DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications General Description Features The AAT3159 is a low noise, constant frequency charge pump DC/DC converter that uses a tri-mode load switch (1X), fractional (1.5X), and doubling (2X) conversion to maximize efficiency for white LED applications. The device is capable of driving up to four channels of LEDs at up to 40mA per channel from a 2.7V to 5.5V input supply voltage. The current sinks may be operated individually or in parallel for driving higher-current LEDs. A low external parts count (two 1µF flying capacitors [C1 and C2] and two small 1µF capacitors [CIN and COUT]) makes this part ideally suited for small battery-powered applications. • Input Supply Voltage Range: 2.7V to 5.5V • Tri-Mode (1X/1.5X/2X) Charge Pump • Maximizes Efficiency • 1MHz Constant Switching Frequency • No Inductors, Low Noise Operation • Drives Four Channels of LEDs up to 40mA/ Channel • User-Programmable LED Current • Excellent LED Channel-to-Channel Current Matching • Digitally Programmable LED Current with Single-Wire S2Cwire Interface • 16 Current Levels From 40mA to 50µA • Low IQ (50µA) for Low Current Mode Operation • True Load Disconnect in Shutdown; IQ < 1µA • Built-In Thermal Protection • Built-In Auto-Disable for Open LED Circuit • Automatic Soft-Start Minimizes Inrush Startup Current • 2.85x3x1mm TSOPJW-14 Package Skyworks' patented single-wire Simple Serial Control (S2Cwire™) serial digital interface is used to enable, disable, and set the current for each LED with 16 levels from a maximum of 40mA down to 50µA. The maximum current level is programmed via an external resistor. To save power, low-current mode supply current will be as low as 50µA. Each output of the AAT3159 is equipped with built- in protection for VOUT short-circuit operation and auto-disable functionality for LED open-circuit conditions. Built-in soft-start circuitry prevents excessive inrush current during start-up. A low-current shutdown feature disconnects the load from IN and reduces quiescent current to less than 1µA. Applications • • • • Cellphones, DSC, Handheld Devices LED Photo Flash Programmable Current Sinks White LED Backlighting The AAT3159 is available in a Pb-free, space-saving 2.85x3x1mm TSOPJW-14 package. Typical Application C1 1µF VBATTERY 3.6V C1+ C2+ C1- C2- IN OUT AAT3159 CIN 1µF C2 1µF COUT 1µF GND WLEDs OSRAM LW M67C or equivalent D1 D2 D3 D4 D1 EN/SET S Cwire Serial Control 2 RSET 26.1kΩ EN/SET D2 SET D3 D4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 1 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Pin Descriptions Pin # Symbol 1 2 3 4 5 6 7 8 9, 11 10 12 13 14 D4 SET EN/SET C1+ C1OUT C2+ C2GND IN D1 D2 D3 Function Current sink input #4. Connect to the cathode of LED4. If not used, connect LED current setting resistor input/connection. S2Cwire serial interface control input for LED current magnitude control. Positive terminal of charge pump capacitor 1. Negative terminal of charge pump capacitor 1. Charge pump output. Connect all LED anodes to OUT. Positive terminal of charge pump capacitor 2. Negative terminal of charge pump capacitor 2. Ground. Input power supply connection. Current sink input #1. Connect to the cathode of LED1. If not used, connect Current sink input #2. Connect to the cathode of LED2. If not used, connect Current sink input #3. Connect to the cathode of LED3. If not used, connect D4 to the OUT pin. D1 to the OUT pin. D2 to the OUT pin. D3 to the OUT pin. Pin Configuration TSOPJW-14 (Top View) D4 1 14 D3 SET 2 13 D2 EN/SET 3 12 D1 C1+ 4 11 GND C1- 5 10 IN 6 9 7 8 OUT C2+ 2 GND C2- Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Absolute Maximum Ratings1 Symbol VN VN VN TJ TLEAD Description [IN, OUT, D1, D2, D3, D4] to GND [C1-, C2-, EN/SET, SET] to GND [C1+, C2+] to GND Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6 -0.3 to VIN + 0.3 -0.3 to VOUT + 0.3 -40 to 150 300 V V V °C °C Value Units 0.625 160 W °C/W Thermal Information2 Symbol PD qJA Description Maximum Power Dissipation3 Maximum Thermal Resistance 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. 2. Mounted on a FR4 board. 3. Derate 6.25mW/°C above 25°C. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 3 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Electrical Characteristics1 VIN = 3.6V; CIN = COUT = C1 = C2 = 1.0µF; TA = -40°C to +85°C, unless otherwise noted. TA = 25°C. Symbol Description Conditions Input Power Supply VIN Input Supply Voltage Range ICC ISHDN IDX I(D-Match) Operating Input Current Shutdown Current DX Pin Current Current Matching 1X to 1.5X or 1.5X to 2X TranVTH sition Threshold at Any DX Pin ISET Current Set Ratio VSET SET Pin Voltage Charge Pump Section TSS Soft-Start Time FCLK Clock Frequency EN/SET Logic Control VIL(EN/SET) Enable Logic Low Threshold VIH(EN/SET) Enable Logic High Threshold TEN/SET LO EN/SET Low Time TEN/SET HI MIN Minimum EN/SET High Time TEN/SET HI MAX Maximum EN/SET High Time TOFF EN/SET Off Timeout TLAT EN/SET Latch Timeout IEN/SET EN/SET Input Leakage 2 Min Typical values are Typ Max Units 5.5 1 3 V mA 1 µA µA 20 22 mA 0.5 1 % 2.7 1X Mode, 3.0 ≤ VIN ≤ 5.5, Active, No Load Current 1.5X Mode, 3.0 ≤ VIN ≤ 5.5, Active, No Load Current 2X Mode, 3.0 ≤ VIN ≤ 5.5, Active, No Load Current 50µA Setting, 1X Mode EN/SET = 0 TA= -40°C to +85°C, RSET = 26.1kW, Data = 1 (100%) VF:D1:D4 = 3.6V 0.3 1 1 50 18 ISINK/IRSET VIN = 2.7V VIN = 5.5V 150 mV 870 0.6 A/A V 100 1000 µs kHz 0.4 1.4 0.3 75 50 -1 75 500 500 1 V V µs ns µs µs µs µA 1. The AAT3159 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. 2. Current matching is defined as the deviation of any sink current from the average of all active channels. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Typical Characteristics VIN = 3.6V; CIN = COUT = C1 = C2 = 1.0µF; TA = -40°C to +85°C, unless otherwise noted. TA = 25°C. Efficiency vs. Input Voltage 100 Efficiency (%) 90 Turn-On to 1X Mode (VIN = 4.2V; 20mA/Channel Load) 20mA/channel VF = 3.4V 6mA/channel VF = 3V VEN/SET (1V/div) 80 70 VOUT (2V/div) VDX (1V/div) IIN (100mA/div) 60 50 500µA/channel VF = 2.7V 40 30 2.7 2.9 3.1 3.3 3.5 3.7 Typical values are 3.9 4.1 4.3 Input Voltage (V) 4.5 Time (100µs/div) Turn-On to 1.5X Mode Turn-On to 2X Mode (VIN = 3.5V; 20mA/Channel Load) (VIN = 2.8V; 20mA/Channel Load) VEN/SET (1V/div) VEN/SET (1V/div) VOUT (4V/div) VOUT (4V/div) VDX (1V/div) IIN (200mA/div) VDX (500mV/div) IIN (500mA/div) Time (100µs/div) Time (100µs/div) LED Current vs. Temperature Turn-Off from 1.5X Mode (20mA/Channel) (VIN = 3.5V; 20mA/Channel Load) 22.0 21.5 LED Current (mA) VEN/SET (1V/div) VF (4V/div) IIN (100mA/div) 21.0 20.5 ID4 ID2 19.5 19.0 ID3 18.5 18.0 -40 Time (100µs/div) ID1 20.0 -15 10 35 60 85 Temperature (°C) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 5 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Typical Characteristics VIN = 3.6V; CIN = COUT = C1 = C2 = 1.0µF; TA = -40°C to +85°C, unless otherwise noted. TA = 25°C. Operating Characteristics Typical values are Operating Characteristics (VIN = 3.7V; 1.5X Mode; 20mA/Channel Load; AC Coupled) (VIN = 3.5V; 1.5X Mode; 14mA/Channel Load; AC Coupled) VIN (20mV/div) VIN (20mV/div) VOUT (40mV/div) VOUT (40mV/div) VDX (20mV/div) VDX (20mV/div) Time (500ns/div) Time (500ns/div) Operating Characteristics Operating Characteristics (VIN = 2.9V; 2X Mode; 20mA/Channel Load; AC Coupled) (VIN = 2.9V; 2X Mode; 14mA/Channel Load; AC Coupled) VIN (20mV/div) VIN (20mV/div) VOUT (40mV/div) VOUT (40mV/div) VDX (40mV/div) VDX (40mV/div) Time (500ns/div) Time (500ns/div) Input Ripple vs. Input Voltage 14.0 20mA/channel Input Ripple (mV) 12.0 10.0 14mA/channel 8.0 6.0 4.0 10mA/ channel 2.0 0.0 2.7 3.1 3.5 3.9 4.3 Input Voltage (V) 6 4.7 5.1 5.5 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Typical Characteristics VIN = 3.6V; CIN = COUT = C1 = C2 = 1.0µF; TA = -40°C to +85°C, unless otherwise noted. TA = 25°C. 350 EN/SET Off Timeout (µs) 350 300 250 200 -40°C 150 100 85°C 25°C 50 300 250 -40°C 200 150 25°C 100 85°C 50 0 0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 Input Voltage (V) EN/SET Logic High Threshold (V) EN/SET Off Timeout vs. Input Voltage 2.7 EN/SET High Threshold Voltage vs. Input Voltage 1.4 1.2 -40°C 1.0 0.8 25°C 0.6 0.4 2.7 3.1 3.5 3.9 4.3 Input Voltage (V) 3.1 3.5 85°C 4.7 5.1 5.5 3.9 4.3 4.7 5.1 5.5 Input Voltage (V) EN/SET Logic Low Threshold (V) EN/SET Latch Timeout (µs) EN/SET Latch Timeout vs. Input Voltage Typical values are EN/SET Low Threshold Voltage vs. Input Voltage 1.4 1.2 1.0 -40°C 0.8 0.6 25°C 85°C 0.4 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 Input Voltage (V) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 7 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Functional Block Diagram C1+ C1- C2+ C2- 1x, 1.5x and 2x Charge Pump IN OUT Soft Start Control 1MHz Oscillator Voltage Reference EN/SET S2Cwire Interface 6x16 bit ROM D/A D1 D/A D2 D/A D3 D/A D4 Max Current Adjustment GND (2) Functional Description The AAT3159 is a tri-mode load switch (1X) and high efficiency (1.5X or 2X) charge pump device intended for white LED backlight applications. To maximize power conversion efficiency, an internal sensing circuit monitors the voltage required on each constant current sink input and sets the load switch and charge pump modes based on the input battery voltage and the current sink input voltage. As the battery discharges over time, the AAT3159 charge pump is enabled when any of the four current sink inputs nears dropout. The charge pump initially starts in 1.5X mode. If the charge pump output droops enough for any current source output to become close to dropout, the charge pump will automatically transition to 2X mode. The AAT3159 requires only four external components: two 1µF ceramic capacitors for the charge pump flying capacitors (C1 and C2), one 1µF 8 SET ceramic input capacitor (CIN), and one 0.33µF to 1µF ceramic output capacitor (COUT). The four constant current sink inputs (D1 to D4) can drive four individual LEDs with a maximum current of 40mA each. The unused sink inputs must be connected to VOUT; otherwise, the part will operate only in 2X charge pump mode. The S2Cwire serial interface enables the AAT3159 and sets the LED current magnitudes. Constant Current Output Level Settings The LED current magnitude is controlled by Skyworks' S2Cwire serial digital interface. The maximum current is programmed by an external resistor at the SET pin. Since the current sinks are programmable, no PWM (pulse width modulation) or additional control circuitry is needed to control LED brightness. This feature greatly Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications reduces the burden on a microcontroller or system IC to manage LED or display brightness, allowing the user to “set it and forget it.” With its high-speed serial interface (1MHz data rate), the LED current can be 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. The code settings for the AAT3159 are listed in Table 1. The S2Cwire serial interface has flexible timing. Data can be clocked-in at speeds greater than 1MHz, or much slower, such as 15kHz. After data is submitted, EN/SET is held high to latch the data. Once EN/SET has been held in the logic high state longer than TLAT (500µs), the programmed current becomes active. For subsequent current level programming, the number of rising edges corresponding to the desired code must be entered on the EN/SET pin. When EN/SET is held logic low longer than TOFF (500µs), the AAT3159 enters into shutdown mode and draws less than 1µA from IN. The internal data register is reset to zero during shutdown. S2Cwire Serial Interface The current level magnitude is controlled by Skyworks' Simple Serial Control (S2Cwire) serial interface. The interface records rising edges of the EN/SET pin and decodes them into 16 different states. The 16 current level settings available are indicated in Table 1. Data All LED Outputs D1 - D4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 100% 90% 79% 70% 62% 55% 48% 40% 31% 21% 15% 11% 1mA 500µA 100µA 50µA Auto-Disable Feature The AAT3159 is equipped with an auto-disable feature for each LED channel. After the IC is enabled and started up, a test current of 100µA (typical) is forced through each sink channel. The channel will be disabled if the voltage of that particular current sink (DX pin) does not drop to a specific threshold. This feature is very convenient for disabling an unused channel or during an LED fail short event. Thermal Protection The AAT3159 has built-in thermal protection circuit that will shut down the charge pump if the die temperature rises above the thermal limit, as is the case during a short-circuit event with the OUT pin. Table 1: AAT3159 LED Current Levels as a Percentage of the Maximum Level Set by RSET. S2Cwire Serial Interface Timing T HI T LO TOFF TLAT EN/SET 1 Data Reg 2 n 1 n <= 16 n 0 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 9 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Maximum LED Current vs. RSET Applications Information 45 40 LED Selection 35 Determining the Maximum LED Current Level The value of RSET determines the maximum LED current level. In the typical application, selecting RSET = 26.1kW results in 20mA/channel LED current. From this reference point, the RSET value required for other current levels can be calculated as: RSET = 20mA · 26.1kΩ ILED(MAX) A visual representation of the maximum LED current per channel versus RSET value is shown in Figure 1. Since the AAT3159’s LED current control circuits were optimzed for full-scale current settings higher than 15mA, RSET values smaller than or equal to 33.2kW are recommended. Brightness Control Using the SET Pin Additional methods of brightness control can be achieved with the SET pin. For example, using an additional resistor to connect the SET pin with a digital output provides a HI/LO control. Figure 2 illustrates a configuration of the SET pin utilizing two resistors. 10 30 ID (mA) Although the AAT3159 is specifically intended for driving white LEDs, the device can also be used to drive most types of LEDs with forward voltage specifications ranging from 2.0V to 4.7V. LED applications may include main and sub-LCD display backlighting, camera photoflash 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 D4 input current sinks are matched with negligible voltage dependence, the LED brightness will be matched regardless of the specific LED forward voltage (VF) levels. In some instances (e.g., in high-luminous-output applications such as photo flash), it may be necessary to drive high-VF type LEDs. The low dropout current sinks in the AAT3159 make it capable of driving LEDs with forward voltages as high as 4.7V at full current from an input supply as low as 3.0V. Outputs can be paralleled to drive high-current LEDs without complication. 25 20 15 10 5 0 10 15 20 25 30 35 40 45 50 55 60 65 70 75 RSET (kΩ) Figure 1: Maximum LED Current vs. RSET. AAT3159 HI/LO or VDAC R2 SET R1 Figure 2: SET Pin Configuration Using Two Resistors. When the digital output is asserted high, the resulting brightness level is LO and the individual LED currents are: 0.6V VIO ILED(LO) = ISET R // R - R 1 2 2 When the digital output is asserted low, the resulting brightness level is HI and the individual LED currents are: 0.6V ILED(HI) = ISET R // R 1 2 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Additionally, a digital-to-analog converter can be used with the SET pin to control the brightness level. The result is like the equation above, where VIO is replaced with VDAC: 0.6V VDAC ILED(LO) = ISET R // R - R 1 2 2 For cases where PWM dimming is preferred, the PWM signal can be applied directly to the SET resistor, as shown in Figure 3. In order for the LED current to go to zero, the voltage level of the PWM signal must be higher than the SET pin voltage of 0.6V. AAT3159 PWM R1 SET η= 4 · VLEDX · ILEDX ; x = 1, 2, 3 or 4 and IIN = 4 · ILEDX VIN · IIN VLEDX η= V IN Due to the very low 1X mode quiescent current, the input current nearly equals the total output current delivered to the LEDs. Further, the low resistance bypass switch introduces a negligible voltage drop from input to output. The AAT3159 further maintains optimized performance and efficiency by detecting when the input voltage is not sufficient to sustain the LED bias current. The device automatically switches to 1.5X mode when the input voltage drops too low in relation to the LED forward voltages. In 1.5X mode, the output voltage can be boosted to 1.5X the input voltage. The 1.5X conversion ratio introduces a corresponding 0.5X increase in input current. For ideal conversion, the 1.5X mode efficiency is given by: η= Figure 3: SET Pin Configuration for PWM Dimming Control. Device Power Efficiency The AAT3159’s power conversion efficiency depends on the charge pump mode of operation. By definition, device efficiency is expressed as the output power delivered to the LEDs divided by the total input power consumed. η= PLEDs VLED1 · ILED1 + ... + VLED4 · ILED4 = PIN VIN · IIN When the input voltage is sufficiently greater than the LED forward voltages, the device optimizes efficiency by operating in 1X mode. In 1X mode, the device is working as a bypass switch and passing the input supply directly to the output. By simplifying the conditions such that the LEDs have uniform VF, the power conversion efficiency can be approximated by: η= η= PLEDs VLED1 · ILED1 + ... + VLED4 · ILED4 = PIN VIN · IIN 4 · VLEDX · ILEDX ; x = 1, 2, 3 or 4 and IIN = 1.5(4 · ILEDX) VIN · IIN VLEDX η = 1.5V IN Similarly, when the input falls further, such that 1.5X mode can no longer sustain the LED bias currents, the AAT3159 will automatically switch to 2X mode. In 2X mode, the output voltage can be boosted to 2X the input voltage. The 2X conversion ratio introduces a corresponding 1X increase in input current. For ideal conversion, the 2X mode efficiency is given by: η= η= PLEDs VLED1 · ILED1 + ... + VLED4 · ILED4 = PIN VIN · IIN 4 · VLEDX · ILEDX ; x = 1, 2, 3 or 4 and IIN = 2(4 · ILEDX) VIN · IIN VLEDX η = 2V IN PLEDs VLED1 · ILED1 + ... + VLED4 · ILED4 = PIN VIN · IIN Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 11 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Device Switching Noise Performance Equivalent Series Resistance The AAT3159 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 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 backlight solutions. The AAT3159 soft-start feature prevents noise transient effects associated with inrush currents during start-up of the charge pump circuit. 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 typically measured in milliohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors. Capacitor Selection Ceramic capacitors less than 0.1µF are typically made from NPO or C0G materials. NPO and C0G materials typically have tight tolerance and are stable over temperature. Larger capacitor values are typically composed of X7R, X5R, Z5U, or Y5V dielectric materials. Large ceramic capacitors, typically greater than 2.2µF, are often available in low-cost Y5V and Z5U dielectrics, but capacitors greater than 1µF are typically not required for AAT3159 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. Careful selection of the four external capacitors (CIN, C1, C2, COUT) is important because they will affect turn-on time, output ripple, and transient performance. 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 100mW. 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 levels, then the capacitor size may be decreased. Capacitor Characteristics Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the AAT3159. Ceramic capacitors offer many advantages 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 nonpolarized. Low ESR ceramic capacitors help maximize charge pump transient response. Since ceramic capacitors are non-polarized, they are not prone to incorrect connection damage. 12 Ceramic Capacitor Materials PCB Layout To achieve adequate electrical and thermal performance, careful attention must be given to the printed circuit board (PCB) layout of the AAT3159. Figures 5 and 6 illustrate an example PCB layout for the AAT3159 (evaluation board). The flying capacitors (C1 and C2), input capacitor (C4), and output capacitor (C3) should be connected as close as possible to the IC. In addition to the external passive components being placed as close as possible to the IC, all traces connecting the AAT3159 should be as short and wide as possible to minimize path resistance and potential coupling. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Evaluation Board Schematic DC- TP3 GND DC+ TP1 TP4 GND TP2 DC- DC+ GND ON OFF GND J1 VIN JP6 R1 24.9K C1 1µF GND C3 1µF JP5 1 2 3 4 5 6 7 U1 D4 SET EN/SET C1+ C1VOUT C2+ D3 D2 D1 GND VIN GND C2- 14 13 12 11 10 9 8 C4 1µF AAT3159 C2 1µF GND GND JP1 JP2 JP3 JP4 D1 WHITE D2 WHITE D3 WHITE D4 WHITE R8 220Ω ON OFF J2 R7 100K GND VIN R4 1K CYCLE SW3 UP SW2 DOWN SW1 R3 1K R2 1K 1 2 3 4 U2 VDD GP5 GP4 GP3 PIC12F675 VR1 10K-POT 8 VSS 7 GP0 6 GP1 5 GP2 R5 330Ω C5 1µF GND R6 330Ω LED7 RED GND LED0 GREEN GND GND Figure 4: AAT3159 Evaluation Board Schematic. Evaluation Board Layout Figure 5: AAT3159 Evaluation Board Top Side Layout. Figure 6: AAT3159 Evaluation Board Bottom Side Layout. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 13 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Ordering Information Package Marking1 Part Number (Tape and Reel)2 TSOPJW-14 TLXYY AAT3159ITO-T1 Skyworks Green™ products are compliant with all applicable legislation and are halogen-free. For additional information, refer to Skyworks Definition of Green™, document number SQ04-0074. Package Information TSOPJW-14 2.85 ± 0.20 2.40 ± 0.10 0.20 +- 0.10 0.05 0.40 BSC Top View 0.04 REF 0.05 +- 0.05 0.04 Side View 0.15 ± 0.05 + 0.05 1.05 - 0.00 + 0.000 1.00 - 0.075 3.05 +- 0.05 0.10 4° ± 4° 0.45 ± 0.15 2.75 ± 0.25 End View All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 14 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 DATA SHEET AAT3159 AAT3159 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved. 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. Skyworks 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 hereunder, 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 DISCLAIMED. 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, INCLUDING 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 environmental 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 published 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 specifications 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. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202154A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 11, 2012 15