DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications General Description Features The AAT3369-1 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 CABC (Content Adaptive Brightness Control) applications. The AAT3369-1 is capable of driving 6 white LEDs at a total 126mA in a wide input range. The current sinks 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 IN and OUTCP) makes the AAT3369-1 ideally suited for small battery-powered applications. 2.7V to 5.5V Supply Voltage Range Drives up to 6 LEDs with up to 21mA each 126mA of Total Drive Current Charge Pump with Automatic Switching Between 1x and 1.5x Modes Linear LED Output Control • S2C Interface: 32 Steps from 21mA to 0.3mA • PWM Interface: Up to 100kHz from 1% to 100% Duty Cycle < 1.0µA Input Current in Shutdown Small Application Circuit Short Circuit Protection 0.9MHz Constant Frequency Automatic Soft-Start Limits Inrush Current -40°C to 85°C Temperature Range RoHS Compliant and Halogen Free TQFN3x2.2-18L Package Skyworks' S2Cwire serial digital input is used to enable and set maximum current to one of 32 levels for the LEDs. The maximum LED current ranges from 21mA to 0.3mA. A PWM input can also be adopted to dim the LED current from the maximum LED current to 1% of maximum LED current by PWM frequencies up to 100kHz. Low level at both S2Cwire and PWM inputs shutdown the IC with less than 1µA input current. Each output of the AAT3369-1 is equipped with built-in short-circuit protection and auto-recover when the fault condition is removed. The soft-start circuitry prevents excessive inrush current at start-up and mode transitions. The AAT3369-1 is available in the Pb-free, spacesaving TQFN3x2.2-18L package, and operates over the -40°C to +85°C ambient temperature range. Applications • • • • • Camera Phone LED Photo Flash/Torch MP3/MP4 Players PDAs and Notebook PCs Smart Phone Typical Application VIN 2.7V ~ 5.5V C1 1µF CIN 1µF PWM S2C CFLT 56nF C1+ C2+ C1C2IN OUTCP AAT3369-1 PWM EN/SET FCAP GND C2 1µF COUT 1µF WLEDs D1 D2 D3 D4 D5 D6 D1 D2 D3 D4 D5 D6 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 1 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Pin Descriptions Pin # Symbol Function 1, 18 2 3 4 5 6 7 OUTCP C1C1+ C2N/C IN GND O I I I P PG 8 PWM I 9 FCAP I 10 11 12 13 14 15 D1 D2 D3 D4 D5 D6 I I I I I I 16 EN/SET I 17 C2+ EP I Description Charge-pump output. Connect a 1µF bypass capacitor between this pin to ground. Flying capacitor C1 negative terminal. Connect a 1.0µF capacitor between C1+ and C1-. Flying capacitor C1 positive terminal. Connect a 1.0µF capacitor between C1+ and C1-. Flying capacitor C2 negative terminal. Connect a 1.0µF capacitor between C2+ and C2-. Not connected. Input power supply pin. Connect a 1µF bypass capacitor from this pin to ground. Ground connection. PWM signal input. Connect a PWM signal to dim the LED current linearly from the max LED current set by S2Cwire to 1% by PWM duty cycle. The default max LED current is 21mA when EN/SET is low. The frequency of the PWM signal may be up to 100kHz. Tie to ground if PWM is not used. PWM filter capacitor. For 50kHz PWM signal, a 56nF capacitor is recommended. If PWM control is not used, leave this pin open. LED driver current sink terminal D1. Connect LED cathode to this pin. Tie to OUTCP if not used. LED driver current sink terminal D2. Connect LED cathode to this pin. Tie to OUTCP if not used. LED driver current sink terminal D3. Connect LED cathode to this pin. Tie to OUTCP if not used. LED driver current sink terminal D4. Connect LED cathode to this pin. Tie to OUTCP if not used. LED driver current sink terminal D5. Connect LED cathode to this pin. Tie to OUTCP if not used. LED driver current sink terminal D6. Connect LED cathode to this pin. Tie to OUTCP if not used. Charge pump max LED current enable/set input. Connect a S2Cwire signal to set max LED current from 21mA to 0.2mA by 32 steps. Pull low together with PWM low to shut down AAT3369-1 with less than 1µA input current. Tie to ground if not used. Flying capacitor C2 positive terminal. Connect a 1.0µF capacitor between C2+ and C2-. Exposed pad. Connect to ground directly beneath the package. Pin Configuration TQFN3x2.2-18 (Top View) OUTCP C1C1+ C21 2 3 4 N/C IN GND PWM FCAP 5 18 6 17 7 16 8 15 9 14 OUTCP C2+ EN/SET D6 D5 13 12 11 10 D4 D3 D2 D1 2 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Absolute Maximum Ratings1 TA = 25OC unless otherwise noted. Symbol VIN VEN IOUT TJ TS TLEAD Description Input Voltage EN/SET, PWM to GND Voltage Maximum DC Output Current (continuous)2 Maximum Junction Operating temperature Storage Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6.0 -0.3 to 6.0 200 -40 to 150 -65 to 150 300 V V mA °C °C °C Value Units 65.83 38.90 1.5 °C/W °C/W W Thermal Information3 Symbol θJA θJC PD Description Thermal Resistance from Junction to Ambient Thermal Resistance from Junction to Case 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. 2. Based on long-term current density limitation. 3. Mounted on an FR4 board. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 3 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Electrical Characteristics1 VIN = 3.6V; CIN = 1µF; COUT = 1µF; CFLY = 1µF; CFLT = 56nF; TA = -40°C to 85°C, unless otherwise noted. Typical values are TA = 25°C. Symbol Description Conditions Input Power Supply VIN Input Voltage Range VOUT (max) Maximum Output Voltage IQ Operating Current ISHDN(MAX) Shutdown Current Charge Pump Section IOUT(MAX) Maximum Output Current fosc Oscillator Frequency tSS Charge Pump Set Up Time VIN_(TH) Charge Pump Mode Hysteresis LED Current Sink Outputs IDX IDX(MATCH) VD_(TH) Typ Max Units 5.5 V V 2.7 1x Mode, No Load Current, CP enabled 1.5x Mode, ID1 = FS, excluding ID1, VD2 = VD3 = VD4 = VD5 = VD6= IN EN = 0 1.5x to 1x Transition, ID1 = ID2 = ID3 = ID4 = ID5 = ID6 = 21mA Data 1 and PWM = 100%, TA = 25°C Data 32 only, TA = 25°C Current Marching Between Any Two Current Sinks3 VF; D1:D6 = 3.6V Charge Pump Mode Transition 1x to 1.5x Mode, ID1 = ID2 = ID3 = ID4 = ID5 = ID6 = 21mA 5.5 0.5 1 2 4 1.0 VF = 3.6V ISINK Current Accuracy2 S Cwire Control and EN/SET Control VEN/SET (L) EN/SET or PWM Input Low Threshold Voltage VEN/SET (H) EN/SET or PWM Input High Threshold Voltage ILEAK EN/SET Input Leakage tEN/SET(LOW) EN/SET Input Low Time tEN/SET(HI_MIN) EN/SET Minimum High Time tEN/SET(HIMAX) EN/SET Maximum High Time tEN/SET(OFF) EN/SET Input Off Timeout4 tEN/SET(LAT) EN/SET Latch Timeout5 PWM Control VPWM(L) PWM Input Low Threshold Voltage VPWM(H) PWM High Threshold Voltage TPWM(ON) PWM Turn On Delay FPWM(MIN) PWM Minimum Input Control Frequency FPWM(MAX) PWM Maximum Input Control Frequency FPWM(MIN) PWM Minimum Duty Cycle Thermal TSD TJ Thermal Shutdown Threshold THYS TJ Thermal Shutdown Hysteresis Min mA µA 126 0.9 100 mA MHz µs 300 mV -10 +10 ±15 % -5 +5 200 mV 2 0.4 1.4 -1 0.3 1 75 50 75 500 500 0.4 1.4 500 100 100 FPWM = 50kHz, Full Scale 1 140 20 V V mA µs ns µs µs µs V V µs Hz kHz % O C 1.The AAT3369-1 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. Determined by the average of all active channels. 3. Current matching is defined as the deviation of any sink current from the average of all active channels. 4. The EN/SET pin must remain logic low (less than VIL) for the duration of longer than 500μs to guarantee the off timeout. 5. The EN/SET pin must remain logic high (greater than VIH) for the duration of longer than 500μs to guarantee the latch timeout. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Typical Characteristics Operating Current vs. Input Voltage Operating Current vs. Input Voltage (1.5x Mode) 1.2 3.0 1.0 2.5 0.8 2.0 IQ (mA) IQ (mA) (1x Mode) 0.6 0.4 85°C 25°C -40°C 0.2 0.0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 85°C 25°C -40°C 1.5 1.0 0.5 0.0 2.7 5.5 3.1 3.5 Input Voltage (V) Input Current vs. Input Voltage 0.08 0.06 0.04 2.7 3.1 3.5 3.9 4.3 4.7 5.1 0.00 -40 5.5 -15 Input Voltage (V) 100% Frequency (MHz) 70% 60% 50% 3.1 3.5 3.9 4.3 Input Voltage (V) 60 85 0.92 80% 2.7 35 Frequency vs. Temperature VF = 3.3V, ILED = 21mA VF = 3.1V, ILED = 10mA VF = 2.9V, ILED = 5mA 90% 10 Temperature (°C) Efficiency vs. Input Voltage Efficiency (%) 5.5 0.02 0.04 40% 5.1 0.08 0.12 0.00 4.7 0.10 VF = 3.3V, ILED = 21mA VF = 3.1V, ILED = 10mA VF = 2.9V, ILED = 5mA 0.16 4.3 Shutdown Current vs. Temperature ISHDN (µA) Input Current (A) 0.20 3.9 Input Voltage (V) 4.7 5.1 5.5 0.91 0.90 0.89 0.88 0.87 -40 -15 10 35 60 85 Temperature (°C) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 5 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Typical Characteristics Current Matching vs. Input Voltage Current Matching vs. Input Voltage (S2C Data = 1) (S2C Data = 32) 0.50 0.44 21 D1 D2 D3 D4 D5 D6 19 17 15 Current (mA) Current (mA) 23 2.7 3.1 3.5 3.9 4.3 4.7 5.1 0.38 D1 D2 D3 D4 D5 D6 0.32 0.26 0.20 2.7 5.5 Input Voltage (V) 3.1 21.6 0.38 Current (mA) Current (mA) 0.40 21.0 D1 D2 D3 D4 D5 D6 -15 10 35 60 0.34 0.30 -40 85 1.0 0.8 0.8 VENL (V) VENH (V) 1.0 0.6 85°C 25°C -40°C 3.5 3.9 4.3 Input Voltage (V) 6 -15 10 4.7 35 60 85 EN Input Low Threshold Voltage vs. Input Voltage 1.2 3.1 D1 D2 D3 D4 D5 D6 1.2 2.7 5.5 Temperature (°C) EN Input High Threshold Voltage vs. Input Voltage 0.2 5.1 0.36 0.32 Temperature (°C) 0.4 4.7 (S2C Data = 32) 22.2 19.8 4.3 Current Matching vs. Temperature (S2C Data = 1) 20.4 3.9 Input Voltage (V) Current Matching vs. Temperature 19.2 -40 3.5 5.1 0.6 85°C 25°C -40°C 0.4 0.2 2.7 5.5 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 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 5.1 5.5 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Typical Characteristics EN/SET Input OFF Time vs. Input Voltage 450 450 390 390 330 tOFF (µs) tLAT (µs) EN/SET Input Latch Time vs. Input Voltage 270 85°C 25°C -40°C 210 150 2.7 3.1 3.5 3.9 4.3 4.7 330 270 85°C 25°C -40°C 210 5.1 150 2.7 5.5 3.1 3.5 Input Voltage (V) 1.2 1.2 1.0 1.0 0.8 0.6 85°C 25°C -40°C 0.4 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 Turn On to 1x Mode (VIN = 4.2V, CIN = COUT = 1μF, CF = 56nF, 21mA/Channel) VOUT (2V/div) ILED (20mA/div) 4.7 5.1 5.5 0.8 0.6 85°C 25°C -40°C 0.4 0.2 2.7 3.1 Input Voltage (V) EN (2V/div) IIN (200mA/div) 4.3 PWM Input Low Threshold Voltage vs. Input Voltage VPWML (V) VPWMH (V) PWM Input High Threshold Voltage vs. Input Voltage 0.2 3.9 Input Voltage (V) 0 Time (20ms/div) 4.7 5.1 5.5 Turn On to 1.5x Mode ILED (20mA/div) 0 4.3 (VIN = 3.6V, CIN = COUT = 1μF, CF = 56nF, 21mA/Channel) VOUT (2V/div) 0 3.9 Input Voltage (V) EN (2V/div) IIN (200mA/div) 0 3.5 0 0 0 0 Time (20ms/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 7 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Typical Characteristics Turn Off CP Mode Transient (VIN = 3.6V, CIN = COUT = 1μF, CF = 56nF, 21mA/Channel) EN (2V/div) IIN (200mA/div) VOUT (2V/div) (VIN = 3.6V to 4.2V, CIN = COUT = 1μF, 21mA/Channel) VIN (2V/div) VOUT (2V/div) 0 0 ILED (20mA/div) IIN (200mA/div) 0 Time (100µs/div) 0 0 0 Time (100µs/div) LED Current Transient LED Current Transient (VIN = 3.6V, CF = 56nF, 0.4mA to 21mA) VEN (2V/div) IIN (200mA/div) (VIN = 3.6V, 21mA to 0.4mA) VEN (2V/div) IIN (200mA/div) 0 0 VOUT (2V/div) 0 ILED (20mA/div) VOUT (2V/div) ILED (20mA/div) 0 Time (20ms/div) 0 0 Time (100µs/div) (VIN = 3.6V, CIN = COUT = 1μF, PWM with 100kHz, 50% Duty Cycle) VIN (AC coupled) (50mV/div) VOUT (AC coupled) (50mV/div) 0 0 IIN (100mA/div) IIN (100mA/div) 0 ILED (20mA/div) 0 0 0 0 0 Time (1µs/div) 8 0 1.5x Mode Operating Characteristics (VIN = 3.6V, CIN = COUT = 1μF, S2C Control Mode, 21mA/Channel) ILED (20mA/div) 0 1.5x Mode Operating Characteristics VIN (AC) (50mV/div) VOUT (AC) (100mV/div) 4.2V 0 0 ILED (20mA/div) 3.6V Time (1µs/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Functional Block Diagram IN C1+ C1C2+ C2- Dual-mode Charge Pump 1X/1.5X OUTCP 6 EN/SET D1 32-step S2Cwire Backlight Control D2 Control Logic PWM PWM Filter D3 D4 D5 D6 FCAP GND Functional Description The AAT3369-1 is a high efficiency charge pump white LED driver for portable applications. It can drive 6 white LEDs. The AAT3369-1 is a fractional charge pump and can multiply the input voltage by 1 or 1.5 times automatically. The charge pump switches at a fixed frequency of 0.9MHz. The internal mode-selection circuit automatically switches the mode between 1x and 1.5x based on the input voltage, output voltage and load current. This mode switching maximizes the efficiency throughout the entire LED load range. When the input voltage is high enough, the AAT3369-1 operates in 1x mode (no charge pump) to provide maximum efficiency. If the input voltage is too low to supply the programmed LED current, typically when the battery discharges and the voltage decays, the 1.5x charge pump mode is automatically enabled. When the battery is connected to a charger and the input voltage become high enough again, the device will switch back to 1x mode. The current sink magnitude is controlled by either the EN/SET serial data S2Cwire interface, a PWM interface or both. The S2Cwire interface records rising edges of the EN/SET pin and decodes them into 32 maximum individual current level settings from 21mA to 0.3mA each. The PWM interface receives an input switching frequency where the duty cycle is varied to dim or light the LED by changing the LED current between 100% and 1% of the maximum value for CABC applications to reduce or increase display power. To avoid switching noise and flicker in the output LED, the PWM input frequency is filtered via an internal resistor and small external capacitor to provide a continuous LED current. The AAT3369-1 is disabled by both EN/SET and PWM pulled low. Current Level Settings LED current level is set via Skyworks' Simple Serial Control (S2Cwire) interface in a linear scale where LED current of each code is smaller than the one of the previous code, as shown in Table 1. In this manner, the LED current decreases linearly with each increasing code. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 9 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications S2Cwire Data LED Current (mA) S2Cwire Data LED Current (mA) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 21.0 20.3 19.6 19.0 18.3 17.6 16.9 16.3 15.6 14.9 14.2 13.5 12.9 12.2 11.5 10.8 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 10.2 9.5 8.8 8.1 7.5 6.8 6.1 5.4 4.7 4.1 3.4 2.7 2.0 1.4 0.7 0.3 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). Exact counts of clock pulses for the desired current level should be entered on the EN/SET pin with a single burst of clocks. The counter refreshes each time a new burst clock input to the EN/SET pin is detected. A constant current is sunk as long as EN/SET remains in a logic high state. The current sink pins are switched off after EN/SET and PWM has remained low state for at least the tOFF timeout period (see Figure 1). PWM Control The AAT3369-1 also includes a PWM input as an additional means of providing dimming control for CABC application. Before the PWM signal is activated the EN/ SET pin must be held for the tLATCH period which sets the maximum current available to the LEDs. For example, if the maximum current of 19.8mA is required, then three rising edges of the EN/SET followed by tLATCH will allow 19.8mA to flow through the LED. By applying a variable duty cycle on the PWM pin this current can be adjusted. The minimum duty cycle is dependent upon the PWM frequency. Frequencies of up to 100kHz can be applied. To avoid output flicker and noise, the input control PWM frequency is filtered by an internal resistor in conjunction with an external filter capacitor. A 56nF ceramic capacitor is recommended. Table 1: S2C Data vs. LED Current.1 S2Cwire EN/SET Interface The LED current magnitude is controlled by the EN/SET pin using the S2Cwire interface. The interface records rising edges of the EN/SET pin and decodes them into 32 individual current level settings. Code 1 is full scale (21mA), and Code 32 is 0.3mA. The modulo 32 interface wraps states back to state 1 after the 32nd clock. The counter can be clocked at speeds up to 0.9MHz, so intermediate states are not visible. The first rising edge of EN/ SET enables the IC and initially sets the output LED current to full scale, the lowest setting equal to 0.3mA. Once the final clock cycle is input for the desired brightness level, the EN/SET pin should be held high to maintain the device output current at the programmed level. The device is disabled 500μs after the EN/SET and PWM pin enters a logic low state. The EN/SET timing is designed to To specify 21mA maximum LED current, there are two ways to realize the dimming. One is feeding a simple rising edge of EN/SET followed by tLATCH, then applying a pulse width modulation signal to the PWM pin to control the dimming; the other is keeping EN/SET low and applying a PWM signal directly with the duty cycle between 100% and 1%. THI TLO TOFF T LAT EN/SET 1 2 n-1 0 Data Reg n ≤ 32 n 0 Figure 1: S2Cwire Timing Diagram When PWM is Low. 1. The LED current accuracy is compromised at high DATA settings. 10 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Application Information LED current can also be programmed by PWM duty ratio control through the PWM pin when EN/SET is pulled low. The maximum LED current is 21mA at this condition. Up to 100kHz PWM signal is valid as the control signal. The high level duty ratio from 100% to 1% of the PWM signal controls the LED current linearly from 21mA to 1.1mA as shown in Figure 3. To get an ideal linear LED current control and avoid flicker, a suitable capacitor is required between FCAP and ground as CFLT. The CFLT value is related to the PWM frequency. Refer to the “Capacitor Selection” section of this datasheet to select a suitable capacitor to filter the PWM signal. Setting LED Current ILED (mA) The AAT3369-1's six LED current channels can be programmed by S2Cwire, PWM or S2Cwire with PWM at the same time. Table 1 and Figure 2 shows 32 steps of LED current setting by S2Cwire through the EN/SET pin. When only the S2C wire interface is used, connect the PWM pin to ground. 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 S2C Code Figure 2: LED Current Controlled by S2Cwire Only. 22 20 18 ILED (mA) 16 14 12 10 8 6 4 2 0 100 90 80 70 60 50 40 30 20 10 0 PWM Duty Cycle (%) Figure 3: LED Current Controlled by PWM Duty Ratio Only. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 11 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications S2Cwire and PWM signal can work together to control the LED current. S2Cwire is used to set the maximum LED current by changing the data register, and varying the PWM duty ratio changes the LED current value between 100% of the maximum value and 1% of maximum. Figure 4 illustrates the timing requirement. the charge pump. Tantalum and aluminum electrolytic capacitors are not recommended due to their high ESR. Some recommended capacitors are listed in Table 1. Ceramic capacitors with X5R temperature characteristic are preferred for most AAT3369-1 applications. These capacitors have good capacitor tolerance over a wide temperature range (X5R: ±15% over -55°C to +85°C). Capacitors with Y5V or Z5U temperature characteristic are generally not recommended for AAT3369-1. They have wide capacitance tolerance over special temperature (Y5V: +22%, -82% over -30°C to +85°C, Z5U: +22%, -56% over +10°C to +85°C). As an example, after three rising edges of S2Cwire and TLAT, 19.6mA per channel maximum LED current is set. Up to 100kHz PWM signal is employed to change the LED constant current linearly from 19.6mA to 0.2mA by varying the PWM duty ratio from 100% to 1%. Capacitor Selection CFLT is adopted as the capacitor of the RC filter to filter the PWM control signal to a constant voltage for internal LED current control. To internal 500kΩ R, and set the RC filter rejection frequency is 1/20 of the PWM frequency. The CFLT minimum value can be calculated by the following formula: The AAT3369-1 requires five capacitors for a typical application: CIN, COUT, C1, C2 and CFLT. Among them, CIN, C1, C2 and COUT are 1.5x mode charge pump necessary components. 1µF surface-mount multi-layer ceramic capacitors with less than 100mΩ Equivalent Series Resistance (ESR) are recommended. Though the ESR of the capacitors will not affect the ability of the capacitor to store energy, they have large effect on the performance such as equivalent output resistance, efficiency and output voltage ripple of CFLT ≥ 20 2πR · fPWM THI T LO TOFF T LAT EN/SET 1 2 n-1 n ≤ 32 >10µs PWM (Up to 100kHz) 0 Data Reg n 0 Figure 4: S2Cwire and PWM Control Timing. Manufacturer Murata TDK Part Number Value (µF) Voltage Temp. Co. ESR (mΩ) at 1MHz Case GRM188R61C105KA93 GRM185R60J105KE21 C1608X5R1C105K 1 1 1 16 6.3 16 X5R X5R X5R 18 16 5.5 0603 0603 0603 Table 1: Capacitor Recommendation. 12 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Table 2 shows some minimum CFLT values for different PWM frequency. For most application, 56nF is a suitable value. If PWM control is not used, CFLT is unnecessary. fPWM (kHz) Minimum CFLT (nF) 0.1 1 10 30 50 80 100 59 6 0.6 0.2 0.1 0.08 0.06 Table 2. Minimum CFLT Value Examples. -or- VF η (%) = V · 100 IN 1.5x Charge Pump Mode Efficiency The AAT3369-1 contains a fractional charge pump which will boost the input supply voltage in the event where VIN is less than the voltage required to supply the output. 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 be calculated by the following equation: LED Selection η= A good LED lighting application circuit is not only determined by the LED driver but also the LED selected. A higher luminous efficacy LED emits a higher amount of luminous flux (lumens) for a given power. Most LED manufacture datasheet provides the luminous efficacy by the luminous flux curve (LED forward current vs luminous flux). From the luminous flux curve, increasing the LED forward current may increase the LED light. While increased LED forward current also increases LED forward voltage with higher rating. The AAT3369-1 is designed to drive high-intensity white LEDs. It is particularly suitable for LEDs with an operating forward voltage VF in the range of 1.5V to 4.0V. To the white LEDs with lower forward voltage (VF), it switches the charge pump mode 1x and 1.5x mode automatically to maintain the continuous LED current accuracy at lower input voltage and obtains higher efficiency at the mode transfer input voltage point. Charge Pump Efficiency -or- POUT VF · IOUT = PIN VIN · IIN = VF · IOUT VF ≈ VIN · 1.5 · IOUT 1.5 · VIN VF η (%) = 1.5 · V · 100 IN Thermal and Short Circuit Protection When the device internal junction temperature reaches 125°C, the AAT3369-1 starts thermal protection by shutting down the charge pump. When the fault condition is removed and the junction temperature drops, the charge pump recovers automatically. When OUTCP is fault by being shorted to ground, the AAT3369-1 protects itself by limiting the input current to below 600mA, and shuts down the charge pump if the current exceeds this value. It will recover to normal operation automatically when the fault condition is removed. 1x Mode Efficiency Additional Applications The AAT3369-1's 1x mode is operational at all times and functions alone to enhance device power conversion efficiency when VIN is higher than the voltage across the load. When in 1x mode, voltage conversion efficiency is defined as output power divided by input power. The current sinks of the AAT3369-1 can be combined to drive higher current levels through a single LED. As an example, Figure 5 illustrates driving a single white LED with 186mA by connecting D1-D6 together to the LED cathode. An expression for the ideal efficiency (η) in 1X charge pump mode can be expressed as: η= POUT VF · IOUT V = ≈ F PIN VIN · IIN VIN Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 13 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications C1 1µF VIN 2.7V ~ 5.5V C1+ C2+ C1- C2- IN PWM C OUT 1µF D1 PWM 2 S C When designing a PCB for the AAT3369-1, the key requirements are: D1 Up to 126mA D2 EN/SET C FLT 56nF C2 1µF OUTCP AAT 3369-1 C IN 1µF Printed Circuit Board Layout Recommendations D3 FCAP D4 1. Place the flying capacitors C1 and C2 as close to the chip as possible; otherwise 1.5x mode performance will be compromised. 2. Place input and output decoupling capacitors as close to the chip as possible to reduce switching noise and output ripple. 3. Connect the exposed pad to GND plane to get best power dissipation. D5 D6 GND Figure 5: Higher Current, Single LED Application. 14 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Schematic and Layout U1 AAT 3369-1 J1 DC+ DC+ C1 1µ F 3 2 6 3 CIN 1µ F 7 DC- EN/SET PWM 9 R8 20k FCAP CF 56nF PWM R7 20k 17 4 18 1 C2 1µF COUT 1µF EP D1 D2 D3 D4 D5 D6 10 11 12 13 14 15 VMCU S1 DOWN D2 D3 D4 D5 D6 R1 0 R2 0 R3 0 R4 0 R5 0 R6 0 AAT 3369-1 White LED Driver EN/SET R10 R11 R12 1k 1k 1k D1 GND 16 8 V_MCU C2+ C2OUTCP OUTCP C1+ C1IN 1 2 3 4 U2 PIC12F675 VDD GP5 GP4 GP3 VSS GP0 GP1 GP2 C3 0.1µF 8 7 6 5 VMCU S2 UP R13 20k R9 1k S2Cwire and PWM Microcontroller LED2 Red 3 2 1 J2 S3 CYCLE Figure 6: AAT3369-1 Evaluation Board Schematic. Figure 7: AAT3369-1 Evaluation Board Top Side Layout. Figure 8: AAT3369-1 Evaluation Board Bottom Side Layout. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 15 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Component Part Number U1 AAT3369IDT-1 U2 R1, R2, R3, R4, R5, R6 R7, R8, R13 R9, R10, R11, R12 C1, C2, CIN, COUT C3 CF D1, D2, D3, D4, D5, D6 LED2 CYCLE, UP, DOWN PIC12F675 RC0603FR-070RL RC0603FR-0720KL RC0603FR-071KL GRM188R71C105K GRM188R71C104K GRM188R71C563K RS-0805UW 0805KRCT 6*6*5 Description Manufacturer High Efficiency, 6 Channel, 1X/1.5X Charge Pump for White LED Driver 8-Pin Flash-Based 8-Bit CMOS Microcontrollers Res 0Ω 1/10W 1% 0603 SMD Res 20kΩ 1/10W 1% 0603 SMD Res 1kΩ 1/10W 1% 0603 SMD Cap Ceramic 1μF 0603 X7R 16V 10% Cap Ceramic 0.1μF 0603 X7R 16V 10% Cap Ceramic 56nF 0603 X7R 16V 10% 20mA White LED 0805 Red LED 0805 12V 50mA Pushbutton Skyworks Microchip Yageo Murata Realstar HB E-LT Table 3: AAT3369-1 Evaluation Board Bill of Materials (BOM). 16 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 DATA SHEET AAT3369-1 High Efficiency, Six-Channel, 1X/1.5X Charge Pump for White LED Applications Ordering Information Package Part Marking1 Part Number (Tape and Reel)2 TQFN3x2.2-18L 9NXXY AAT3369IDT-1-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 TQFN3x2.2-183 Index Area Pin 1 Indicator (optional) 0.40 BSC 0.20 ± 0.05 0.203 REF 0.75 ± 0.05 3.00 ± 0.05 1.90 ± 0.05 0.30 ± 0.05 0.05 ± 0.05 Side View 2.20 ± 0.05 Top View 1.10 ± 0.05 Bottom View All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 3.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. Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. 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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202167A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 12, 2012 17