AP8804 AP8804 document number: ds32050 rev. 2 - 5 1 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated low voltage pulsed led driver description the AP8804 is a low voltage linear led driver capable of operating from supplies as low as 1.8v. the AP8804 has an output curr ent tolerance of 10% at 25c at 250ma and 15% at the full rated current of 350ma. the maximum output saturation voltage at the full rated current is 200mv. pin assignments features ? 100mv maximum output saturation voltage ? tdfn small outline package ? 10% output current tolerance ? 0 to 70c junction temperature range ? available in ?green? molding compound (no br, sb) with lead free finish/rohs compliant (note1) typical application circuit notes: 1. eu directive 2002/95/ec (rohs). all applicable rohs exemptions applied, see eu directive 2002/95/ec annex notes . top vie w tdfn2020-6 3 2 1 4 6 out 5 nc v cc nc gnd bias ? 1000:1 ? current ? gain ? block ? linear ?? controller ? ? ? out ? ? i = 1000 i bias ? ? = 1000/r bias ? ? r bias 6v ? ~ ? 2v ? 6v ? ~ ? 0.1v ? 1000:1 current ? gain block ? linear ? controller ? bias v cc ? ? gnd ? 1.0v ? i out ? ?? ? 6v ~ ? 1.8v 6v ? ~ ? 0.1v ?
AP8804 AP8804 document number: ds32050 rev. 2 - 5 2 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated absolute maximum ratings symbol paramete r rating unit v cc supply voltage -0.3 to +8 (relative to gnd) v v out output voltage v bias bias input voltage -0.3 to +0.3 (relative to gnd) v t j junction temperature 150 c t st storage temperature -65 to +150 c note: these are stress ratings only. operation outside the ab solute maximum ratings may cause device failure. operation at the absolute maximum rating for extended periods may reduce device reliability. semiconductor devices are esd sensitive and may be damaged by exposure to esd events. suitable esd precautions sh ould be taken when handling and transporting these devices. recommended operating conditions symbol paramete r min max unit v cc supply voltage 1.8 6 v i bias bias input current -0.33 0 ma i o output current 50 350 ma t a operating ambient temper ature range 0 70 c package thermal data thermal resistance package unit junction-to-ambient, ja tdfn2020-6 80 c/w junction-to-case, jc tdfn2020-6 20 electrical characteristics (under operating conditions) v out = 0.2v, t a = 25c (unless otherwise stated). all typical are at 25c (ft = 0 to 70c) parameter conditions t a min typ. max unit dc parameters bias voltage v cc = 1.8v, r bias = 3.05k ? 2 25 900 1040 1200 mv ft 860 1240 output current accuracy 3 v cc = 2.0v to 6v, v out = v cc ? 1.8v, r bias = 4.1k ? 25 225 250 275 ma saturated output current tolerance 5 v cc = 2.0v, v out = 0.2v r bias = 3.05k ? , i out = 350ma 25 15 % ft 20 v cc = 2.0v, v out = 0.5v r bias = 3.05k ? i out = 350ma 25 10 % ft 15 v cc = 2.0v, v out = 0.15v r bias = 4.1k ? , i out = 250ma 25 15 % ft 20 current gain (i out /i bias ) 3, 4 v cc = 2v, v out = 0.2v, 50a < i bias < 350a 25 1000 quiescent current v cc = 6v, r bias = open circuit ft 100 150 a supply current (active) v cc = 2v, r bias = 3.05k ? , v out = 0.5v ft 5.5 9 ma output leakage (off) vcc = 6v, r bias >= 2m ? , v out = 6v 25 <1 10 ua output leakage (disabled) vcc = 0v, v out = 6v 25 <1 100 na ac parameters rise time (10% to 90%) 5 v cc = 2.0v, v out = 0.5v, r bias = o/c to 3.05k ? 0.2 s fall time (90% to 10%) 5 r bias = 3.05k ? to o/c 0.2 propagation delay(low to high) 5 v cc = 2.0v, v out = 0.5v, r bias = o/c to 3.05k ? 0.4 propagation delay(high to low) 5 r bias = 3.05k ? to o/c 0.2 notes: 2. r bias connected to gnd see figure 1 3. all active output current measurements are pulsed tests of 8us duration, 10% duty cycle 4. see typical characteristics for a graph of output current vs. r bias value 5. see figure 2
AP8804 AP8804 document number: ds32050 rev. 2 - 5 3 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated figure 1: application circuit figure 2: timing waveforms ? 1000:1 current gain block linear controller = 1000 i bias = 1000/r bias 6v ~ 2v 6v ~ 0.1v 1000:1 current gain block linear controller bias v cc out gnd 1.0v i out r bias 6v ~ 1.8v 6v ~ 0.1v ? 50% 90% 10% 50% i bias i out t pdlh t pdhl 50% 90% 10% 50% t f t r
AP8804 AP8804 document number: ds32050 rev. 2 - 5 4 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated typical characteristics 0 50 100 150 200 250 300 350 400 01 234 5 6 v (v) i vs. v cc out c c i (ma) out r_b= 20k r_ b= 9. 7k r_ b= 6. 8k r_ b= 4. 1k r_ b= 3. 0k v = v - 1.8v, t = 25 c, 8 puls e tes t 10% d uty cyc le out cc a s 0 50 100 150 200 250 300 350 400 0 5 10 15 20 25 r (k ohms) bi as i vs. r out b ia s i (ma) out v = 3v, v = v -v cc out c c led r_b = 4.1k 0 50 100 150 200 250 300 350 400 0 12 3 4 5 6 r_b = 3.0k v (v) i vs. v cc out cc i (ma) out r_b = 4.1k r_b = 6.8k r_b = 9.7k r_b = 20k v = v v, t 25c 8 s p ulse test @ 1 0% duty cyc le out cc led a 0 50 100 150 200 250 300 350 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 v (v) out i (ma) out i vs. v out cc r_b = 20k r_b = 9.7k r_b = 6.8k r_b = 4.1k r_b = 3.0k v = v +1. 8, t = 2 5 c, 8 s pu lsed test, 10% du ty cycle cc out a
AP8804 AP8804 document number: ds32050 rev. 2 - 5 5 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated typical characteristics (cont.) channel 1 (upper): v_bias @ 0.5v/div channel 2 (lower): i_out @ 100ma/div timebase: 2us/div pulse response r_bias 4.1k 0ma 0v 0v 0ma channel 1 (upper): v_bias @ 0.5v/div channel 2 (lower): i_out @ 20ma/div timebase: 2us/div pulse response r_bias 21.0k pin descriptions name i/o pin # function nc - 1 no connection. may be grounded or left floating. gnd power 2 gnd or the most negative termi nal of the led driver. also carries the led return current. bias i 3 the output of an internal voltage reference (1.0v approx.). connect a resistor r bias from this pin to the external control input. the led driver amplifies the r bias resistor current by a factor of nominally1000. open circuiting this pin or driving this pin to >1.25v will turn off the output of the AP8804. avoid unnecessary stray capacitance at this pin, and connect r bias as close as possible to it. v cc power 4 the supply input pin of the led driver. this pin supplies the internal circuitry of the ic which is typically 80ua + 2.5% of the led out put current. it is advisable to decouple this pin with a 100nf capacitor to gnd. nc - 5 no connection. may be grounded or left floating. out o 6 the output of the led driver, normally c onnected to the cat hode of the led. the normal working range of this pin is 0.1v (0.1v above gnd pin potential) to 6v. it is permissible for the voltage on this pin to be higher than v cc .
AP8804 AP8804 document number: ds32050 rev. 2 - 5 6 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated applications information setting the output current the AP8804 is controlled by an input current at the bias pin. when an led or load re sistance is connected between a positive supply and out, the load current i out is proportional to the input current at t he bias input of the AP8804. the current gain, a i is nominally -1000. the voltage at the bias pin is controlled to nominally +1.0v. the resistor r bias sets the input current according to the input voltage, v in , as in figure 3. figure 3 therefore the input voltage, v in , determines the output current according to this equation: i out = a i * (v in ? v bias ) / r bias if v in v bias and i out = 0 if v in v bias note that these equations are approxim ate and a more accurate value of curr ent can be found using the graph of i out vs r bias . select r bias to give the required i out . for example, if r bias = 3k, an input of 0v will give an output current of nominally 350ma, while an input of about +1.1v or greater will give an output current equal to the leakage value which is typically less than1a. driving the AP8804 the input current is approximately 1/r bias when the driven end of r bias is pulled to 0v or roughly output current divided by 1000. for a typical output current of up to about 300 ma, the input current will be 300a or less. hence a low level cmos or open-dra in logic drive level is convenient to turn the led on (l ogic low, 0v) and off (logic high, 1v or greater). by connecting a switch to ground in series with r bias (see figure 3) the device can be turned on and off. typical applications for this include led dimming as well as data interface applications. an alternate way of turning the output of the AP8804 off is to dr ive the bias pin to greater than 1.1v. however direct drive t o this pin is not recommended. stray capa citance at the bias pin must be avoi ded for stability and the resistor r bias should be placed close to the bias pin. the best method is to drive the input through the series resistor r bias as shown from a cmos or open drain logic signal. vcc pin quiescent current is typically 100ua and out pin leakage is typically less than 1ua when the device is turned off using the bias pin. bias pin controlled output switching times are less than 1us. a further means of disabling the device is to turn off the supply to the vcc pin. in this state, assuming the led anode is sti ll connected to the supply, the vcc pin current is of course zero and the out pin leakage is typically less than 1na. this method has the advantage of reducing the quiescent current from about 100a to less than 1na. when using this switching method, the time to settle to the desired current level may be several microseconds. 1000:1 current gain block linear controller bias v cc out gnd 1.25v i out = 1000 i bias = 1000/r bias r bias 6v ~ 2v 6v ~ 0.1v 1000:1 current gain block linear controller bias v cc out gnd 1.0v i out = 1000 i bias bias r bias 6v ~ 1.8v 6v ~ 0.1v vin
AP8804 AP8804 document number: ds32050 rev. 2 - 5 7 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated pcb layout and supply conditioning for a satisfactory pulse shape and ac stability, attention shou ld be given to power supply decoupling. connect a 0.1f to 1f x7r ceramic capacitor from vcc to the common ground plane clos e to the vcc pin. position the capacitor close to the v cc pin and use local vias to ground the capacitor. additional ground vias should be placed as close as possible to the central paddle connection for the sake of both the pulse performance and therma l heat-sinking. the ground plane is also required to minimize undesired common-impedance coupling between input and output. excessive stray capacitance at the bias pin affects stability. it is sufficient to pl ace the input bias resistor close to the bias pin to minimize the pcb trace capacitance to ground. the AP8804 has been designed to drive the cathode of a low voltage led which has the anode connected to the same node as v cc pin. alternatively the anode may be connected to a higher voltage than v cc within the limits given. however best led current regulation will be obtained when the anode is connected to v cc . power dissipation and operating temperature although the performance of the AP8804 is not significantly affected by junction tem perature, excessive power dissipation does affect the target output current. the typi cal variation of i_out with power dissipation is approximately +0.065%/mw. a typica l remote control application uses an nec protoc ol data-burst with a low impedance 3v supply and 1.6v drop (at 250ma) across the led load. under these conditions, the po wer dissipation related error in i_out will be approximately 3% average during the bur st. ordering information device package code packaging 7?/13? tape and reel quantity part number suffix AP8804sng-7 sn dfn2020-6 3000/ tape & reel -7 marking information a 7 = product type marking code y = year 0 ~ 9 w = week: a ~ z : 1 ~ 26 week; a ~ z : 27 ~ 52 week; z represents 52 and 53 week a 7 y w x
AP8804 AP8804 document number: ds32050 rev. 2 - 5 8 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated package outline dimensions suggested pad layout dfn2020-6 dim min max typ a 0.57 0.63 0.60 a1 0 0.05 0.03 a3 ? ? 0.15 b 0.20 0.30 0.25 d 1.95 2.075 2.00 d2 1.45 1.65 1.55 e ? ? 0.65 e 1.95 2.075 2.00 e2 0.76 0.96 0.86 l 0.30 0.40 0.35 all dimensions in mm dimensions value (in mm) z 1.67 g 0.15 x1 0.90 x2 0.45 y 0.37 c 0.65 seating plane d2 d e pin#1 id l b d2/2 e2 e a1 a a3 g g yc z y x2 x1
AP8804 AP8804 document number: ds32050 rev. 2 - 5 9 of 9 www.diodes.com february 2010 ? diodes incorporated confidential a product line o f diodes incorporated important notice diodes incorporated makes no warranty of any kind, express or implied, with regards to this document, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose (and their equivalents under the laws of any jurisdiction). diodes incorporated and its subsidiaries reserve the right to ma ke modifications, enhancements, im provements, corrections or ot her changes without further notice to this document and any product described herein. diodes incorporated does not assume any liability ari sing out of the application or use of this document or any product described her ein; neither does diodes inco rporated convey any license under its patent or trademark rights, nor the rights of others. any customer or us er of this document or products described herein in such applica tions shall assume all risks of such use and will agree to hold diodes incorporat ed and all the companies whose products are represented on diodes incorporated website, harmless against all damages. diodes incorporated does not warrant or accept any liability what soever in respect of any pr oducts purchased through unauthoriz ed sales channel. should customers purchase or use diodes in corporated products for any unintended or unauthorized application, customers shall i ndemnify and hold diodes incorporated and its repres entatives harmless against all claims, dam ages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application. products described herein may be covered by one or more united states, international or foreign patents pending. product names and markings noted herein may also be covered by one or more united states, international or foreign trademarks. life support diodes incorporated products are specifically not authorized for use as critical co mponents in life support devices or systems without the express written approval of the chief executive offi cer of diodes incorporated. as used herein: a. life support devices or syst ems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when prope rly used in accordance with inst ructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. b. a critical component is any component in a life support dev ice or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. customers represent that they have all necessary expertise in the safety and regulatory ramifi cations of their life support dev ices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning the ir products and any use of diodes incorporated products in such safety-critica l, life support devices or systems, notwithstanding any devices- or systems-related information or support that may be provided by diodes incorporated. further, customers must fully indemnify diodes incorporate d and its representatives against any damages arising out of the use of diodes incorporat ed products in such safety-critical, life support devices or systems. copyright ? 2010, diodes incorporated www.diodes.com
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