ss v dd output bit 17 output bit 16 output bit 15 output bit 14 output bit 13 output bit 12 output bit 11 output bit 10 output bit 9 output bit 8 output bit 7 output bit 6 output bit 5 output bit 4 output bit 3 output bit 2 output bit 1 brightness control data in output bit 19 output bit 20 output bit 21 output bit 22 output bit 23 output bit 24 output bit 25 output bit 26 output bit 27 output bit 28 output bit 29 output bit 30 output bit 31 output bit 32 output bit 33 output bit 34 output bit 35 figure 3a, 3b.
micrel, inc. mm5450/5451 february 2006 3 m9999-021606 (408) 955-1690 connection diagram: plastic leaded chip carrier 1 2 39 3 38 4 37 5 36 7 35 8 34 9 33 10 32 11 31 12 30 13 29 14 15 16 17 mm5451bv/yv output bit 13 output bit 12 output bit 11 output bit 10 output bit 9 output bit 8 output bit 7 output bit 6 output bit 5 output bit 4 output bit 23 output bit 24 output bit 25 output bit 26 output bit 27 nc output bit 28 output bit 29 output bit 30 output bit 31 output bit 32 nc 6 44 43 42 41 40 23 22 21 20 19 18 24 25 26 27 28 1 2 39 3 38 4 37 5 36 7 35 8 34 9 33 10 32 11 31 12 30 13 29 14 15 16 17 mm5450bv/yv output bit 13 output bit 12 output bit 11 output bit 10 output bit 9 output bit 8 output bit 7 output bit 6 output bit 5 output bit 4 output bit 23 output bit 24 output bit 25 output bit 26 output bit 27 nc output bit 28 output bit 29 output bit 30 output bit 31 output bit 32 nc 6 44 43 42 41 40 23 22 21 20 19 18 24 25 26 27 28 figure 4a, 4b.
micrel, inc. mm5450/5451 february 2006 4 m9999-021606 (408) 955-1690 absolute maximum ratings voltage (any pin) ........................................v ss to v ss + 12v power dissipation +25c........................................................................1w +85c .................................................................560m w junction temperature (t j ) ....................................... +150c storage temperature (t s ).........................?65c to +150c lead temperature (solderi ng, 10sec.) ..................... +300c operating ratings supply voltage (v dd ? v ss ).......................... +4.75v to +11v ambient temperature range (t a ) ............. ?40c to +85c electrical characteristics 4.5v v dd 11v, v ss = 0v; t a = 25c, bold values indicate ?40c t a +85c, unless otherwise noted. symbol parameter condition min typ max units power supply current ?25c to +85c, excluding output loads ?40c to +85c, excluding output loads 8.5 10 ma ma v l v h data input voltage logic-0 level, 10 a input bias logic-1 level, 4.75v v dd 5.25v v dd > 5.25v ?0.3 2.2 v dd ?2 0.8 v dd v dd v v v brightness control input current note 2 0 0.75 ma segment off, v out = 3.0v 10 a output sink current segment on, v out = 1.8v, note 3 brightness input = 0a brightness input = 100a brightness input = 750a 0 2.0 15 2.7 10 4 25 a ma ma brightness control input v oltage input current = 750 a 3.0 4.3 v output matching note 1 20 % f c clock input frequency notes 5, 6 500 khz t h clock input high time notes 5, 6 950 ns t l clock input low time notes 5, 6 950 ns t ds data input setup time 300 ns t dh data input hold setup time 300 ns t des data enable input setup time 100 ns reset pad current die 8 8 a notes: 1. output matching is calcul ated as the percent variation (i max + i min ) / 2. 2. with a fixed resistor on the brightness input pin, some variation in brightness will occur among devices. 3. see figures 7, 8 and 9 for recommended operating conditions and limits. absolute maximum for each output should be limited to 40ma. 4. v out should be regulated by user. see figures 8 and 9 for allowable v out vs. i out operation. 5. ac input waveform specification for test purpose: t r 200ns, t f 20ns, f = 500khz, 50% 10% duty cycle. 6. clock input rise and fall times must not exceed 300ns.
micrel, inc. mm5450/5451 february 2006 5 m9999-021606 (408) 955-1690 functional description the mm5450 and mm5451 were designed to drive either 4- or 5-digit alphanumeric led displays with the added benefit of requiring minimal in terface with the display or data source. data is transferred serially via 2 signals; clock and serial data. data transfer without the added inconvenience of an external load signal is accomplished by using a format of a leading ?1?follo wed by the allowed 35 data bits. these 35 data bits are latched after the 36th has been transferred. this scheme provides non multiplexed, direct drive to the led disp lay. characters currently displayed (thus, data output) changes only if the serial data bits differ from those previously transferred. the mic37252 regulator is fully protected from damage due to fault conditions. current limiting is provided. this limiting is linear; output current during overload conditions is constant. thermal shutdown disables the device when the die temperature exceeds the maximum safe operating temperature. transient protection allows device (and load) survival ev en when the input voltage spikes above and below nominal. the output structure of these regulators allows voltages in excess of the desired output voltage to be applied wi thout reverse current flow. control of the output current for led displays provides for the display brightness. to prevent oscillations, a 1nf capacitor should be connected to pin 19, brightness control. the block diagram is shown in figure 1. for the mic5450, the /data enable is a metal option and is used instead of the 35th output. the output current is typically 20-times greater that the current into pin 19, which is set by an external variable resistor. there is an external reset connection shown which is available on unpackaged (die ) only. figure 2 illustrates the die pad locations for bonding in ?chip on board? applications. figure 5 shows the input data format. a leading ?1? is followed by 35 bits of data. after the 36th had been transferred, a load signal is generated synchronously with the clock high state. th is loads the 35 bits of data into the latches. the low side of the clock is used to generate a reset signal which clears all shift registers for the next set of data. all shift registers are static master-slave, with no clear for the master portion of the first register, allowing continuous operation. there must be a complete set of 36 clocks or the shift registers will not clear. when the chip first powers on, 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 3 and 4 show the pi nout of the mic5450 and mic5451. bit 1 is the first bit following the start bit and it will appear on pin 18. a logica l ?1? at the input will turn on the appropriate led. figure 5 shows the timing relationships between data, clock and /data enable. a maximum clock frequency of 0.5mhz is assumed. for applications where a lesser number of outputs are used, it is possible to eit her increase the current per output, or operate the part at higher than 1v v out . the following equation can be used for calculations. t j = (v out ) (i led ) (no. of segments) (124c/w) + t a where: t j = junction temperature + 150c max v out = the voltage at the led driver outputs i led = the led current 124c/w = thermal resistance of the package t a = ambient temperature the above equation was used to plot figures 7?9.
micrel, inc. mm5450/5451 february 2006 6 m9999-021606 (408) 955-1690 figure 5. figure 6. input data format
micrel, inc. mm5450/5451 february 2006 7 m9999-021606 (408) 955-1690 typical performance characteristics figure 7. figure 8. led o t u o a j g e s 0 2 m figure 9. typical applications lm324 mm5450 lm317 ? + 240 raw dc > 9 v 1k i 19 = 2n2907 i 19 pin 19 5v 20 1 5k 7v 1k cd4046 (vco) 5v mm74hc123 10 s mm5450 q19 20 1 figure 10. typical application of constant current figure 11. brightness control varying the duty cycle brightness control
micrel, inc. mm5450/5451 february 2006 8 m9999-021606 (408) 955-1690 typical applications led display 34 mm5450 display driver electronic tuning controller pll synthesizer keyboard station detect, etc. am fm figure 12. basic electroni cally tuned radio system 9?16 2?8, 40 32?39 24?31 18 21 22 19 20 1 23 17 100k typ. mm5450 v led v led v led =3.0v v led =3.0v clock in data in v dd brightness control figure 13. duplexing 8 digits with one mm5450
micrel, inc. mm5450/5451 february 2006 9 m9999-021606 (408) 955-1690 package information 40-pin plastic dip (n) 44-pin plcc (v) micrel, inc. 2180 fortune drive san jose, ca 95131 usa tel +1 (408) 944-0800 fax +1 (408) 474-1000 web http:/www.micrel.com the information furnished by micrel in this data sheet is belie ved to be accurate and reliable. however, no responsibility is a ssumed by micrel for its use. micrel reserves the right to change circuitry and specifications at any time without notification to the customer. micrel products are not designed or authori zed for use as components in life support app liances, devices or systems where malfu nction of a product can reasonably be expected to result in personal injury. life suppo rt devices or systems are devices or systems that (a) are in tended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significan t injury to the user. a purchaser?s use or sale of micrel produc ts for use in life support app liances, devices or systems is a purchaser?s own risk and purchaser agrees to fully indemnify micrel for any damages resulting from such use or sale. ? 2002 micrel, incorporated.
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