1 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation features led drivers for parallel connected leds ultra low dropout voltage of 150mv (sp7614/14a) no emi, no switching noise integrated current matching pwm and analog brightness control enable/shutdown control shutdown current < 1 a small footprint sc-70 package low dropout led driver for any color led applications next generation mobile phones pda, dsc, mp3 players handheld computers lcd display modules keyboard backlight led displays typical application schematic the sp761x driver family provides a simple solution for a matched current source any color led. the current in the leds can be programmed by an external resistor. the individual led currents are 200 x iset, where iset is the current through the external resistor connected to the ctrl pin. the sp7611a is capable of driving four leds, while the sp7612/12a can drive three leds. the sp7614/14a is designated to drive two high current leds. led1 should always be connected to an led in order to have the other leds driven with a matched current to led1. the sp7612 /12a and sp7614/14a have enable pins. when these devices are disabled, the supply current drops to 0.01 a typical. the sp761x driver family is available in a small footprint 6-pin sc-70 package. preliminary sp7611a, sp7612/12a, sp7614/14a sp7614/14a 6 pin sc70 1 ctrl 3 n/c 4 gnd 2 led1 6 on/off 5 led2 now available in lead free packaging description v in led1 led2 gnd ctrl on/off enable v control r set sp7614/14a i set p/n channels steady state current per led sp7611a 4 40ma sp7612/12a 3 40ma sp7614/14a 2 80ma
2 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation these are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. exposure to absolute maximum rating conditions for extended periods of time may affect reliability. absolute maximum ratings electrical characteristics specifications are at t a =25 c, v in = 3.3 to 5.5, enable =v in , ? ? ? ? ? denotes the specifications which apply over the full operating temperature range, unless otherwise specified. v led1 , v led2 , v led3, v led4 and en voltage to gnd......................................................................................-0.3v to 6v ctrl voltage to gnd . ........................................................................................................ .................................0.5v output current (i out ) .............................................................................................................................. ...............40ma power dissipation per package - 6-pin sc-70 at t a =85 c...............................................................................190mw junction temperature........................................................................................................... ..............................+150 c storage temperature............................................................................................................ .............. -55 c to +150 c esd level. ............................................................................................................................... ....................................................................... 4kv hbm esd level. ............................................................................................................................... ....................................................................... 1kv cdm note 1: output current multiplication ratio (i led /i set ) is not linear. for actual ratio and i led please refer to typical performance characteristics @ page 4 and page 5. note 2: enable "on" is v on/off where i led1 > 20ma @ v led1 = 0.3v. enable "off" is v on/off where i led1 < 1 a @ v led1 > 0.3v. r e t e m a r a pn / p. n i m. p y t. x a ms t i n u e g a t l o v e d o h t a c d e la 1 1 6 7 p s a 2 1 / 2 1 6 7 p s 3 . 0 5 . 01v a 4 1 / 4 1 6 7 p s5 1 . 0 e r u t a r e p m e t t n e i b m a 0 4 -0 25 8c r e t e m a r a pn / p. n i m. p y t. x a ms t i n us n o i t i d n o c n o i t a c i l p i t l u m t n e r r u c t u p t u o ) 1 e t o n ( o i t a r a 1 1 6 7 p s a 2 1 / 2 1 6 7 p s 0 4 10 0 20 6 2 i t e s a 0 0 1 = v d e l v m 0 0 3 = a 4 1 / 4 1 6 7 p si t e s a 0 0 1 = v d e l v m 0 5 1 = i t n e r r u c d e l d e l ) e d o i d r e p (a 1 1 6 7 p s a 2 1 / 2 1 6 7 p s 0 2a m i t e s a 0 0 1 = v d e l v m 0 0 3 = a 4 1 / 4 1 6 7 p si t e s a 0 0 1 = v d e l v m 0 5 1 = n o i t a c i l p i t l u m t n e r r u c t u p t u o n o i t a r u t a s n i o i t a r a 2 1 / a 1 1 6 7 p s 5 6 35 3 45 0 5 i t e s a 5 2 = v d e l v 5 . = a 4 1 6 7 p s0 3 70 7 80 1 0 1 g n i h c t a m t n e r r u c d e l o t d e l3 -8 . 03% ? d a o l o n y c n e i c i f f e k a e p0 9% ? v n i v 3 = e d o m f f o n i t n e r r u c1 0 . 01a ? v n e v 0 = " e g a t l o v n o " e l b a n e . n i m ) 2 e t o n ( a 2 1 / 2 1 6 7 p s a 4 1 / 4 1 6 7 p s 3v ? i t e s a 0 5 1 = " e g a t l o v f f o " e l b a n e . x a m ) 2 e t o n ( a 2 1 / 2 1 6 7 p s a 4 1 / 4 1 6 7 p s 5 . 0v ?
3 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation pin description pinout sp7614/14a 6 pin sc70 1 ctrl 3 n/c 4 gnd 2 led1 6 on/off 5 led2 sp7612/12a 6 pin sc70 1 ctrl 3 led1 4 gnd 2 led2 6 on/off 5 led3 sp7611a 6 pin sc70 1 ctrl 3 led1 4 gnd 2 led2 6 led3 5 led4 . o n n i p e m a n n i p n o i t p i r c s e d a 1 1 6 7 p sa 2 1 / 2 1 6 7 p sa 4 1 / 4 1 6 7 p s 1l r t cl r t cl r t ct n e r r u c d e l s t e s 22 d e l2 d e l1 d e ld e l f o e d o h t a c o t t c e n n o c 31 d e l1 d e lc nd e l f o e d o h t a c o t t c e n n o c 4d n gd n gd n gd n u o r g 54 d e l3 d e l2 d e ld e l f o e d o h t a c o t t c e n n o c 6 3 d e ld e l f o e d o h t a c o t t c e n n o c f f o / n of f o / n oe l b a s i d / f f o / n o p i h c e c i v e dn w o d t u h st n e r r u c d e l 4 1 6 7 p s / 2 1 6 7 p se v i t c a n d h s 1 d e l r o , n i p n e e h t y b d e l l o r t n o c s i e d o m n w o d t u h s n i t n e r r u c d e l e h t . s 5 . 0 y l l a c i p y t s i e m i t l l a f t n e r r u c d e l . e g a t l o v e d o h t a c a 4 1 6 7 p s / a 2 1 6 7 p se v i s s a p n d h s , n i p n e e h t y b d e l l o r t n o c y l n o s i e d o m n w o d t u h s n i t n e r r u c d e l e h t s i e m i t l l a f t n e r r u c d e l . e g a t l o v e d o h t a c 1 d e l f o t n e d n e p e d n i s i d n a . s 5 . 1 y l l a c i p y t
4 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation sp7614 typical performance characteristics t t [] t ctrl voltage led current (1v/div) (20ma/div) time (1 s/div) enable voltage transient response control voltage transient response sp7614 led current versus enable voltage 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 ven voltage (v) led current (ma) sp7614 iled vs set resistor and cathode voltage (vcontrol = 3v) 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 10 20 30 40 50 60 70 80 90 100 set resistor (kohms) led current (ma) v k=50mv vk=100mv vk=150mv vk=200mv vk=250mv v k=300mv t t [] t time (1 s/div) enable voltage led current (1v/div) (20ma/div) sp7614 led current vs. led cathode voltage 5 10 15 20 25 30 35 00.20.40 .6 0.8 1 led cathode voltage (v) led current (ma) for iset = 25ua for iset = 50ua sp7614 led current vs temperature iset = 100ua, vcathode = 150mv 0 5 10 15 20 25 30 -40 -15 10 35 60 85 temperature (c) led current (ma) sp7614 iset versus ctrl voltage - vcathode=1v 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 ctrl pin voltage (v) set current (a)
5 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation sp7614a typical performance characteristics enable voltage transient response control voltage transient response t t [] t time (1 s/div) ctrl voltage led current (1v/div) (20ma/div) enable voltage (2v/div) t t [] t time (1 s/div) led voltage led current (1v/div) (20ma/div) ctrl voltage (2v/div) sp7614a led current versus enable voltage, vk=150mv -1.0 1.0 3.0 5.0 7.0 9.0 11.0 13.0 15.0 17.0 19.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 ven voltage (v) led current (ma) 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 ictrl (ua) iled (ma) ictrl (ua) sp7614a led current versus led cathode voltage 0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 cathode voltage (v) led current (ma) iset=25ua iset=50ua sp7614a iled vs set resistor and cathode voltage - v control =3v 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 10 20 30 40 50 60 70 80 90 100 set resistor (k ohms) led current (ma) v k=50mv v k=100mv v k=150mv v k=200mv v k=250mv v k=300mv sp7614a ctrl current versus ctrl voltage (vcontrol = open) 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 ctrl pin voltage (v) set current (a) iset (ua)
6 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation application information setting the led current the current flowing into leds is approximately 200 times greater than the current i set . the led current is controlled by i control and r set according to the follow- ing formula : i led = 200 x (v control - v ctrl ) / r set for v control = 3v and a specified led current, the r set value can be evaluated using the diagram shown in the typical performance characteristics section. for any other option, i set vs. v ctrl. the led's brightness can also be adjusted by driving enable or the ctrl pin with a pwm signal. the driving signal frequency should be greater than 100hz to avoid flickering, increasing to more than 1mhz, if necessary. leds are very sensitive to temperature. in most cases the maximum allowed junction temperature is 100?. the over temperature due to power dissipation is de- scribed by the following: t j = t a + ja x i xv f where t j is the led junction temperature, t a is the ambient temperature, ja is the junction to ambient thermal resistance, i is the led current and v f is the led forward voltage . when the temperature rises and the cathode voltage increases, sp761x reduces the current through leds. refer to "led current vs. led cathode voltage" graph under the typical performance characteristics section. the sp761x driver's low dropout architecture can sig- nificantly improve the efficiency compared to using simple ballast resistors. the system efficiency, defined as the ratio between the leds power and the input supplied power can be calculated as follows: efficiency = (v in - v cathode ) / v in the lower the v cathode , the higher the system effi- ciency. efficiency can be further improved using a higher v in with more leds as shown in example 3. application notes the ultra-low voltage drop across the sp761x series of led drivers, allows the devices to drive white, blue, and other color leds in a wide range of input voltages. the driver can be used in many applications. any of the sp761x series of led drivers can be used in the applications presented in this document, due to their similar operation. example 1: drive low v f white or blue leds directly from single cell li-ion when using white or blue low v f leds, and utilizing the drivers low voltage drop, only 3.4v in v in is needed for the full 20ma led current. at 3.1v, there is still 5ma typical current available for the leds. the single cell li- ion is utilized in most applications like cell phones or digital still cameras. in most cases, the li-ion battery voltage level only goes down to 3.0v, and not down to the full discharge level (2.7v) before requesting the charger. - t drop < 0.3v - v f (at 20ma) < 3.1v (low v f ) - v in (at 20ma) < - v drop +v f = 3.4v - v in (at 5ma typical) ~ 3.1v key advantages 1) no boost circuit needed for the lcd or keyboard backlight 2) drivers directly connected to a li-ion battery 3) no emi, no switching noise, no boost efficiency lost, no capacitor, and no inductor v in led1 gnd ctrl v control r set i set led3 led2 led4 sp7611a
7 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation example 2: drive high v f white or blue leds from existing bus from 4.0v to 5.5v high v f leds have a forward voltage drop in the range of 3.2v to 4.0v. in order to drive these leds with the maximum current of 20ma enabling maximum bright- ness, usually requires a boost circuit for a single cell li- ion power supply. the ultra-low voltage drop of the sp761x series is capable of driving high v f white or blue leds with its ultra-low dropout feature. the v in needs to be only 300mv higher than the highest v f in the circuit. application information - t drop < 0.3v - v f (at 20ma) < 3.3v to 4.0v (high v f ) - v in (at 20ma) = v drop +v f = 3.6v to 4.3v - v in (at 5ma typical) ~ 3.3v where v in = existing bus = 3.3v to 4.3v key advantages 1) no boost circuit needed for the lcd or keyboard backlight 2) drivers utilizes existing bus 3) ultra-low voltage drop provides the full 20ma led current at the lowest possible voltage level. example 3: drive white, blue red, amber leds string in a boost circuit, or existing voltage bus, the sp761x series of led drivers can be used to drive a whole string of leds and flexible brightness control - analog and/or pwm. - v drop < 0.3v - v in_min = n x v f + v drop - v in_min = n x v f + 5.5v where v in = existing bus, boost voltage key advantages 1) no need for current matching resistors and discrete transistors for brightness control. led brightness control the sp761x led drivers feature analog and pwm controls to give designers flexible brightness control. to determine the value of r set , use the "i set vs. v crtl " graph under the typical performance characteristics. 1. sp7611a - analog set v control and r set for led current i led = 200 x (v control - v cntr ) / r set - pwm v control = pwm -amplitude sets maximum led current -pulse width controls between 0 and maximum 2. sp7612 v in led1 gnd ctrl on/off enable v control r set sp7612/12a i set led3 led4 v in led1 gnd ctrl v control r set i set led3 led2 led4 sp7611a v in led1 gnd ctrl v control r set sp7611a i set led2 led4 ??umber of leds per branch led3 v in led1 gnd ctrl v control r set i set led3 led2 led4 sp7611a 3v
8 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation application information - analog set v control and r set for led current -i led = 200 x (v control - v ctrl ) / r set -amplitude sets maximum led current -pulse width controls between 0 and maximum - pwm -2 - pwm -1 set v control and r set for led current i led ~ 200 x i set on/off = pwm -amplitude has no effect on current -pulse width controls between 0 and maximum - analog set v control and r set for led current i led = 200 x (v control - v ctrl ) / r set - pwm - 1 -amplitude sets maximum led current -pulse width controls between 0 and maximum - pwm - 2 set v control and r set for led current i led ~ 200 x i set on/off = pwm -amplitude has no effect on current -pulse width controls between 0 and maximum 3. sp7614 v in led1 led2 v ss ctrl on/off enable v control r set sp7614/14a i set
9 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation package: 6 pin sc-70 a a2 a1 side view d e e/2 e1 n/2 2 1 b e e1 e1/2 n n/2 +1 l1 l 4x 1 seating plane gauge plane view c see view c h b b c with plating base metal b 1 index area (d/2 x e1/2) l2 - - 1.10 0 - 0.10 dimensions in (mm) 6 pin sc-70 jedec mo-203 (ab) variation 0.70 0.90 1.00 0.15 - 0.30 0.08 - 0.22 2.00 bsc 2.10 bsc 1.25 bsc 0.26 0.36 0.46 0.42 ref 0? 4? 8 a a1 a2 b c d e e1 l l1 l2 4? - 12 1 min nom max 0.15 bsc 6 pin sc-70
10 date: 10/11/04 sp7611a/7612/7614 low dropout led driver for any color led ?copyright 2004 sipex corporation corporation analog excellence sipex corporation reserves the right to make changes to any products described herein. sipex does not assume any liability aris ing out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor t he rights of others. sipex corporation headquarters and sales office 233 south hillview drive milpitas, ca 95035 tel: (408) 934-7500 fax: (408) 935-7600 ordering information part number temperature range package type sp7611aec6 .............................................. -40 c to +85 c ......................................................... 6 pin sc-70 sp7611aec6/tr ........................................ -40 c to +85 c ......................................................... 6 pin sc-70 sp7612ec6 ................................................ -40 c to +85 c ......................................................... 6 pin sc-70 sp7612ec6/tr .......................................... -40 c to +85 c ......................................................... 6 pin sc-70 sp7612aec6 .............................................. -40 c to +85 c ......................................................... 6 pin sc-70 sp7612aec6/tr ........................................ -40 c to +85 c ......................................................... 6 pin sc-70 sp7614ec6 ................................................ -40 c to +85 c ......................................................... 6 pin sc-70 sp7614ec6/tr .......................................... -40 c to +85 c ......................................................... 6 pin sc-70 sp7614aec6 .............................................. -40 c to +85 c ......................................................... 6 pin sc-70 sp7614aec6/tr ........................................ -40 c to +85 c ......................................................... 6 pin sc-70 /tr = tape and reel pack quantity is 2500 for sc70. available in lead free packaging. to order add "-l" suffix to part number. example: sp7614ec6/tr = standard; sp7614ec6-l/tr = lead free
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