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[ak7864 a ] ms1336 - e - 00 1 20 12 / 01 ak7864 a 3 channel led driver with charge pump device outline this product include s the charge pump power supply and the 3 channel led driver who drives the led of the anode common in the constant current . the current to pass for each channel can be adj usted by the external resistance and the register setting. also, it has the control pins which turn on or off the current . it is the suitable for the led drive for the cis sensor. features operat ing voltage 3.3v5% operating temperature range 0 ~ 70 ? c led d river c urrent red : 66 ma green: 66ma blue: 66ma the led current is adjustable from 22ma to 66ma by the external resistor. in addition, t he led current can be reduced to 100%~12.5% by the register. allowable maximum vf of the led is 4.8v. the 1/16 watt typ e is usable to external resistor. ? 3 chnnel independent ly on/off ( 50% setting is an upper bound when 3ch becoming turning on at the same time ) ? current setting in eight st ep s when the external resistance value becomes the assumption outside, a i nternal prote ction circuit restricts the led current equal to or less than 150ma ( - 30% ~ +45% ) current accuracy 9. 1 % by ideal resis t ance led current r ise / f all i ime 10 ? s (typ.) (10% ~ 90%) charge p ump p ressor c ircuit generate the necessary voltage for the led vf max 4.8v package 16pin qfn 3mm ? 3mm , 0.75mm thickness with radiation tab in s olderside power supply vdd 3.135 ~ 3.465 v application a light source driver for cis module of mfp
[ak7864 a ] ms1336 - e - 00 2 20 12 / 01 block diagram circuit block description ? charge pump circuit a necessary voltage for led (vf 4.8v or less) lighting is generated from the voltage supplied to vdd pin. please s upply the generated voltage from cpout pin to external led. ? led driver part this product has 3 channel led driver to drive rgb consta nt current. use the on/ off digital terminal to control the constant current. the curren t setting can be set to 8 level s (100%/87.5%/75%/62.5%/50%/37.5%/25%/12.5%) with cont_r/g/b and en combination. the current of 3 channels are same. it is possible to li ght 1ch or 3ch simultaneously. please set the led current less than 50% by 3ch simultaneously. cpout led_r vdd (3.3v5%) c po current source r c p1 current setting 8 step sw r ? 1% cc charge pump (vdd ? current source g current source b led_g led_b sw sw cont_r cont_ g cont_b vss en iref pd n cp c n
[ak7864 a ] ms1336 - e - 00 3 20 12 / 01 functional description ? power down set pdn to low at vdd power on, AK7864A will be in power down state. in power down state, the current inside AK7864A will be stop ped , led_r/g/b will be high - z and cpout will be low. ? circuit reset pd n is also carrying out the reset of an internal counter , please start supplying vdd to AK7864A by pdn=l ow . the period of soft start of charge pump is decided at the internal counte r. when soft start does not operate correctly, at the time o f starting, incoming current will be large and the device may break.
[ak7864 a ] ms1336 - e - 00 4 20 12 / 01 ? cur rent setting method the method of setting the led current is as follows. latch the logic level o f cont_ r , cont_ g , cont_ b at the en rise . this logic pattern decide s the current level . after the falling edge of the cont_ r , cont_ g , cont_ b, the led current interlocks with cont_ r , cont_ g , cont_ b s on or off . en cont_r cont_g cont_b the relation between the cont_ r , cont_ g , cont_ b pattern and the current level follows. cont_ r cont_ g cont_ b current setting 0 0 0 100% 0 0 1 87.5% 0 1 0 75% 0 1 1 62.5% 1 0 0 50% 1 0 1 37.5% 1 1 0 25% 1 1 1 12.5% after first fall, led is on with en high period. the current level is set here turn rgb on not turn on
[ak7864 a ] ms1336 - e - 00 5 20 12 / 01 pin allocation 13 14 15 16 8 7 6 5 4 3 2 1 cp cn led_b cont_r cont_g 9 10 11 12 vss iref vdd en pdn ak7864 a led_r cpout vss vss led_g cont_b top view
[ak7864 a ] ms1336 - e - 00 6 20 12 / 01 pin functions no. name io description 1 vdd p p ower supply 2 iref o led current setting exter nal resist o r connecting pin (pulled down by external resistor at power down) 3 pdn i power down mode terminal hi gh : power up, lo w : power down 4 en i led current enable terminal hi gh : enable, lo w : disable 5 cont_b i led current control input for led_ b high: on, low: off 6 cont_g i led current control input for led_ g high: on, low: off 7 con t _r i led current control input for led_ r high: on, low: off 8 led_b o led current output pin b ( hi gh - z at p ower down) 9 vss p gnd 10 led_g o led current output pin g ( hi gh - z at p ower down) 11 vss p gnd 12 led_r o led current output pin r ( hi gh - z at p ower down) 13 cpout o charge pump out put pin (pulled down by internal resistor at power down) 14 vss p gnd 15 cp i external capacitor connecting pin for c harge pump (pulled down by internal resistor at power down) 16 cn i external capacitor connecting pin for c harge pump (pulled down by inter nal resistor at power down) radiation pad connect to gnd. i: input, o: output, p: power supply
[ak7864 a ] ms1336 - e - 00 7 20 12 / 01 absolute maximum ratings voltages are referenced to corresponding ground level. vss=0v item symbol min. max. unit remarks power supply vdd ? ? ? ? recommended ope rating conditions voltages are referenced to corresponding ground level. vss=0v item symbol min. typ. max. unit remarks power supply vdd 3.135 3.3 3 .465 v storage temperature ta 0 70 ? electrical characteristics 1. digital input dc characteristics (v dd=3.135~3.465v , ta=0 ? 70 ? c unless otherwise specified ) item symbol pin min. typ. max. unit remarks h level input voltage vih note 1 0.7 ? ? ? ? 2. c arge pump b lock a nalog characteristics (vdd=3.135~3.465v , ta=0 ? 70 ? c unless otherwise specified ) item min. typ. max. unit remarks cpout voltage 6.27 6.6 6.93 v @ led current disable cpout rise time 1 m s cpout fall time 20 ms current consumption 4.0 m a
[ak7864 a ] ms1336 - e - 00 8 20 12 / 01 3. led driver block a nalog characteristics (vdd=3.135~3.465v , ta=0 ? 70 ? c unless otherwise specified ) item min. typ. max. unit remarks led drive current range 22 66 ma ( note 1 ) the led protection circuit activation current 1 05 150 217.5 ma led current (r/g/b) 60 66 72 ma iref resist o r =4.7 k ? 2 ? v dd C 3.1 v led current accuracy (r/g/b) 86.0 73.5 60.5 48 35.5 23 10.5 100 87.5 75 62.5 50 37.5 25 12.5 89.0 76.5 64.5 52 39.5 27 14.5 % % % % % % % % le d pin voltage = 2 ? vdd C 3.1 v cont_r/g/b 000 001 010 011 100 101 110 111 led current led vf dependency ? 2 ? vdd C 3.1 ) v led vf 1. 1 4.8 v (note 2 ) current consumption 1.1 ma except led drive current ( note 1 ) iref resist ance [ k ? ] 66 [led drive current [ ma ] ] 4.7 [ k ? ]. [led drive current ] is possible to be set to 22ma ~ 66ma. (note 2) in order to keep the normal operation at generation of heat of device, when rgb 3ch simultaneous lighting, the minimum of vf has restriction. ex ample: (when 3c h simultaneous lighting with drive current 33ma , as f or the minimum of vf, in 1ch 1.1v and the remaining 2 ch are 2.0v) when you use simultan eous lighting, since we can check for you whether led vf combination to use of a drive curren t value are possible, please contact us. (note 3 ) external load: the total line resistance of cpout pin ~ led anode and led cathode ~ led_r/g/g pin must be within 2 ? . ( note 4 ) 50% setting is an upper bound when all channels turn on at the same time.
[ak7864 a ] ms1336 - e - 00 9 20 12 / 01 4. l edd block, s witching characteristics en contr/g/b ( high setting ) contr/g/b ( low setting ) led current (vdd=3.135~3.465v , ta=0 ? 70 ? c, unless otherwise specified) no. item min. typ. max. unit co nditions tlon led current rise time 10 ? ? ? ? ? 0.7vdd 0.7vdd 0.3vdd 0.7vdd 90% tloff 10% th tcl 0.3vdd tlon tcl
[ak7864 a ] ms1336 - e - 00 10 20 12 / 01 5. pdn s witching characteristics (vdd=3.135~3.465v , ta=0 ? 70 ? c , unless otherwise specified ) ( note 1) please make pdn and en lo w when you turn on the power supply. ( note 2) led (cont_r/g/b control) lighting after max.1ms after en rise to high . 6. power down characteristic (vdd=3.1 35~3.465v , ta=0 ~ 70 ? c, unless otherwise specified ) item min. typ. max. unit. remarks supply current at power down 20 ? item symbol pin min. typ. max. unit conditions power down period 1 tpd1 pdn 150 ns powe r down period 2 tpd2 pdn 150 ns start up time tstup en 1 ms pdn vdd t pd2 3.135 v en t pd1 t stup
[ak7864 a ] ms1336 - e - 00 11 20 12 / 01 external circuit example cp cn led_b cont_r cont_g vss iref vdd en pdn ak7864 a led_r cpout vss vss led_g cont_b top view 13 14 15 16 1 2 3 4 5 6 7 8 9 10 11 12 1 f 1 f 10 f 4.7k ?
[ak7864 a ] ms1336 - e - 00 12 20 12 / 01 package 1. package dimension unit [mm] 2. marking marketing code 7864 - a date code xxxxx a detail of a 7864 - a xxx xx 3.000.07 3 . 0 0 0 . 0 7 a 9 13 16 1 5 8 12 c0.30 1 . 5 0 1.80 1 . 8 0 1.50 s 0.50 0 . 0 5 m a x 4 b 0 . 3 0 0 . 0 7 0.220.05 0.05 s a b m 0 . 7 0 s 0.05 0 . 0 0 0 . 0 5 0.17 0.27 0 . 1 2 0 . 1 8 a? a 0 . 7 5 m a x
[ak7864 a ] ms1336 - e - 00 13 20 12 / 01 important notice ? these products and their specifications are subject to change without notice. when you consider any use or application of these products, please make inqu iries the sales office of asahi kasei microdevices corporation (akm) or authorized distributors as to current status of the products. ? akm assumes no liability for infringement of any patent, intellectual property, or other rights in the application or use of any information contained herein. ? any export of these products, or devices or systems containing them, may require an export license or other official approval under the law and regulations of the country of export pertaining to customs and tariffs, cur rency exchange, or strategic materials. ? akm products are neither intended nor authorized for use as critical components note1) in any safety, life support, or other hazard related device or system note2) , and akm assumes no responsibility for such use, excep t for the use approved with the express written consent by representative director of akm. as used here: note1) a critical component is one whose failure to function or perform may reasonably be expected to result, whether directly or indirectly, in the lo ss of the safety or effectiveness of the device or system containing it, and which must therefore meet very high standards of performance and reliability. note2) a hazard related device or system is one designed or intended for life support or maintenance of safety or for applications in medicine, aerospace, nuclear energy, or other fields, in which its failure to function or perform may reasonably be expected to result in loss of life or in significant injury or damage to person or property. ? it is the resp onsibility of the buyer or distributor of akm products, who distributes, disposes of, or otherwise places the product with a third party, to notify such third party in advance of the above content and conditions, and the buyer or distributor agrees to assu me any and all responsibility and liability for and hold akm harmless from any and all claims arising from the use of said product in the absence of such notification.

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