DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications General Description Features The AAT3143 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 AAT3143 can deliver current levels up to 80mA to drive white LEDs connected to the four current source outputs from a 2.7V to 5.5V input. The current source outputs may source up to 20mA each and may be operated individually or in parallel for driving higher-current LEDs. A low external parts count (two 1µF flying capacitors and two small 1µF capacitors at VIN and VOUT) makes the AAT3143 ideally suited for small battery-powered applications. • Input Voltage Range: 2.7V to 5.5V • PWM Brightness Control • Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum Efficiency and VF Coverage • Drives Four Low- or High-VF Type LEDs • Up to 20mA LED Current per Channel • No Inductors • 1MHz Switching Frequency • Small Application Circuit • AutoBias™ Technology • IQ <1µA in Shutdown • 2.85x3.0mm TSOPJW-12 Package Output current, and therefore brightness, is controlled via externally applied Pulse Width Modulation (PWM) control. Typically, PWM frequencies of up to 50kHz can be applied. Applications • Programmable Current Sources • White LED Backlighting • White Photo Flash for Digital Still Cameras The AAT3143 has a thermal management system to protect the device in the event of a short-circuit condition at the voltage output pin. Built-in soft-start circuitry prevents excessive inrush current during startup. A high charge pump switching frequency allows the use of very small external capacitors. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1µA. The AAT3143 is available in a Pb-free, space-saving, 2.85x3.0mm 12-pin TSOPJW package. Typical Application 2.7V to 5.5V IN C1+ CIN 1µF C1 1µF C1C2+ AAT3143 C2 1µF C2CP COUT 1µF D1 PWM/EN D2 EN/PWM D3 D4 GND D4 D3 D2 D1 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 1 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Pin Descriptions Pin # Symbol Function 1 2 3 4 5 6 7 8 9 10 11 12 C2+ CP C1C1+ D3 D2 D4 D1 EN/PWM IN GND C2- Flying capacitor 2 positive terminal. Connect a 1µF capacitor between C2+ and C2-. Charge pump output. Requires 1µF capacitor connected between this pin and ground. Flying capacitor 1 negative terminal. Flying capacitor 1 positive terminal. Connect a 1µF capacitor between C1+ and C1-. Current source output #3. Current source output #2. Current source output #4. Current source output #1. Enable/PWM control pin. Input power supply. Requires 1µF capacitor connected between this pin and ground. Ground. Flying capacitor 2 negative terminal. Pin Configuration TSOPJW-12 (Top View) C2+ CP C1C1+ D3 D2 2 1 12 2 11 3 10 4 9 5 8 6 7 C2GND IN EN/PWM D1 D4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Absolute Maximum Ratings1 Symbol VIN VEN/PWM IOUT2 TJ TLEAD Description Input Voltage EN/PWM to GND Voltage Maximum DC Output Current Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6 -0.3 to VIN + 0.3 80 -40 to 150 300 V V mA °C °C Value Units 0.625 160 W °C/W Thermal Information3 Symbol PD qJA Description Maximum Power Dissipation4 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. Based on long-term current density limitation. 3. Mounted on an FR4 board. 4. Derate 6.25 mW/°C above 25°C. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 3 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Electrical Characteristics1 CIN = CCP = C1 = C2 = 1.0µF; TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C, VIN = 3.5V. Symbol Description Conditions Input Power Supply VIN Operation Range ICC ISHDN IDX Operating Current I(D-Match) Shutdown Current Output Current Accuracy Current Matching2 hCP Charge Pump Efficiency Charge Pump Section FCLK Clock Frequency EN/PWM VEN(L) Enable Threshold Low VEN(H) Enable Threshold High FPWM Maximum PWM Frequency tON(MIN) Minimum Pulse Width Min Typ 2.7 VD1:D4 = 2.0V, CP = 1X No Load Current, CP = 1.5X EN/PWM = 0 IOUT = 20mA, TA = 25°C, VIN = 3.5V VD1:D4 = 3.6V, VIN = 3.5V VIN = 3.5V, IOUT(TOTAL) = 80mA, Measured from IN to CP Max Units 5.5 V 0.55 3 18 -3 5 1 22 3 20 ±0.5 mA µA mA % 93 % 1000 kHz 0.4 1.4 50 2 V V kHz µs 1. The AAT3143 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 I(D-Match) = (ID - IAVE)/IAVE. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Typical Characteristics VIN = 3.5V, CIN = CCP = C1 = C2 = 1µF, TA = 25°C, unless otherwise noted. Efficiency Turn-On to 1X Mode (100% Duty Cycle, 4x20mA/channel) (VIN = 4.2V) 100 VEN (1V/div) Efficiency (%) 90 80 VCP (2V/div) 70 60 VLED (2V/div) 50 40 30 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 IIN (100mA/div) Input Voltage (V) Time (50µs/div) Turn-On to 1.5X Mode Turn-On to 2X Mode (VIN = 3.5V) (VIN = 2.7V) VEN (1V/div) VEN (1V/div) VCP (2V/div) VCP (2V/div) VLED (2V/div) VLED (2V/div) IIN (50mA/div) IIN (50mA/div) Time (50µs/div) Time (50µs/div) LED Turn-On Delay LED Turn-On Delay (PWM Frequency = 500Hz) (PWM Frequency = 5kHz) VEN (2V/div) VEN (2V/div) VLED (2V/div) VLED (2V/div) ILED (10mA/div) ILED (10mA/div) Time (5µs/div) Time (1µs/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 5 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Typical Characteristics VIN = 3.5V, CIN = CCP = C1 = C2 = 1µF, TA = 25°C, unless otherwise noted. PWM Duty Cycle vs. LED Current 1.5X Mode PWM Characteristic (5kHz at 50% Duty Cycle) 20 VEN (2V/div) LED Current (mA) 18 ILED (20mA/div) IIN (100mA/div) VLED (2V/div) 100Hz 1kHz 16 14 10kHz 12 10 8 6 4 2 0 0 Time (50µs/div) 10 20 30 40 50 60 70 80 90 100 Duty Cycle (%) Line Response Line Response (1X Mode, 4x19mA Load) (1.5X Mode, 4x19mA Load) VIN (0.5V/div) VIN (0.5V/div) VLED (20mV/div) VLED (20mV/div) VCP (0.5V/div) VCP (0.5V/div) ID (10mA/div) ID (10mA/div) Time (1ms/div) Time (1ms/div) Input Current vs. Input Voltage Load Characteristics (4x10mA) (1.5X Mode, 4x15mA Load) 90 VF (20mV/div) Input Current (mA) 80 IIN (10mA/div) VCP (20mV/div) VDIODE = 3.4V 70 60 50 40 30 20 VDIODE = 3.0V 10 0 Time (1µs/div) 6 2.7 3.1 3.5 3.9 4.3 4.7 Input Voltage (V) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 5.1 5.5 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Typical Characteristics VIN = 3.5V, CIN = CCP = C1 = C2 = 1µF, TA = 25°C, unless otherwise noted. VIH and VIL vs. VIN 0.850 0.825 0.800 0.775 VIH 0.750 0.725 VIL 0.700 0.675 0.650 0.625 0.600 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Input Voltage (V) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 7 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Functional Block Diagram C1+ C1- C2+ C2- 1X/1.5X/2X Charge Pump IN CP Soft-Start Control 1MHz Oscillator Voltage Reference EN/PWM D/A D1 D/A D2 D/A D3 D/A D4 EN/PWM GND Functional Description The AAT3143 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 source output and sets the load switch and charge pump modes based on the input battery voltage and the current source output voltage. As the battery discharges over time, the AAT3143 charge pump is enabled when any of the four current source outputs nears dropout. The charge pump initially starts in 1.5X mode. If the charge pump output drops enough for any current source output to become 8 close to dropout, the charge pump will automatically transition to 2X mode. The AAT3143 requires only four external components: two 1µF ceramic capacitors for the charge pump flying capacitors (C1 and C2), one 1µF ceramic input capacitor (CIN), and one 0.33µF to 1µF ceramic charge pump output capacitor (COUT). The four constant current source outputs (D1 to D4) can drive four individual LEDs with a maximum current of 20mA each. The unused source outputs must be connected to GND, otherwise the part will operate only in 2X charge pump mode. The EN/PWM input allows the user to control the brightness of the four LEDs by PWMing up to 50kHz. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Applications Information EN/PWM Dimming Control LED brightness is controlled with the EN/PWM pin. By driving the pin with a PWM signal, a corresponding pulse-width modulated current will be driven through the LEDs. In this way, the duty cycle sets the LED brightness level. The resulting average current that flows through the LED is calculated as follows: ILED = DC · 20mA The EN/PWM pin can be driven with a wide range of PWM frequencies. Because of the short turn-on delay during high frequency PWM, a frequency as high as 50kHz can be used. A low PWM frequency can also be used without complication. One should consider that below 50Hz, the human eye can begin to see LED flicker, so it is recommended that users choose an adequate PWM frequency exceeding 50Hz. LED Selection Although the AAT3143 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, 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 sources 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 sources in the AAT3143 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. Capacitor Selection Careful selection of the four external capacitors CIN, C1, C2, and 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 capacitor size may be decreased. Capacitor Characteristics Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the AAT3143. 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. 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 typically measured in milliohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors. Ceramic Capacitor Materials Ceramic capacitors less than 0.1µF are typically made from NPO or C0G materials. NPO and C0G materials generally have tight tolerance and are very stable over temperature. Larger capacitor values are usually composed of X7R, X5R, Z5U, or Y5V dielectric materials. Large ceramic capacitors (i.e., greater than 2.2µF) are often available in low-cost Y5V and Z5U dielectrics, but capacitors greater than 1µF are not typically required for AAT3143 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. Thermal Protection The AAT3143 has a 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 of the CP pin. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012 9 DATA SHEET AAT3143 High Efficiency 1X/1.5X/2X Charge Pump with PWM Control for White LED Applications Ordering Information Package Marking1 Part Number (Tape and Reel)2 TSOPJW-12 ROXYY AAT3143ITP-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-12 2.85 ± 0.20 2.40 ± 0.10 0.20 + 0.10 - 0.05 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 7° NOM 0.055 ± 0.045 All dimensions in millimeters. 0.04 REF 0.15 ± 0.05 + 0.10 1.00 - 0.065 0.9625 ± 0.0375 3.00 ± 0.10 4° ± 4° 0.45 ± 0.15 0.010 2.75 ± 0.25 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 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. 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Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference. 10 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202142A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 6, 2012