mm5450/5451 micrel may 2000 1 mm5450/5451 mm5450/5451 led display driver general description the mm5450 and mm5451 led display drivers are monolithic mos ic? 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 870 01 figure 1. 35 output buffers 35 latches 35-bit shift registers load reset reset (only available in die form) serial data 22 cloc k 21 data enable/out 35 (see note 1) 23 19 20 24 out 34 18 out 1 1 brightness contro l vdd note 1: pin 23 is data enable in mm5450 pin 23 is output 35 in mm5451 block diagram micrel, inc. ?1849 fortune drive ?san jose, ca 95131 ?usa ?tel + 1 (408) 944-0800 ?fax + 1 (408) 944-0970 ?http://www.mic rel.com ordering information part number junction temp. range package mm5450bn 40 c to +85 c 40-pin plastic dip mm5451bn 40 c to +85 c 40-pin plastic dip mm5450bv 40 c to +85 c 44-pin plcc mm5451bv 40 c to +85 c 44-pin plcc
mm5450/5451 micrel mm5450/5451 2 may 2000 connection diagram: die figure 3a, 3b. note: die size is 0.106" x 0.099" connection diagram: dual-in-line package figure 2. v output bit 24 enable data clk brightness control reset mm5450/5451 die pinout 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 1 output bit 2 output bit 35 output bit 34 v dd ss v ss 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 v ss output bit 13 output bit 14 output bit 15 output bit 16 output bit 17 output bit 1 8 output bit 1 9 output bit 2 0 output bit 21 output bit 2 2 output bit 2 3 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 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 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
mm5450/5451 micrel may 2000 3 mm5450/5451 connection diagram: plastic leaded chip carrier figure 4a, 4b. 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 v ss output bit 14 output bit 15 output bit 16 output bit 17 output bit 13 output bit 23 nc 6 44 43 42 41 40 nc output bit 18 output bit 19 output bit 20 output bit 21 22 21 20 19 18 24 25 26 27 28 output bit 22 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 v ss output bit 14 output bit 15 output bit 16 output bit 17 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 nc output bit 18 output bit 19 output bit 20 output bit 21 output bit 3 output bit 2 output bit 1 brightness control nc clock in data in data enable output bit 34 output bit 33 23 22 21 20 19 18 24 25 26 27 28 output bit 22 v dd
mm5450/5451 micrel mm5450/5451 4 may 2000 absolute maximum ratings voltage (any pin) ...................................... v ss to v ss +12v power dissipation (p d ) +25 c ......................................................................... 1w +85 c .................................................................. 560mw junction temperature (t j ) ...................................... +150 c storage temperature (t s ) ....................... 65 c to +150 c lead temperature (soldering, 10 sec.) ................... +300 c operating ratings supply voltage (v dd v ss ) ....................... +4.75v to +11v ambient temperature range (t a ) ............. 40 c to +85 c electrical characteristics 4.5v v dd 11v, v ss = 0v; t a = 25 c, bold values indicate 40 c t a +85 c; unless noted symbol parameter condition min typ max units power supply current 25 c to +85 c, excluding output loads 8.5 ma 40 c to +85 c, excluding output loads 10 ma data input voltage v l logic-0 level, 10 a input bias ?.3 0.8 v v h logic-1 level, 4.75v v dd 5.25v 2.2 v dd v v dd > 5.25v v dd ? v dd v brightness control input current note 2 0 0.75 ma output sink current segment off, v out = 3.0v 10 a segment on, v out = 1.0v, note 3 brightness input = 0 a 010 a brightness input = 100 a 2.0 2.7 4 ma brightness input = 750 a 15 25 ma brightness control input voltage 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 time 300 ns t des data enable input setup time 100 ns reset pad current die 8 a note 1: output matching is calculated as the percent variation (i max + i min ) 2. note 2: with a fixed resistor on the brightness input pin, some variation in brightness will occur among devices. maximum brightness control input current can be 2ma providing it complies with note 3 and the junction temperature equation. note 3: see figures 7, 8 and 9 for recommended operating conditions and limits. absolute maximum for each output should be limited to 40ma. note 4: v out should be regulated by the user. see figures 8 and 9 for allowable v out vs. i out operation. note 5: ac input waveform specification for test purpose: t r 20ns, t f 20ns, f = 500khz, 50% 10% duty cycle. note 6: clock input rise and fall times must not exceed 300ns.
mm5450/5451 micrel may 2000 5 mm5450/5451 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 interface 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 followed 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 display. characters currently displayed (thus, data output) changes only if the serial data bits differ from those previously transferred. 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. this 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 pin-out of the mic5450 and mic5451. bit 1 is the first bit following the start bit and it will appear on pin 18. a logical 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 either 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) (124 c/w) + t a where: t j = junction temperature + 150 c max v out = the voltage at the led driver outputs i led = the led current 124 c/w = thermal resistance of the package t a = ambient temperature the above equation was used to plot figures 7 9. figure 5. clock data data enable 300 ns min 100 ns min clock 1 data load (internal) reset (internal) start bit 1 bit 36 36 37 bit 35 figure 6. input data format
mm5450/5451 micrel mm5450/5451 6 may 2000 typical performance characteristics typical applications figure 10. typical application of constant current brightness control cd4046 (vco) 5v mm74hc123 10 s mm5450 q19 20 1 figure 11. brightness control varying the duty cycle figure 7. figure 8. 2.5 2.0 1.5 1.0 0.5 0 0481216202428 i (ma) led v (v ) out o t = 85 c t = 150 c (max) a j 20 seg m 30 segm 34 segm 1.0 0.8 0.6 0.4 0.2 0 020406080 temperature ( c) power dissipation (w) 34 segments v = 1v 15 ma/segment out safe operating area 100 figure 9. 110 100 90 80 70 60 50 40 30 20 10 0 0 5 10 15 20 25 30 34 number of segments output current (ma) v = 1v out v = 1.5v out v = 2v out t = 85 c a lm324 mm5450 lm317 + ? v 240 ? raw dc > 9 v ? v 1k i 19 = 2n2907 i 19 pin 19 5v 20 1 5k 7v 1k
mm5450/5451 micrel may 2000 7 mm5450/5451 typical applications figure 12. basic electronically tuned radio system figure 13. duplexing 8 digits with one mm5450. led display 34 mm5450 display driver electronic tuning controller pll synthesizer keyboard station detect, etc. am fm 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
mm5450/5451 micrel mm5450/5451 8 may 2000 micrel inc. 1849 fortune drive san jose, ca 95131 usa tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 web http://www.micrel.com this information is believed to be accurate and reliable, however no responsibility is assumed by micrel for its use nor for an y infringement of patents or other rights of third parties resulting from its use. no license is granted by implication or otherwise under any patent or pat ent right of micrel inc. ? 2000 micrel incorporated package information 2.040 .100 .150 .075 .125 min .018 typ .060 .002 .100 typ .020 min .010 .625 .025 105 /90 .030 nom .546 .010 .080 nom 1 40 20 21 40-pin plastic dip (n) top view 0.690 0.005 0.652 .610 .015 0.050 typ non-accum 0.045 0.045 0.094 0.015 0.137 typ 0.125 dia x 0.005 deep 4 plcs (ejector pin) bottom view 0.045 0.045 0.035 r 0.010 0.062 dia x 0.020 deep detail a 0.020 min 0.104 0.172 detail a 0.062 typ 0.030 typ 0.018 0.104 0.028 side view 44-pin plcc (v)
|
