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1/12 april 2004 m5450 m5451 led display drivers rev. 2 features summary m5450 34 outputs/15ma sink m5451 35 outputs/15ma sink current generator outputs (no external resistors required) continuous brightness control serial data input enable (on m5450) wide supply voltage operation ttl compatibility application examples: microprocessor displays industrial control indicator relay driver instrumentation readouts description the m5450 and m5451 are monolithic mos inte- grated circuits produced wi th an n-channel silicon gate technology. they are available in 40-pin dual in-line plastic packages. a single pin controls the led display brightness by setting a reference current through a variable re- sistor connected to v dd or to a separate supply of 13.2v maximum. figure 1. packages 1 40 plcc44 (plastic chip carrier) pdip40 (plastic package) obsolete product(s) - obsolete product(s)
m5450, m5451 2/12 figure 2. pin connection figure 3. block diagram 1 2 3 4 5 6 7 8 9 10 11 12 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 13 14 15 16 17 18 19 20 24 23 22 21 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 output bit 18 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 data enable for m5450 output bit 35 for m5451 data in clock in v dd v ss 18 19 20 21 22 23 24 25 26 27 28 9 10 11 12 13 14 15 16 17 29 30 31 32 33 34 35 36 37 7 8 38 39 40 41 42 43 44 1 2 3 4 5 6 output bit 13 output bit 12 output bit 11 output bit 10 output bit 9 output bit 8 output bit 7 n.c. output bit 6 output bit 32 n.c. output bit 31 output bit 30 output bit 29 output bit 28 output bit 27 output bit 26 output bit 25 output bit 24 output bit 23 n.c output bit 35 output bit 2 output bit 1 brightness control clock in data in output bit 5 output bit 4 v dd output bit 3 output bit 34 output bit 33 output bit 14 output bit 15 output bit 16 output bit 17 output bit 18 output bit 19 output bit 20 output bit 21 output bit 22 v ss n.c 35 output buffers 1 18 19 20 24 v dd 35 latches 35-bit shift register 21 22 23 reset load serial data clock data enable (m5450) output35 (5451) brigthness control output bit 34 100k ? output bit 1 obsolete product(s) - obsolete product(s)
3/12 m5450, m5451 table 1. absolute maximum ratings note: stresses above those listed under "absolute maximum ratings" may causes permanent damage to the device. this is a stress r ating only and functional operation of the device at these or any other conditions above 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 . functional description both the m5450 and the m5451 are specially de- signed to operate 4 or 5-digit alphanumeric dis- plays 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 led displays. a 1nf capacitor should be connected to bright- ness control, pin 19, to prevent possible oscilla- tions. a block diagram is shown in figure 3. for the m5450 a data enable is used instead of the 35th output. the data enable input is a metal option for the m5450. the output current is typically 20 times greater than the current into pin 19, which is set by an ex- ternal variable resistor. there is an internal limiting resistor of 400w 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. 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 al- lowing 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. bit 1 is the first bit followi ng 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 relationship between data, clock and data enable . a max 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 calcula- tions. t j = [(v out ) (i led ) (no. of segments) + (v dd 7ma)] (124c/w) + t amb where : t j = junction temperature (150c max) v out = the voltage at the led driver outputs i led = the led current 124c/w = thermal coefficient of the package t amb = ambient temperature the above equation was used to plot figure 6, fig- ure 7 and figure 8. symbol parameter value unit v dd supply voltage ? 0.3 to 15 v v i input voltage ? 0.3 to 15 v v o(off) off state output voltage 15 v i o output sink current 40 ma p tot total package power dissipation at 25c 1 w total package power dissipation at 85c 560 mw t j junction temperature 150 c t op operating temperature range ? 25 to 85 c t stg storage temperature range ? 65 to 150 c obsolete product(s) - obsolete product(s)
m5450, m5451 4/12 table 2. static electrical characteristics (t amb within operating range, v dd = 4.75v to 13.2v, v ss = 0v, unless otherwise specified) note: 1. output matching is calculated as the percent variation from i max + i min /2. 2. with a fixed resistor on the brightness input some variation in brightness will occur from one device to another. 3. absolute maximum for each output should be limited to 40ma. 4. the v o voltage should be regulated by the user. see figure 7 and figure 8 for allowable vo versus io operation. figure 4. input data format symbol parameter test conditions min. typ. max. unit v dd supply voltage 4 .75 13.2 v i dd supply current v dd = 13.2v 7ma v i input voltage logical "0" level 10a input bias - 0.3 0.8 v logical "1" level 4.75 v dd 5.25 2.2 v dd v v dd > 5.25 v dd - 2 v dd v i b brightness input curr ent (note 2) 0 0 . 75 ma v b brightness input voltage (pin 19) input current = 750 a, t amb = 25 c 34 . 3v v o(off) off state out. voltage 13. 2 v i o out. sink current (note 3) segment off v o = 3v 10 a segment on v o = 1v (note 4) brightness in. = 0 a010 a brightness in. = 100 2 2 7 4 m a brightness in. = 750 a121525ma f clock input clock frequency 0 0.5 mhz i o output matching (note 1) 20 % 36 bit 34 clock data load (internal) reset (internal) start bit 1 1 bit 35 obsolete product(s) - obsolete product(s)
5/12 m5450, m5451 figure 5. figure 6. figure 7. figure 8. clock data 300ns (min.) 100ns (min.) data enable 1.0 0.8 0.6 0.4 0.2 20 40 60 80 100 safe operating area 34 segments v = 1v o 15ma/segment p (w) tot 0 t amb (?c) 4 812162024 0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 28 32 t amb = 85?c t j = 150?c (max.) ? v o (v) i led (ma) 20 segments 30 segments 34 segments 48 12 16 20 24 28 32 36 40 0 45 65 85 105 i 0 (ma) t amb = 85?c n? segm. 5 25 v o = 1v i o (max.) = 40ma v o = 1.5v v o = 2v obsolete product(s) - obsolete product(s)
m5450, m5451 6/12 typical applications figure 9. basic electronicall y tuned radio or tv system figure 10. duplexing 8 di gits with one m5450 am fm 34 segments m5450 display driver electronic tuning controller station detec. etc. keyboard pll synthesizer m5450 21 18 22 19 17 20 1 23 v dd data in brightness control v led v dd 916 2840 3239 2431 . . . .... . clock in v led v dd obsolete product(s) - obsolete product(s)
7/12 m5450, m5451 power dissipation of the ic the power dissipation of the ic can be limited us- ing different configurations. figure 11- in the application r must be chosen taking into account the worst operating conditions. figure 11. r is determined by the maximum number of seg- ments activated 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 re sistors can be used in con- junction with groups of segments. in this case the current variation in the single resis- tor is reduced and p tot limited. figure 12 - in this configuration the drop on the se- rial connected diodes is quite stable if the diodes are properly chosen. the total power dissipation of the ic depends, in a first approximation, only on the number of seg- ments activated. figure 12. figure 13 - in this configuration v out + v d is con- stant. the total power dissipation of the ic de- pends only on the number of segments activated. figure 13. v d v out r i d +v c r v c v dmax ? v omin ? n max l d ---------------------------------------------------------------- = +v c +v c v out +v d obsolete product(s) - obsolete product(s)
m5450, m5451 8/12 part numbering table 3. order codes part number package temperature range m5450b7/m5451b7 pdip40 -25 to 85 c m5451q plcc44 -25 to 85 c obsolete product(s) - obsolete product(s)
9/12 m5450, m5451 package mechanical table 4. pdip40 - mechanical data figure 14. pdip40 - package dimensions note: drawing is not to scale symbol millimeters inches typ min max typ min max a1 0.63 0.025 b 0.45 0.018 b1 0.23 0.31 0.009 0.012 b2 1.27 0.050 d 52.58 2.070 e 15.2 16.68 0.598 0.657 e 2.54 0.100 e3 48.26 1.900 f 14.1 0.555 i 4.445 0.175 l 3.3 0.130 40 i a1 l b2 e d e3 f b1 e 21 120 b obsolete product(s) - obsolete product(s)
m5450, m5451 10/12 table 5. plcc44 - mechanical data figure 15. plcc44 - package dimensions note: drawing is not to scale. symbol millimeters inches typ min max typ min max a 17.4 17.65 0.685 0.695 b 16.51 16.65 0.650 0.656 c 3.65 3.7 0.144 0.146 d 4.2 4.57 0.165 0.180 d1 2.59 2.74 0.102 0.108 d2 0.68 0.027 e 14.99 16 0.590 0.630 e 1.27 0.050 e3 12.7 0.500 f 0.46 0.018 f1 0.71 0.028 g 0.101 0.004 m 1.16 0.046 m1 1.14 0.045 39 44 6 21 d d1 d2 c m m f e f1 e3 e b m1 a m1 g (seating plane coplanarity) 38 7 18 29 28 17 obsolete product(s) - obsolete product(s)
11/12 m5450, m5451 revision history table 6. revision history date revision description of changes september-1993 1 first issue 14-mar-2004 2 stylesheet update. no content change. obsolete product(s) - obsolete product(s)
m5450, m5451 12/12 information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the co nsequences 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 publicati on are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectronics prod ucts are not authorized for use as critical components in life support devices or systems without express written approval of stmicroelectro nics. 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 - ital y - japan - malaysia - malta - morocco - singapore - spain - sweden - switzerland - united kingdom - united states www.st.com obsolete product(s) - obsolete product(s)

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