aat3123/23a/24 data sheet - Skyworks Solutions, Inc.
Contents
1. rA VIN C1 C1 TIF VOUT C1 C2 VeATTERY Gn Cour AAT3124 C2 HE 1uF 1uF 1uF C2 _1 o b D1 D2 D4 EN SET gt EN SET D5 D6 GND wRED1 wRED2 GRN1 wGRN2 wBLU1 wBLU2 Ne o o Enable Red z nable gt KH Me Enable Green H m Me Enable Blue gt im AAT3124 Separately Driving RGB Color LEDs D VIN C1 C1 T 1pF VOUT C1 C2 VeaTTERY Gin Cour AAT3124 C2 Th 1uF 1uF 1uF C2 o c D1 aoe D2 D3 Common Anode D4 RGB Color LED EN SET gt J EN SET D5 D6 GND y RED y GRN y BLU ral Lt Enable Red gt i a Enable Green H z Enable Blue gt m a aS AAT3124 Driving Common Anode RGB Color LED Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 15 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Ordering Information Package Marking Part Number Tape and Reel Description TSOPJW 12 AAT31231TP 20 T1 4 Channel Output TSOPIW 12 AAT3123AITP 20 T1 4 Channel Output with Increased Start Up Current see Test Current Channel Disable section on page 11 QFN44 16 AAT31241 SN 20 T1 6 Channel Output T2. INIA nm A U N Pin Configuration TSOP W 12 QFN44 16 TSOP W 14 Top View Top View Top View m zZ on Zz o m 34 20 Cet as 2 C2 of e RF e 2 13 OUT 2 1 GND D2 m O 72 GND D1 3 z D4 C1 3 aaT3123 0 IN a i C1 4 AAT3123A 0 EN SET D5 E 7 C2 EN SET 4_ AAT3124 n C1 D4 C3 D1 z l IN Cs e C1 D3 7 D2 Pe peut GND gt 2 OUT D3 Ha Sesser ss WOUT C2 L2 8 C2 oaz w O Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Absolute Maximum Ratings Description Input Voltage 0 3 to 6 Vout Charge Pump Output 0 3 to 6 FB Ven set FB or EN SET to GND Voltage 0 3 to 6 Ven SeT MAx Maximum EN SET to Input Voltage 0 3 Tour Maximum DC Output Current 150 T Operating Junction Temperature Range 40 to 150 Thermal I nformation Symbol Description
3. D1 Pay VER D2 Ei D3 Display Module D4 amp EN SET gt EN SET D1 D2 D3 D4 ene Na Na Na Rat Rez Res Rea l GE S Resistor R is optional AAT3123 23A Driving a Display Module with Four Paralleled White LEDs VIN C1 ie D1 D2 D3 D4 VOUT c1 Na C2 C Cour Rei Rez Regs Rea VBATTERY AAT3124 i 1uF 1uF 1uF i C2 Resistor R is optional o ____e____ _ D1 i D2 D3 D4 EN SET gt j EN SET D5 if D5 wv D6 D6 Ne GND Ne Ne Res Reo AAT3124 Driving Two Groups of Paralleled White LEDs e g Skyworks Solutions Inc e Phone 781 376 3000 e Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com Resistor R is optional main and sub LCD backlights 13 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Additional Application Circuits continued B VIN C1 2 gt C1 1uF VOUT c1 C2 VBATTERY On Cour AAT3124 C2 Te 1uF 1uF 1uF C2 L hd D1 2S D2 D4 D1 D2 D3 D4 D5 y D6 EN SET gt G EN SET D5 Ne Na Na N D6 GND Rg Re2 Rg3 Rg4 Res R
4. QFN44 16 TSOPJW 12 QFN44 164 TSOPJW 125 Thermal Resistance Maximum Power Dissipation 1 Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device Functional operation at conditions other than the operating conditions specified is not implied Only one Absolute Maximum Rating should be applied at any one time Based on long term current density limitation Mounted on an FR4 board Derate 20mW C above 25 C Derate 6 25mW C above 25 C AUN Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Electrical Characteristics Cin Cour Ci Co 1 0UF Ta 40 C to 85 C unless otherwise noted Typical values are Ta 25 C Vin 3 5V Symbol Description Conditions Min Typ Max Units Input Power Supply Vin Operation Range Tec Operating Current 3 0 lt Vm lt 5 5 Active No Load Current Isonna Shutdown Current EN 0 Tpx Output Current Vin 3 5V Code 32 Ta 25 C VD1 D4 3 6V Viy 3 5V VD5 VD6 3 6V Vn 3 5V Vin 3 5V Tout toraL 120mA Measured from IN to OUT I p match Current Matching Between Any T
5. Voiope 3 4V 80 75 70 65 60 27 29 31 33 35 37 39 41 43 45 47 49 5 1 Input Voltage V Quiescent Current vs Input Voltage a Vpiove 3 4V 0 6 L Voon 3 0V Voiove 3 2V 27 29 31 33 35 37 39 41 43 45 47 49 5 1 Input Voltage V Ipiope MA 0 850 0 825 0 800 0 775 0 750 0 725 0 700 0 675 0 650 0 625 0 600 Efficiency 25 C Efficiency vs Input Voltage 4x10mA 100 95 90 Voiove 3 2V Vpione 3 4V 85 80 75 70 65 60 55 50 Voiope 3 0V 27 29 31 33 35 3 7 39 41 43 45 47 49 5 1 Input Voltage V Ibiope VS Input Voltage 4x10mA 45 Voiope 3 2V Voione 3 4V i iia ae Vpiope 3 0V 35 27 29 31 33 35 3 7 39 41 43 45 47 49 51 Input Voltage V Vin and V vs Vin Vin _ Viv 2 5 3 0 3 5 4 0 45 5 0 5 5 Input Voltage V Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 Typical High Efficiency X 1 5X Frac
6. clock so 1dB of attenuation is achieved by clocking the EN SET pin 31 times The counter can be clocked at speeds up to 1MHz so intermediate states are not visible The first rising edge of EN SET enables the IC and ini tially sets the output LED current to 31dB the lowest setting equal to 525pA Once the final clock cycle is input for the desired brightness level the EN SET pin is held high to maintain the device output current at the pro grammed level The device is disabled 500us after the EN SET pin transitions to a logic low state The EN SET timing is designed to accommodate a wide range of data rates After the first rising edge of EN SET the charge pump is enabled and reaches full capacity after the soft start time tss During the soft start time multiple clock pulses may be entered on the EN SET pin to set the final output cur rent level with a single burst of clocks Alternatively the EN SET clock pulses may be entered one at a time to gradually increase LED brightness over any desired time period A constant current is sourced as long as EN SET remains in a logic high state The current source outputs are switched off after EN SET has remained in a low state for at least the tog timeout period LED Selection The AAT3123 23A 24 is specifically intended for driving white LEDs However the device design will allow the AAT3123 23A 24 to drive most types of LEDs with for ward voltage specifications ranging from 2 0V to
7. 23A 24 contains a fractional charge pump which will boost the input supply voltage in the event where Vy is less than the voltage required on the con stant current source outputs The efficiency n can be simply defined as a linear voltage regulator with an effective output voltage that is equal to one and one half times the input voltage Efficiency n for an ideal 1 5X charge pump can typically be expressed as the output power divided by the input power In addition with an ideal 1 5X charge pump the output current may be expressed as 2 3 of the input current The expression to define the ideal efficiency n can be rewritten as Pour Vour lour Vour Pin Vin z 1 5lour 1 5Vin or Vout For a charge pump with an output of 5V and a nominal input of 3 5V the theoretical efficiency is 95 Due to internal switching losses and IC quiescent current con sumption the actual efficiency can be measured at 93 These figures are in close agreement for output load con ditions from 1mA to 100mA Efficiency will decrease as load current drops below 0 05mA or when the level of Vin approaches Vout Refer to the Typical Characteristics sec tion of this datasheet for measured plots of efficiency versus input voltage and output load current for the given charge pump output voltage options Capacitor Selection Careful selection of the four external capacitors Cy Ci Cz and Cour is important because they will affect
8. Ea biT 4 000 0 050 2 280 REF Top View Bottom View s l 3 i S Q a t 0 214 0 0364 S o Side View All dimensions in millimeters 1 The leadless package family which includes QFN TQFN DFN TDFN and STDFN has exposed copper unplated at the end of the lead terminals due to the manufacturing process A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 17 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications a es 4 0 45 0 15 0 05 0 04 4 gt 2 75 0 25 TSOP W 14 0 20 6 05 LJ LJ LI LI LJ LU ry Oo o ba i Oo o H 8 N N Y l l l l l i 1 Y 0 40 BSC Top View 0 04 REF 0 05 3 05 0 10 ja gt wo Q 85 sg F oo coo wo 8 8 e 4 44 Side View End View All dimensions in millimeters Copyright 2012 2013 Skyworks Solutions Inc All Rights Reserve
9. dently simultaneously or multiplexed to produce any variety of lighting effects By reprogramming the current source via the serial interface between switching tran sitions the brightness of individual LEDs or banks of LEDs can also be controlled Charge Pump Compatibility The four output AAT3123 is pin compatible with the AAT3113 in both QFN and TSOPJW packages The six output AAT3124 is pin compatible with the AAT3114 in the QFN package Compared to the AAT3113 14 the AAT3123 23A 24 offers an improved overall efficiency wider operating range and the ability to drive high V LEDs up to 4 3V at full current from a 3V input condi tion The AAT3123 23A 24 is well suited for battery powered applications using single cell lithium ion li ion batteries 4 2V to 2 8V lithium polymer batteries and 3 series connected dry cells 3 6V Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Additional Application Circuits rs VIN C1 C1 1uF VOUT C1 C2 VBATTERY Cin Cour AAT3123 C2 Jk tyr 14F AAT3123A T thr C2 b
10. turn on time output ripple and transient performance Optimum performance will be obtained when low equivalent series Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 10 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications resistance ESR ceramic capacitors are used In gener al low ESR may be defined as less than 100maQ A value of 1uF for all four capacitors is a good starting point when choosing capacitors If the LED current sources are only programmed for light current levels then the capacitor size may be decreased Capacitor Characteristics Ceramic composition capacitors are highly recommend ed over all other types of capacitors for use with the AAT3123 23A 24 Ceramic capacitors offer many advan tages over their tantalum and aluminum electrolytic counterparts A ceramic capacitor typically has very low ESR is lowest cost has a smaller PCB footprint and is non polarized Low ESR ceramic capacitors help to max imize charge pump transient response Since ceramic capacitors are non polarized they are not prone to incorrect connection damage Equivalent Series Resistance ESR is an important characteristic to consider when selecting a capacitor ESR is a
11. 4 3V EN SET Timing LED applications may include main and sub LCD display backlighting camera photo flash applications color RGB LEDs infrared IR diodes for remotes and other loads benefiting from a controlled output current gener ated from a varying input voltage Since the D1 to D6 output current sources are matched with negligible volt age dependence LED brightness will be matched regard less of the specific LED forward voltage Vp levels In some instances e g in high luminous output applica tions such as photo flash it may be necessary to drive high V type LEDs The low dropout current sources in the AAT3123 23A 24 make it capable of driving LEDs with forward voltages as high as 4 3V at full current from an input supply as low as 3 0V Outputs can be paralleled to drive high current LEDs without complication Device Switching Noise Performance The AAT3123 23A 24 operates at a fixed frequency of approximately 1MHz to control noise and limit harmonics that can interfere with the RF operation of cellular tele phone handsets or other communication devices Back injected noise appearing on the input pin of the charge pump is 20mV peak to peak typically ten times less than inductor based DC DC boost converter white LED back light solutions The AAT3123 23A 24 soft start feature prevents noise transient effects associated with inrush currents during start up of the charge pump circuit Power Efficiency an
12. AAT3123 23A 24 can changed succes sively to brighten or dim LEDs in smooth transitions e g to fade out or in abrupt steps giving the user complete programmability and real time control of LED brightness Table 1 Constant Current Source Output Programming Levels mA Normalized Output Current Settings 0 9 0 8 0 7 0 6 0 5 0 4 0 3 Normalized lour D1 to D6 0 2 0 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Code Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications EN SET Serial I nterface The current source output magnitude is controlled by the EN SET pin using Skyworks Simple Serial Control S Cwire interface The interface records rising edges of the EN SET pin and decodes them into 32 individual cur rent level settings each 1dB apart Code 32 is full scale and Code 1 is full scale attenuated by 31dB The modulo 32 interface wraps states back to State 1 after the 32nd
13. Efficiency X 1 5X Fractional Charge Pump for White LED Applications Functional Block Diagram VIN Soft Start Control 1MHz Oscillator Voltage Reference Current Reference S Cwire Interface 32 x 8 bit ROM Functional Description The AAT3123 23A 24 is a dual mode load switch 1X and high efficiency 1 5X fractional charge pump device intended for white LED backlight applications The frac tional charge pump consists of a low dropout linear volt age regulator followed by a 1 5X charge pump with multiple current source outputs To maximize power conversion efficiency an internal feedback control sens ing circuit monitors the voltage required on the constant current source outputs This control circuit then sets the load switch and charge pump functions based upon the input voltage level versus the output voltage level need ed This function significantly enhances overall device efficiency when the input voltage level is greater than the voltage required at the constant current source out puts For the AAT3123 23A the 1X load switch 1 5X charge pump mode is decided on the voltage sensed on the output D1 The AAT3124 bases the 1X load switch 1 5X charge pump mode decision on the voltage levels sensed on either the D1 D4 output group or the D5 D6 output group whichever is greater Switchover between the 1 5X charge pump operating mode and the 1X load switch mode occurs automatically as a function o
14. MED SKYWORKS DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION TEXT GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES IN CLUDING BUT NOT LIMITED TO ANY SPECIAL INDIRECT INCIDENTAL STATUTORY OR CONSEQUENTIAL DAMAGES INCLUDING WITHOUT LIMITATION LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM THE USE OF THE MATERIALS OR INFORMATION WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE Skyworks products are not intended for use in medical lifesaving or life sustaining applications or other equipment in which the failure of the Skyworks products could lead to personal injury death physical or en vironmental damage Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper use or sale Customers are responsible for their products and applications using Skyworks products which may deviate from published specifications as a result of design defects errors or operation of products outside of pub lished parameters or design specifications Customers should include design and operating safeguards to minimize these and other risks Skyworks assumes no liability for applications assistance customer product design or damage to any equipment resulting from the use of Skyworks products outside of stated published spe
15. SOPJW 14 AAT31241TO 20 T1 6 Channel Output D Skyworks Green products are compliant with all applicable legislation and are halogen free amp For additional information refer to Skyworks Definition of Green document number Q04 0074 Package Information TSOP W 12 2 40 0 10 2 85 0 20 1 1 i aa aa aa a gt 0 50 BSC 0 50 BSC 0 50 BSC 0 50 BSC 0 50 BSC 7 NOM 3 00 0 10 k s 3 e oy 8 Jeg o ep SS lt 4 N o g 2 _ _ 48 2 4 4 0 055 0 045 4 Eeng 0 45 0 15 2 75 0 25 All dimensions in millimeters 1 XYY assembly and date code 2 Sample stock is generally held on all part numbers listed in BOLD Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 16 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications QFN44 162 2 400 0 050 lt 0 330 0 075 Pin 1 Identification gt lt 16 Pin 1 Dot By Marking s f ja a C0 3 0 650 BSC 0 550 0 020 4 000 0 050 2 400 0 050
16. XxX SKYWORKS DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications General Description Features The AAT3123 23A 24 is a low noise constant frequency charge pump DC DC converter that uses a dual mode load switch 1X and fractional 1 5X conversion to maximize efficiency for white LED applications The device can be used to produce current levels up to 20mMA to drive up to six LEDs from a 2 7V to 5 5V input Outputs may be operated individually or paralleled for driving higher current LEDs A low external parts count two 1pF flying capacitors and two small 1uF capacitors at V n and OUT make the AAT3123 23A 24 ideally suited for small battery powered applications Skyworks Simple Serial Control S Cwire interface is used to enable disable and set the LED drive current with a 32 level logarithmic scale LED brightness control The AAT3123 23A 24 has a thermal management sys tem to protect the device in the event of a short circuit condition at the output pin Built in soft start circuitry prevents excessive inrush current during start up A high charge pump switching frequency enables the use of very small external capacitors A low current shutdown feature disconnects the load from Vin and reduces quies cent current to less than 1pA The device also integrates a test current auto disable feature for each channel The AAT3123 23A is available in a very small Pb fr
17. ast ing the programmed output current The test current in the AAT3123A is higher 150yHA to accommodate LEDs with lower impedance in failure mode Thermal Protection The AAT3123 23A 24 has a thermal protection circuit that will shut down the internal LDO and charge pump if the die temperature rises above the thermal limit as is the case during a short circuit of the OUT pin Driving Multiple LEDs White LED Display Module Backlights and Individual LEDs Connected in Parallel The AAT3123 23A 24 D1 to D6 outputs are true constant current sources capable of driving up to 20mA each over the operation input voltage range Since these outputs are true constant current sources they may be con nected in parallel to drive a single power output Any combination of outputs D1 to D6 may be connected in parallel The maximum total output current is a sum of how many current sources are parallel connected This feature is particularly useful to power pre manufactured display modules which are pre wired with white LED backlights connected in a parallel circuit configuration Any combination of outputs may be connected in parallel to drive groups of LEDs The AAT3123 internal current source reference circuit bases feedback from current sensed on the D1 output The AAT3124 internal current source reference circuit bases feedback from current sensed on the Di and D5 outputs For best operation the only requirement for this type of applicatio
18. cifications or parameters Skyworks the Skyworks symbol and Breakthrough Simplicity are trademarks or registered trademarks of Skyworks Solutions Inc in the United States and other countries Third party brands and names are for identification purposes only and are the property of their respective owners Additional information including relevant terms and conditions posted at www skyworksinc com are incorporated by reference Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 18 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013
19. d Information in this document is provided in connection with Skyworks Solutions Inc Skyworks products or services These materials including the information contained herein are provided by Skyworks as a service to its customers and may be used for informational purposes only by the customer Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein Sky works may change its documentation products services specifications or product descriptions at any time without notice Skyworks makes no commitment to update the materials or information and shall have no responsibility whatsoever for conflicts incompatibilities or other difficulties arising from any future changes No license whether express implied by estoppel or otherwise is granted to any intellectual property rights by this document Skyworks assumes no liability for any materials products or information provided here under including the sale distribution reproduction or use of Skyworks products information or materials except as may be provided in Skyworks Terms and Conditions of Sale THE MATERIALS PRODUCTS AND INFORMATION ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND WHETHER EXPRESS IMPLIED STATUTORY OR OTHERWISE INCLUDING FITNESS FOR A PARTICULAR PURPOSE OR USE MERCHANTABILITY PERFORMANCE QUALITY OR NON INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAI
20. d Device Evaluation The charge pump efficiency discussion in the following sections only accounts for efficiency of the charge pump section itself Due to the unique circuit architecture and design of the AAT3123 23A 24 it is very difficult to measure efficiency in terms of a percent value compar ing input power over output power HI e EN SET Code OFF X 1 Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Since the AAT3123 23A 24 outputs are pure constant current sources and typically drive individual loads it is difficult to measure the output voltage for a given output D1 to D6 to derive an overall output power measure ment For any given application white LED forward volt age levels can differ yet the output drive current will be maintained as a constant This makes quantifying output power a difficult task when taken in the context of comparing to other white LED driver circuit topologies A better way to quantify total device efficiency is to observe the total input power to the device for a given LED current drive level The best white LED driver for a given application shoul
21. d be based on trade offs of size external component count reliability operating range and total energy usage not just efficiency The AAT3123 23A 24 efficiency may be quantified under very specific conditions and is dependent upon the input voltage versus the output voltage seen across the loads applied to outputs D1 through D4 or D6 for a given con stant current setting Depending upon the case of Vin being greater than the specific voltage seen across the load on D1 or D5 when the AAT3124 is used the device will operate in load switch mode If the voltage seen on the constant current source output is less than V then the device will operate in 1 5X charge pump mode Each of these two modes will yield different efficiency values Refer to the following two sections for explanations of each operational mode Load Switch Mode Efficiency The AAT3123 23A 24 load switch mode is operational at all times and functions alone to enhance device power conversion efficiency when the condition exists where Vin is greater than voltage across the load connected to the constant current source outputs When in load switch mode the voltage conversion efficiency is defined as output power divided by input power Pout Py The expression to define the ideal efficiency n can be rewritten as Pour 2 Vout lour Vout 7 Pn Vin lout Vin or ER Vout n 100 Ve Charge Pump Section Efficiency The AAT3123
22. ee di kd Photo Flash LED D Resistor R is optional In some applications white LED forward voltages Vp can vary significantly Ballast resistors between the LED cathodes and ground are recommended for balancing the forward voltage differences The ballast resistor value may be approximated by the following equation Re Vsource Ve R E AAT3124 Driving a High Current Photo Flash LED d VIN C1 C1 1uF VOUT C1 C2 VeaTTERY Cn Cour AAT3124 C2 aya 1uF 1uF 1uF C2 oe D1 hg a D2 D3 e D4 y D1 D2 D3 D4 EN SET gt EN SET D5 o Ne Ne D GND y D5 y D6 Enable Display Backlight gt m Ke Enable Keyboard Backlight gt H H AAT3124 Driving Two Groups of Paralleled White LEDs with series N channel switch Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 14 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Additional Application Circuits continued
23. ee 12 pin TSOPJW package The six output AAT3124 is available in the Pb free 16 pin 4x4mm QFN and 14 pin TSOPJW packages Typical Application e Vin Range 2 7V to 5 5V e Dual Mode 1X and 1 5X Charge Pump for Maximum Efficiency e Drives Low V and High V Type LEDs e Up to Six 20mA Outputs AAT3124 e Up to Four 20mA Outputs AAT3123 23A e 32 Position Logarithmic Scale with Digital Control e Simple Serial Control S2Cwire Interface e Low Noise Constant Frequency Operation e 1MHz Switching Frequency e Small Application Circuit e Regulated Output Current e Automatic Soft Start e No Inductors e Ig lt 1yA in Shutdown e Temperature Range 40 C to 85 C e 12 Pin TSOPJW Package AAT3123 23A e 16 Pin 4x4mm QFN and 14 Pin TSOPJW Packages AAT3124 Applications Color RGB Lighting Programmable Current Source White LED Backlighting White Photo Flash for DSCs VIN C1 C1 J 4pF y VOUT c1 BATTERY Cn Cour C2 1uF 1uF AAT3123 c2 AAT3123A IF C2 ot D1 peer D2 EN SET gt _ EN SET D3 D4 GND y D4 D3 D1 Ne VIN Ci Ct T 1pF x VOUT c1 VpaTTERY Cn Cour C2 we Tur AAT3i24 C2 e e EN SET gt EN SET Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e ww
24. f input and output voltages and does not require user intervention to maintain maximum efficiency The AAT3123 23A 24 requires only four external compo nents two 1uF ceramic capacitors for the charge pump flying capacitors C and C2 one 1yF ceramic input capacitor Cj and one 0 33uF to 1uF ceramic output capacitor Cour The LDO 1 5X charge pump output is converted into four D1 to D4 or six D1 to D4 and D5 to D6 constant current outputs to drive four or six individ ual LEDs with a maximum current of 20mA each The current source output magnitude is controlled by the EN SET serial data S Cwire interface The interface records rising edges of the EN SET pin and decodes them into 32 individual current level settings each 1dB apart see Table 1 Current Level Settings Code 32 is full scale and Code 1 is full scale attenuated by 31dB The modulo 32 inter face wraps states back to State 1 after the 32nd clock With each EN SET pulse the output current increases by 1dB To decrease the output current by 1dB 31 EN SET clock pulses are required The counter can be clocked at speeds up to 1MHz so intermediate states are not visi ble The first rising edge of EN SET enables the IC and initially sets the output LED current to 31dB the lowest setting equal to 525pA Once the final clock cycle is input for the desired brightness level the EN SET pin is held high to maintain the device output current at the pro grammed le
25. n is the output D1 and or D5 for the AAT3124 should always be connected to the load circuit The AAT3124 may be used to drive multiple LEDs having differing forward voltages Using feedback techniques the current in D1 to D4 output current sources are refer enced to the current in the LED connected to D1 In the AAT3124 six output version the D5 and D6 output cur Skyworks Solutions Inc e Phone 781 376 3000 e Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 11 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications rent sources are referenced to the current in D5 not to D1 If all six LEDs are of similar type the diodes will be matched in current maintaining uniform LED brightness despite variations in manufacturer production etc However if the diodes are dramatically different in type comprising a mix of high V and low V LEDs the AAT3124 has the capability to optimally and simultane ously drive up to four LEDs of one type and up to two LEDs of another type Such a feature can be useful for driving different color LEDs driving both display back light and photo flash LEDs or for driving main LCD and sub LCD display LED backlights from a single charge pump IC For example when driving independent RGB LEDs
26. resistance internal to a capacitor that is caused by the leads internal connec tions size or area material composition and ambient temperature Capacitor ESR is typically measured in mil liohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors Ceramic Capacitor Materials Ceramic capacitors less than 0 1uF are typically made from NPO or COG materials NPO and COG materials typically have tight tolerance and are stable over tem perature Large capacitor values are typically composed of X7R X5R Z5U or Y5V dielectric materials Large ceramic capacitors typically greater than 2 2uF are often available in low cost Y5V and Z5U dielectrics but capacitors greater than 1nF are typically not required for AAT3123 23A 24 applications Capacitor area is another contributor to ESR Capacitors that are physically large will have a lower ESR when compared to an equivalent material smaller capacitor These larger devices can improve circuit transient response when compared to an equal value capacitor in a smaller package size Test Current Channel Disable Each channel of the output is equipped with test current function A small amount of current 2pA is injected into each output current source to detect the presence of load LED Unused channels except channel 1 of AAT3123 23A and channel 5 of AAT3124 should be left open and will be automatically disabled instead of w
27. the green and blue LEDs typically require a high V to operate e g 3 7V while the red LED needs a low forward volt age e g 2V By connecting the green and blue diodes to outputs D1 to D4 and the red diodes to D5 and D6 good control and uniformity in brightness are maintained despite the 2V difference in the diode forward voltages The AAT3124 determines if the 1 5X charge pump circuit is needed based on the voltage on D1 and D5 whichever is higher If adequate voltage is available to drive the higher voltage LED of output D1 or D5 without the charge pump running the IC automatically switches into step down 1X mode to maximize efficiency Similarly if a 4V photo flash LED array is connected to outputs D1 through D4 with the outputs shorted togeth er and two 3 3V sub LCD display backlight LEDs are connected to outputs D5 and D6 then the AAT3124 can 12 optimally drive each set of LEDs at the programmed cur rent level see application schematics The photo flash can be disabled by an N channel switch connected in series with the photo flash LED The AAT3123 23A 24 has only one programmed value of current and does not allow for separate on off or bright ness control of each current source output This limita tion can easily be circumvented by introducing grounded source N channel MOSFET switches in series with the LEDs to turn any given LED or bank of LEDs on or off The various LEDs can be turned on and off indepen
28. tional Charge Pump for White LED Applications Characteristics Unless otherwise noted Vin 3 5V Cn Cour Ci Co LHF Ta 25 C EN SET 1Vidiv OUT 2Vidiv Vbione 1Vidiv lin 200mA div Vin 10mV div OUT 2V div Vbione 2V div lin 100mA div EN SET 1Vidiv Vbione 2Vidiv lin 100mA div Turn On to Full Scale Charge Pump o E Time 50us div Charge Pump to Load Switch 80mA Time 50us div Turn Off E O a E Er HEA a Le Time 200ps div Turn On to Full Scale Load Switch EN SET 1Vidiv OUT 2V div Vbione 2Vidiv ln PRE ee ee ee 100mA div Time 50ys div Load Switch to Charge Pump 80mA Vin 20mV div OUT 1Vidiv Vbione 1Vidiv lin 200mV div Time 50ys div 80mA Load Characteristics Vin ZN ZI Z RZ Vbione 20mV div Time 1us div Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High
29. vel The device is disabled 500us after the EN SET pin transitions to a logic low state Skyworks Solutions Inc e Phone 781 376 3000 Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Applications Information Constant Current Output Level Settings The constant current source output amplitude for out puts D1 to D6 are set via the serial interface according to a logarithmic scale where each code is 1dB greater than the previous code In this manner LED brightness appears linear with each increasing code count Because the outputs D1 to D6 are true independent constant cur rent sources the voltage observed on any single given output will be determined by the actual forward voltage Ve for the LED being driven Since the output current of the AAT3123 23A 24 is pro grammable through its single wire serial interface no PWM pulse width modulation or additional control cir cuitry is needed to control LED brightness This feature greatly reduces the burden on a microcontroller or sys tem IC to manage LED or display brightness allowing the user to set it and forget it Furthermore with its high speed serial interface 1MHz data rate the output current of the
30. w skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Pin Descriptions Pin AAT3123 23A AAT3124 AAT3124 TSOPJW 12 QFN44 16 TSOPJW 14 Symbol Function Flying capacitor 2 positive terminal Connect a 1uF capacitor be tween C2 and C2 Charge pump output Requires 1uF capacitor connected between this pin and ground Flying capacitor 1 negative terminal Flying capacitor 1 positive terminal Connect a 1uF capacitor be tween Ci and C1 D4 Current source output 4 If unused this pin should be left floating D3 Current source output 3 If unused this pin should be left floating D2 Current source output 2 If unused this pin should be left floating Di Current source output 1 Required reference current source Do not leave this pin floating EN SET Control pin using S Cwire serial interface IN Input power supply Requires 1uF capacitor connected between this pin and ground GND Ground C2 Flying capacitor 2 negative terminal D5 Current source output 5 Required reference current source Do not leave this pin floating D6 Current source output 6 If unused this pin should be left floating No connection Exposed paddle bottom connect to GND directly beneath package Hm O
31. wo Outputs ncp Charge Pump Section Efficiency Charge Pump Section tss Soft Start Time Fok Clock Frequency EN SET Veng Enable Threshold Low Vin 2 7V to 5 5V VencH Enable Threshold High Vin 2 7V to 5 5V tenset_Lo EN SET Low Time ten set_Ht Minimum EN SET High Time torr EN SET Off Timeout Input Current EN SET Input Leakage 1 The AAT3123 4 is guaranteed to meet performance specifications over the 40 C to 85 C operating temperature range and is assured by design characterization and cor relation with statistical process controls Skyworks Solutions Inc e Phone 781 376 3000 e Fax 781 376 3100 e sales skyworksinc com e www skyworksinc com 202135B e Skyworks Proprietary Information e Products and Product Information are Subject to Change Without Notice e February 26 2013 DATA SHEET AAT3123 23A 24 High Efficiency X 1 5X Fractional Charge Pump for White LED Applications Typical Characteristics Unless otherwise noted Vy 3 5V Cin Cour Cy Co 1pF Ta Efficiency Ipiope MA Quiescent Current mA Efficiency vs Input Voltage 4x20mA 100 95 90 Voiove 3 2V Voore 3 4V 85 80 75 70 65 60 55 50 Voiove 3 0V 27 29 31 33 35 3 7 39 41 43 45 47 49 5 1 Input Voltage V Ibiope VS Input Voltage 4x20mA 85 T T Voiope 3 2V T T
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