AAT3123 ANALOGICTECH | Alldatasheet

Document overview

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Technical content

Features

  • V IN Range: 2.7V to 5.5V
  • Dual Mode 1X and 1.5X Charge Pump for Maximum Efficiency
  • Drives Low-V F and High-VF Type LEDs
  • Up to Six 20mA Outputs (AAT3124)
  • Up to Four 20mA Outputs (AAT3123/23A)
  • 32-Position Logarithmic Scale with Digital Control
  • Simple Serial Control (S 2Cwire) Interface
  • Low Noise Constant Frequency Operation
  • 1MHz Switching Frequency
  • Small Application Circuit
  • Regulated Output Current
  • Automatic Soft Start
  • No Inductors Q <1µA in Shutdown
  • Temperature Range: -40°C to +85°C
  • 12-Pin TSOPJW Package (AAT3123/23A)
  • 16-Pin 4x4mm QFN Package (AAT3124)

Applications

  • Color (RGB) Lighting
  • Programmable Current Source
  • White LED Backlighting
  • White Photo Flash for DSCs Typical Application CIN 1µF VBATTERY COUT 1µF EN/SET 1µF 1µF D6 D5 D4 D3 VIN VOUT C1+ C1- C2+ C2- EN/SET GND AAT3124 D2 D1

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 2 3123.2005.12.1.4 Pin Descriptions Pin Configuration TSOPJW-12 QFN44-16 (Top View) (Top View) C1+ C1- N/C OUT C2+ C2- GND AAT3124 N/C IN EN/SET C2+ AAT3123 AAT3123A OUT C1- C1+ C2- GND IN EN/SET Pin # AAT3123/23A AAT3124 (TSOPJW-12) (QFN44-16) Symbol Function 1 10 C2+ Flying capacitor 2 positive terminal. Connect a 1 µF capacitor between C2+ and C2-. 2 9 OUT Charge pump output. Requires 1 µF capacitor connected between this pin and ground. 3 7 C1- Flying capacitor 1 negative terminal. 4 6 C1+ Flying capacitor 1 positive terminal. Connect a 1 µF capacitor between C1+ and C1-. 5 5 D4 Current source output #4. 6 4 D3 Current source output #3. 7 1 D2 Current source output #2. 8 16 D1 Current source output #1. 9 15 EN/SET Control pin using S 2Cwire serial interface. 10 14 IN Input power supply. Requires 1 µF capacitor connected between this pin and ground. 11 12 GND Ground. 12 11 C2- Flying capacitor 2 negative terminal. 2 D5 Current source output #5. 3 D6 Current source output #6. 8, 13 N/C No connection. EP Exposed paddle (bottom); connect to GND directly beneath package.

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 3123.2005.12.1.4 3 Absolute Maximum Ratings1 Thermal Information3 Symbol Description Value Units θJA Thermal Resistance QFN44-16 50 TSOPJW-12 160 °C/W PD Maximum Power Dissipation QFN44-164 2.0 TSOPJW-125 0.625 W Symbol Description Value Units VIN Input Voltage -0.3 to 6 V VOUT Charge Pump Output -0.3 to 6 V FB, VEN/SET FB or EN/SET to GND Voltage -0.3 to 6 V VEN/SET(MAX) Maximum EN/SET to Input Voltage 0.3 V IOUT

2 Maximum DC Output Current 150 mA

TJ Operating Junction Temperature Range -40 to 150 °C 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi- tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Based on long-term current density limitation. 3. Mounted on an FR4 board. 4. Derate 20mW/°C above 25°C. 5. Derate 6.25mW/°C above 25°C.

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 4 3123.2005.12.1.4 Electrical Characteristics1 CIN = COUT = C1 = C2 = 1.0µF; TA = -40°C to +85°C, unless otherwise noted. Typical values are T A = 25°C, VIN = 3.5V. Symbol Description Conditions Min Typ Max Units Input Power Supply VIN Operation Range 2.7 5.5 V Icc Operating Current 3.0 ≤ VIN ≤ 5.5, Active, 1.8 3.5 mA No Load Current ISHDN(MAX) Shutdown Current EN = 0 1 µA IDX Output Current V IN = 3.5V, Code = 32, TA = 25°C 18 20 22 mA ηCP Charge Pump Section Efficiency V IN = 3.5V, IOUT(TOTAL) = 120mA, 93 % Measured from IN to OUT Charge Pump Section TSS Soft-Start Time 200 µs FCLK Clock Frequency 1000 kHz EN/SET VEN(L) Enable Threshold Low V IN = 2.7V to 5.5V 0.5 V VEN(H) Enable Threshold High V IN = 2.7V to 5.5V 1.4 V TEN/SET LO EN/SET Low Time 0.3 75 µs TEN/SET HI Minumum EN/SET High Time 50 ns TOFF EN/SET Off Timeout 500 µs Input Current EN/SET Input Leakage -1 1 µA 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 correlation with statistical process controls.

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 3123.2005.12.1.4 5 Typical Characteristics Unless otherwise noted, VIN = 3.5V, CIN = COUT = C1 = C2 = 1µF, TA = 25°C. VIH and VIL vs. VIN 0.600 0.625 0.650 0.675 0.700 0.725 0.750 0.775 0.800 0.825 0.850 Input Voltage (V) VIH VIL Quiescent Current vs. Input Voltage Input Voltage (V) Quiescent Current (mA)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 VDIODE = 3.0V VDIODE = 3.2V VDIODE = 3.4V IDIODE vs. Input Voltage (4x10mA) Input Voltage (V) IDIODE (mA) VDIODE = 3.0V VDIODE = 3.2V VDIODE = 3.4V IDIODE vs. Input Voltage (4x20mA) Input Voltage (V) IDIODE (mA) VDIODE = 3.0V VDIODE = 3.2V VDIODE = 3.4V Efficiency vs. Input Voltage (4x10mA) Input Voltage (V) Efficiency (%) 100 VDIODE = 3.2V VDIODE = 3.4V VDIODE = 3.0V Efficiency vs. Input Voltage (4x20mA) Input Voltage (V) Efficiency (%) 100 VDIODE = 3.0V VDIODE = 3.2V VDIODE = 3.4V

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 6 3123.2005.12.1.4 Typical Characteristics Unless otherwise noted, VIN = 3.5V, CIN = COUT = C1 = C2 = 1µF, TA = 25°C. 80mA Load Characteristics Time (1µs/div) 20mV/div VIN OUT VDIODE Turn-Off Time (200µs/div) EN/SET (1V/div) VDIODE (2V/div) IIN (100mA/div) Load Switch to Charge Pump (80mA) Time (50µs/div) VIN (20mV/div) OUT (1V/div) VDIODE (1V/div) IIN (200mV/div) Charge Pump to Load Switch (80mA) Time (50µs/div) VIN (10mV/div) OUT (2V/div) VDIODE (2V/div) IIN (100mA/div) Turn-On to Full-Scale Load Switch Time (50µs/div) EN/SET (1V/div) OUT (2V/div) VDIODE (2V/div) IIN (100mA/div) Turn-On to Full-Scale Charge Pump Time (50µs/div) EN/SET (1V/div) OUT (2V/div) VDIODE (1V/div) IIN (200mA/div)

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 3123.2005.12.1.4 7 Functional Block Diagram 1x/1.5x Charge Pump Soft-Start Control 1MHz Oscillator Voltage Reference Quad Output DAC Dual Output DAC Current S2Cwire Interface 32 x 8 bit ROM Current Reference C1+ C1- C2+ C2- OUT D5* D6* GND EN/SET VIN *AAT3124 only 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 fractional charge pump consists of a low dropout linear voltage regulator followed by a 1.5X charge pump with multiple current- source outputs. To maximize power conversion efficiency, an internal feedback control sensing cir- cuit 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 out- put voltage level needed. This function significant- ly enhances overall device efficiency when the input voltage level is greater than the voltage required at the constant current source outputs. 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, whichev- er is greater. Switchover between the 1.5X (charge-pump) operating mode and the 1X (load switch) mode occurs automatically (as a function of input and output voltages) and does not require user intervention to maintain maximum efficiency. The AAT3123/23A/24 requires only four external components: two 1µF ceramic capacitors for the charge pump flying capacitors (C 1 and C2), one 1µF ceramic input capacitor (C IN), and one 0.33µF to 1µF ceramic output capacitor (C OUT). The LDO/1.5X charge pump output is converted into four (D1 to D4) or six (D1 to D4 and D5 to D6) con- stant current outputs to drive four or six individual LEDs with a maximum current of 20mA each. The current source output magnitude is controlled by the EN/SET serial data S 2Cwire interface. The inter- face records rising edges of the EN/SET pin and decodes them into 32 individual current level set- tings 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 interface wraps states back to State 1 after the 32nd clock. With each EN/SET pulse, the output current increas- es 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 intermedi- ate states are not visible. The first rising edge of EN/SET enables the IC and initially sets the output LED current to -31dB, the lowest setting equal to 525µA. 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 500µs after the EN/SET pin transitions to a logic low state.

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 8 3123.2005.12.1.4 Applications Information Constant Current Output Level Settings The constant current source output amplitude for outputs 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 man- ner, LED brightness appears linear with each increasing code count. Because the outputs D1 to D6 are true independent constant current sources, the voltage observed on any single given output will be determined by the actual forward voltage F) for the LED being driven. Normalized Output Current Settings 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1 2 3 4 5 6 7 8 9 1 01 11 21 31 41 51 61 71 81 92 02 12 22 32 42 52 62 72 82 93 03 13 2 Code Normalized IOUT (D1 to D6) Since the output current of the AAT3123/23A/24 is programmable through its single-wire serial inter- face, no PWM (pulse width modulation) or addi- tional control circuitry is needed to control LED brightness. This feature greatly reduces the burden on a microcontroller or system 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 AAT3123/23A/24 can changed successively 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). IOUT IOUT Code (mA) Code (mA) 1 0.549 17 3.529 2 0.627 18 4.000 3 0.706 19 4.471 4 0.784 20 5.020 5 0.863 21 5.647 6 1.020 22 6.353 7 1.098 23 7.059 8 1.255 24 7.922 9 1.412 25 8.941 10 1.569 26 10.039 11 1.804 27 11.216 12 1.961 28 12.627 13 2.275 29 14.118 14 2.510 30 15.843 15 2.824 31 17.804 16 3.137 32 20.000

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 3123.2005.12.1.4 9 EN/SET Serial Interface The current source output magnitude is controlled by the EN/SET pin, using AnalogicTech’s Simple Serial Control (S 2Cwire) interface. The interface records rising edges of the EN/SET pin, and decodes them into 32 individual current level set- tings each 1dB apart. Code 32 is full scale, and Code 1 is full scale attenuated by 31dB. The modu- lo 32 interface wraps states back to State 1 after the 32nd 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 initially sets the output LED current to -31dB, the lowest setting equal to 525µA. 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 programmed level. The device is disabled 500µs 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 reach- es full capacity after the soft-start time (T SS). During the soft-start time, multiple clock pulses may be entered on the EN/SET pin to set the final output current 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 t OFF timeout period. EN/SET Timing EN/SET Code 1 2 3 OFFOFF tHI tLO tOFF LED Selection The AAT3123/23A/24 is specifically intended for driv- ing white LEDs. However, the device design will allow the AAT3123/23A/24 to drive most types of LEDs with forward voltage specifications ranging from 2.0V to 4.3V. 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 generated from a varying input voltage. Since the D1 to D6 output cur- rent sources are matched with negligible voltage dependence, LED brightness will be matched regardless of the specific LED forward voltage (V levels. In some instances (e.g., in high luminous output applications such as photo flash), it may be neces- sary to drive high-V F 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 telephone handsets or other communica- tion 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 backlight solutions. The AAT3123/23A/24 soft-start feature prevents noise transient effects associated with inrush currents during start-up of the charge pump circuit.

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 10 3123.2005.12.1.4 Power Efficiency and Device Evaluation The charge pump efficiency discussion in the follow- ing 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 per- cent value comparing input power over output power. Since the AAT3123/23A/24 outputs are pure con- stant 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 measurement. For any given application, white LED forward voltage 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 applica- tion should 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 constant current setting. Depending upon the case of V IN being greater than the specific voltage seen across the load on D1 (or D5 when the AAT3124 is used) the device will oper- ate in load switch mode. If the voltage seen on the constant current source output is less than V IN, then the device will operate in 1.5X charge pump mode. Each of these two modes will yield different efficien- cy 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 opera- tional at all times and functions alone to enhance device power conversion efficiency when the con- dition exists where V IN 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: The expression to define the ideal efficiency ( η) can be rewritten as: -or- Charge Pump Section Efficiency The AAT3123/23A/24 contains a fractional charge pump which will boost the input supply voltage in the event where V IN is less than the voltage required on the constant current source outputs. The efficiency (η) 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 ( η) 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 (η) can be rewritten as: -or- η(%) = 100 VOUT 1.5VIN η = POUT = VOUT × IOUT = VOUT PIN VIN × 1.5IOUT 1.5VIN η = POUT PIN η(%) = 100 VOUT VIN η = POUT = VOUT × IOUT = VOUT PIN VIN × IOUT VIN η = POUT PIN

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 3123.2005.12.1.4 11 For a charge pump with an output of 5 volts and a nominal input of 3.5 volts, the theoretical efficiency is 95%. Due to internal switching losses and IC quiescent current consumption, the actual efficien- cy can be measured at 93%. These figures are in close agreement for output load conditions from 1mA to 100mA. Efficiency will decrease as load current drops below 0.05mA or when the level of V IN approaches V OUT. Refer to the Typical Characteristics section of this datasheet for meas- ured plots of efficiency versus input voltage and output load current for the given charge pump out- put voltage options. Capacitor Selection Careful selection of the four external capacitors C IN, C1, C2, and COUT is important because they will affect turn-on time, output ripple, and transient per- formance. Optimum performance will be obtained when low equivalent series resistance (ESR) ceramic capacitors are used. In general, low ESR may be defined as less than 100m Ω. A value of 1µF for all four capacitors is a good starting point when choosing capacitors. If the LED current sources are only programmed for light current lev- els, then the capacitor size may be decreased. Capacitor Characteristics Ceramic composition capacitors are highly recom- mended over all other types of capacitors for use with the AAT3123/23A/24. Ceramic capacitors offer many advantages over their tantalum and alu- minum electrolytic counterparts. A ceramic capac- itor typically has very low ESR, is lowest cost, has a smaller PCB footprint, and is non-polarized. Low ESR ceramic capacitors help to maximize charge pump transient response. Since ceramic capaci- tors are non-polarized, they are not prone to incor- rect connection damage. Equivalent Series Resistance ESR is an important characteristic to consider when selecting a capacitor. ESR is a resistance internal to a capacitor that is caused by the leads, internal connections, size or area, material composition, and ambient temperature. Capacitor ESR is typi- cally measured in milliohms for ceramic capacitors and can range to more than several ohms for tanta- lum or aluminum electrolytic capacitors. Ceramic Capacitor Materials Ceramic capacitors less than 0.1µF are typically made from NPO or C0G materials. NPO and C0G materials typically have tight tolerance and are sta- ble over temperature. Large capacitor values are typically composed of X7R, X5R, Z5U, or Y5V dielectric materials. Large ceramic capacitors, typ- ically greater than 2.2µF, are often available in low- cost Y5V and Z5U dielectrics, but capacitors greater than 1µF 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 (~2µA) is injected into each output current source to detect the presence of load (LED). Unused channels that are tied to ground or LED load fail short will be automatically disabled instead of wasting the pro- grammed output current. The test current in the AAT3123A is higher (~150µA) 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 connected in parallel to drive a single power output. Any combination of outputs (D1 to D6) may be connected in parallel. The max- imum total output current is a sum of how many current sources are parallel connected. This fea- ture is particularly useful to power pre-manufac-

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 12 3123.2005.12.1.4 tured 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 refer- ence circuit bases feedback from current sensed on the D1 and D5 outputs. For best operation, the only requirement for this type of application 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 referenced to the current in the LED connected to D1. In the AAT3124 (six-output ver- sion), the D5 and D6 output current 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, pro- duction, etc. However, if the diodes are dramatically different in type comprising a mix of high-V F and low-VF LEDs, the AAT3124 has the capability to optimally and simultaneously 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; driv- ing both display backlight 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, the green and blue LEDs typically require a high V F to operate (e.g., 3.7V), while the red LED needs a low forward voltage (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 unifor- mity in brightness are maintained despite the 2V dif- ference in the diode forward voltages. The AAT3124 determines if the 1.5X charge pump circuit is need- ed 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 connect- ed to outputs D1 through D4 (with the outputs shorted together) and two 3.3V sub-LCD-display backlight LEDs are connected to outputs D5 and D6, then the AAT3124 can optimally drive each set of LEDs at the programmed current 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 brightness control of each current source output. This limitation can easily be circumvented by introducing grounded source N-channel MOS- FET 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 independently, simultaneously, or multiplexed to produce any vari- ety of lighting effects. By reprogramming the cur- rent source (via the serial interface) between switching transitions, 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 F LEDs (up to 4.3V) at full current from a 3V input condition. The AAT3123/23A/24 is well suited for battery-powered applications using single-cell lithium-ion (li-ion) bat- teries (4.2V to 2.8V), lithium-polymer batteries, and 3-series connected dry cells (3.6V).

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 3123.2005.12.1.4 13 Additional Application Circuits Typical AAT3123/23A Application Circuit. AAT3123/23A Driving a Display Module with Four Paralleled White LEDs. CIN 1µF VBATTERY COUT 1µF EN/SET 1µF 1µF D2 D3 D4 VIN VOUT C1+ C1- C2+ C2- EN/SET GND AAT3123 AAT3123A Display Module RB1 RB2 RB3 RB4 Resistor R is optional CIN 1µF VBATTERY COUT 1µF EN/SET 1µF 1µF D4 D3 D2 D1 VIN VOUT C1+ C1- C2+ C2- EN/SET GND AAT3123 AAT3123A

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 14 3123.2005.12.1.4 AAT3124 Driving Two Groups of Paralleled White LEDs (e.g., main and sub-LCD backlights). AAT3124 Driving a High-Current Photo-Flash LED. CIN 1µF VBATTERY COUT 1µF EN/SET 1µF 1µF D2 D3 D4 D5 VIN VOUT C1+ C1- C2+ C2- EN/SET GND AAT3124 D1 D6 Photo-Flash LED Resistor R is optional *In some applications, white LED forward voltages (VF) 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: RB = VSOURCE - VF IF CIN 1µF VBATTERY COUT 1µF EN/SET 1µF 1µF D2 D3 D4 VIN VOUT C1+ C1- C2+ C2- EN/SET GND AAT3124 RB1 RB2 RB3 RB4 RB5 RB6 Resistor R is optional Resistor R is optional

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 3123.2005.12.1.4 15 AAT3124 Driving Two Groups of Paralleled White LEDs (with series N-channel switch). AAT3124 Separately Driving RGB Color LEDs. CIN 1µF VBATTERY COUT 1µF EN/SET 1µF 1µF BLU2RED1 VIN VOUT C1+ C1- C2+ C2- EN/SET GND AAT3124 GRN1 Enable Green Enable Red Enable Blue RED2 GRN2 BLU1 CIN 1µF VBATTERY COUT 1µF EN/SET 1µF 1µF D2 D3 D4 VIN VOUT C1+ C1- C2+ C2- EN/SET GND AAT3124 Enable Display Backlight Enable Keyboard Backlight

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 16 3123.2005.12.1.4 Additional Application Circuits AAT3124 Driving Common-Anode RGB Color LED. CIN 1µF VBATTERY COUT 1µF EN/SET 1µF 1µF RED VIN VOUT C1+ C1- C2+ C2- EN/SET GND AAT3124 GRN Enable Green Enable Red Enable Blue BLU Common-Anode RGB Color LED

High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 3123.2005.12.1.4 17

Ordering Information

Package Information

All dimensions in millimeters. 0.20 + 0.10 - 0.05 0.055 ± 0.045 0.45 ± 0.15 7° NOM 4° ± 4° 3.00 ± 0.10 2.40 ± 0.10 2.85 ± 0.20 0.15 ± 0.05 0.9625 ± 0.0375 1.00 + 0.10 - 0.065

0.04 REF

0.010 All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. Package Marking 1 Part Number (Tape and Reel)2 Description TSOPJW-12 IRXYY AAT3123ITP-20-T1 4-Channel Output TSOPJW-12 OIXYY AAT3123AITP-20-T1 4-Channel Output with Increased Start-Up Current (see “Test Current/Channel Disable” section on page 11) QFN44-16 ISXYY AAT3124ISN-20-T1 6-Channel Output 1. XYY = assembly and date code. 2. Sample stock is generally held on all part numbers listed in BOLD.

All dimensions in millimeters. 4.000 ± 0.050 Pin 1 Dot By Marking 2.400 ± 0.050 0.600 ± 0.050 4.000 ± 0.050 2.280 REF

0.650 BSC

0.900 ± 0.050 Pin 1 Identification R0.030Max 13 16 0.450 ± 0.050 0.0125 ± 0.0125 0.203 ± 0.025 0.330 ± 0.050 Top View Bottom View Side View AAT3123/23A/24 High Efficiency 1X/1.5X Fractional Charge Pump for White LED Applications 18 3123.2005.12.1.4 Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality con- trol techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.