DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer General Description Features The AAT3177A is a high output current, high efficiency, low noise, low profile charge pump DC/DC converter. The device is ideal for multi-functional LED photo-flash applications where solution cost, size, and efficiency are critical. • • • • • • • The AAT3177A is capable of driving a regulated output current up to 800mA. Output current levels can be easily programmed in 16 steps through Skyworks' Simple Serial Control™ (S2Cwire™) interface controlled by a single microcontroller GPIO line. This allows smooth transitions and flexible adjustment of brightness in flash or other lighting modes. The maximum output current can also be set with an external RSET resistor. • • • • • The tri-mode (1X/1.5X/2X) operation of the internal charge pump offers excellent power efficiency throughout the output current range for both flash and movie modes. Combined with a low external parts count (two 1μF flying capacitors and two small bypass capacitors at VIN and OUT), the AAT3177A is ideally suited for small battery-powered applications. Up to 800mA Output Current Tri-Mode 1X/1.5X/2X in Current Mode 16 Current Level Steps Set by S2Cwire Flash Auto-Timer (Active for High Current Levels Only) External RSET to Set Maximum Current <1μA of Shutdown Open LED, Short Circuit, and Over-temperature Protection Small Application Circuit No Inductors Automatic Soft Start 12-Pin TDFN 3x3mm Package -40°C to +85°C Temperature Range Applications • • • • • The AAT3177A has a thermal management system to protect the device in the event of a short-circuit condition at the output pin. Built-in soft-start circuitry prevents excessive inrush current during start-up. The shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1μA. Camcorders Camera Phones Digital Still Cameras PDAs and Notebook PCs Smart Phones The AAT3177A is available in a Pb-free, thermallyenhanced 12-pin 3x3mm TDFN package and is specified over the -40°C to +85°C temperature range. Typical Application 1μF C1+ 2.7V to 5.5V 1μF C1- C2+ CIN 4.7μF EN C2+ OUT VIN COUT 2.2μF AAT3177A EN/SET Flash LED FL CT RSET GND 0.1μF 187K Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 1 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Pin Descriptions Pin # Symbol 1 VIN 2 3 4 5 6 C1+ C1GND FL RSET 7 EN/SET 8 CT 9 10 C2C2+ 11 OUT 12 EP VIN Function Input power supply pin. Connect Pin 1 directly to Pin 12 and then to input supply voltage. Connect a 4.7μF or larger ceramic capacitor to ground. Flying capacitor C1 positive terminal. Connect a 1μF ceramic capacitor between C1+ and C1-. Flying capacitor C1 negative terminal. Ground connection. Controlled current sink. Connect the flash LED cathode to this pin. Connect resistor here to set maximum output current. Charge pump enable / set input control pin. When in the low state, the AAT3177A is powered down and consumes less than 1μA. When connected to logic high level, the AAT3177A charge pump is active. This pin should not be left floating. Flash timeout capacitor. Connect a 0.1μF capacitor between this pin and GND for a flash timeout of 1 second. Flying capacitor C2 negative terminal. Flying capacitor C2 positive terminal. Connect a 1μF ceramic capacitor between C2+ and C2-. Charge pump output. Connect a 2.2μF or larger ceramic capacitor to ground. Connect to flash LED anode to drive the LED. Input power supply pin. Connect Pin 12 directly to Pin 1 and then to input supply voltage. Exposed paddle (bottom). Connect to GND directly beneath package. Pin Configuration TDFN33-12 (Top View) VIN C1+ C1GND FL RSET 2 1 12 2 11 3 10 4 9 5 8 6 7 VIN OUT C2+ C2CT EN/SET Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Symbol VIN VEN VEN(MAX) IOUT TJ TS TLEAD Description Input Voltage EN to GND Voltage Maximum EN to Input Voltage Maximum Output Current Operating Temperature Range Storage Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6.0 -0.3 to 6.0 VIN + 0.3 1000 -40 to 150 -65 to 150 300 V V V mA °C °C °C Value Units 50 2 °C/W W Thermal Information2 Symbol JA PD Description Thermal Resistance Maximum Power Dissipation3 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. Mounted on an FR4 board. 3. Derate 20mW/°C above 40°C ambient temperature. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 3 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Electrical Characteristics1 CIN = 4.7μF, COUT = 2.2μF, C1 = C2 = 1.0μF; TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C, VIN = 3.6V. Symbol Description Conditions Power Supply Input Voltage Range VIN ICC Operating Current ISHDN(MAX) IOUT(MAX)2 IDX ILEDT VFLED TSS VRSET TSD TSD(HYS) EN/SET VEN(L) VEN(H) TEN/SET LO TEN/SET HI TEN/SET HI MAX TOFF TLAT Input Current VIN Pin Shutdown Current Maximum Output Current Output Current Accuracy Shorted LED Test Current LED Forward Voltage Detection Threshold Soft-Start Time RSET Pin Voltage Thermal Shutdown Threshold Thermal Shutdown Hysteresis Enable Threshold Low Enable Threshold High EN/SET Low Time Minimum EN/SET High Time Maximum EN/SET High Time EN/SET Off Timeout EN/SET Latch Timeout EN/SET Input Leakage Min Typ 2.7 1X, No Load Current 3.0 VIN 5.5, 1.5X Mode, No Load Current 3.0 VIN 5.5, 2X Mode, No Load Current EN = 0 VF = 3.6V Programmed for 600mA; RSET = 187k RSET = 187kΩ, Guaranteed by Design 300 2.0 3.0 540 1 Guaranteed by Design 1.6 Max Units 5.5 V μA 4.0 6.0 1.0 800 660 μA mA mA mA V 200 0.7 140 15 VIN = 2.7V VIN = 5.5V mA μs V °C 0.4 1.4 0.3 75 50 -1 75 500 500 1 V V μs ns μs μs μs μA 1. The AAT3177A is guaranteed to meet performance specification over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 2. Mounted on an FR4 board. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Typical Characteristics VIN = 3.6V, CIN = 4.7μF, COUT = 2.2μF, C1 = C2 = 1μF, TA = 25°C, unless otherwise noted. Efficiency vs. Supply Voltage Turn-On to 1X Mode (VIN = 4.2V; ILED = 150mA) 100 90 EN (2V/div) Efficiency (%) 80 70 ILED = 300mA 60 ILED = 150mA 50 40 VSINK (1V/div) 30 20 IIN (200mA/div) 10 0 VOUT (2V/div) 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 Time (200µs/div) Supply Voltage (V) Turn-On to 1.5X Mode Turn-On to 1X Mode (VIN = 3.2V; ILED = 150mA) (VIN = 4.2V; ILED = 600mA) EN (2V/div) EN (2V/div) VOUT (2V/div) VOUT (2V/div) VSINK (1V/div) VSINK (1V/div) IIN (200mA/div) IIN (500mA/div) Time (200µs/div) Time (200µs/div) Turn-On to 2X Mode Turn-Off from 1.5X Mode (VIN = 3.2V; ILED = 600mA) (VIN = 3.2V; ILED = 150mA) EN (2V/div) EN (2V/div) VOUT (2V/div) VF (1V/div) VSINK (1V/div) IIN (200mA/div) IIN (500mA/div) Time (200µs/div) Time (200µs/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 5 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Typical Characteristics VIN = 3.6V, CIN = 4.7μF, COUT = 2.2μF, C1 = C2 = 1μF, TA = 25°C, unless otherwise noted. Operating Characteristic Operating Characteristic (VIN = 3.3V; 1.5X Mode; ILED = 300mA) (VIN = 2.9V; 2X Mode; ILED = 300mA) VIN (100mV/div) VIN (100mV/div) VOUT (200mV/div) VOUT (200mV/div) VSINK (200mV/div) VSINK (200mV/div) Time (2µs/div) Time (2µs/div) LED Current vs. RSET Flash Timer Duration (Data = 1) (CT = 0.1µF) 1000 1.8 900 Flash Time (s) ILED (mA) 700 600 500 400 300 200 0 100 200 300 400 500 600 700 800 900 25°C 1.2 1.0 0.8 0.4 1000 85°C 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 RSET (kΩ Ω) Supply Voltage (V) EN/SET Latch Timeout vs. Supply Voltage EN/SET Off Timeout vs. Supply Voltage 350 350 300 250 200 25°C -40°C 150 100 85°C 50 EN/SET Off Timeout (µs) EN/SET Latch Timeout (µs) 1.4 0.6 100 300 250 200 150 25°C -40°C 85°C 100 50 0 0 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 Supply Voltage (V) 6 -40°C 1.6 800 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 Supply Voltage (V) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Typical Characteristics VIN = 3.6V, CIN = 4.7μF, COUT = 2.2μF, C1 = C2 = 1μF, TA = 25°C, unless otherwise noted. EN/SET High Threshold Voltage vs. Supply Voltage and Temperature EN/SET Low Threshold Voltage vs. Supply Voltage and Temperature 1.0 0.9 0.8 0.7 0.6 25°C 85°C 0.5 VEN(L) (V) VEN(H) (V) 0.9 1.0 -40°C -40°C 0.8 0.7 0.6 25°C 85°C 0.5 0.4 0.4 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 Supply Voltage (V) Supply Voltage (V) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 7 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Functional Block Diagram C1+ C1- C2+ C2- VIN Charge Pump Section 1 Charge Pump Section 2 OUT 1MHz Oscillator Soft-Start Control FL EN/SET System Control; S2Cwire; Timing RSET CT GND Functional Description The AAT3177A is a high efficiency, low noise, dual stage tri-mode 1X/1.5X/2X charge pump device intended for photo-flash LED applications. The device requires only four external components: two ceramic capacitors for the charge pump flying capacitors, one ceramic capacitor for CIN, and one ceramic capacitor for COUT. The charge pump delivers regulated load currents up to 800mA. The dual stage charge pump section contains soft-start circuitry to prohibit excessive inrush current during start-up. System efficiency is maximized with a tri-mode, dual stage charge pump topology. The internal clock oscillator at 1MHz allows the use of small external components. The tri-mode charge pump operation further optimizes power conversion efficiency. Depending upon the variance of load current (at different modes), input voltage, and nominal LED forward voltage, the charge pump will operate in a 1X, 1.5X, or 2X mode to generate the output voltage required to power the load for a given controlled 8 constant current. This results in significant power savings over voltage doubling architectures, especially when the LEDs are also operated at lower current levels in movie, viewing, or flashlight modes. S2Cwire Serial Interface The AAT3177A utilizes Skyworks’ single wire S2Cwire interface to enable/disable the charge pump and adjust the output current at 16 current levels. Each code defines the output current to be a percentage of the maximum current set by the resistor at the RSET pin (see Table 1). The S2Cwire interface records rising edges of the EN/SET pin and decodes them into 16 individual current level settings with Code 1 reserved for maximum current. Once EN/SET has been held in the logic high state for time TLAT (500μs), the programmed current is seen at the current source outputs and the internal data register is reset to 0. For subsequent current level programming, the number of rising edges corresponding to the desired code must be applied on the EN/SET pin. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer THI TLO TOFF T LAT EN/SET 1 2 n-1 n ≤ 16 0 Data Reg n 0 Figure 1: S2Cwire Serial Interface Timing. Data Output Current (% of IMAX) Flash Auto-Timer Enabled 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 100.01 89.11 79.41 70.81 63.1 56.2 50.1 44.7 39.8 35.5 31.6 28.2 25.1 22.4 20.0 0.0 Yes Yes Yes Yes No No No No No No No No No No No No Table 1: Current Level Settings. When EN/SET is held low for an amount of time longer than TOFF (500μs), the AAT3177A enters into shutdown mode and draws less than 1μA from VIN. Data and address registers are reset to 0 during shutdown. The flash timer is active for DATA values 1 through 41. For lower current settings (DATA 5 through 16) the flash timer is turned off to allow extended LED on time for movie mode applications. When changing from high current (DATA = 1-4) to lower current (DATA = 5-16) the timer will be ignored. When changing from low current to high current the timer will be reset and restarted. The charge pump will be reset during current level changes to allow the system to operate in the most efficient mode. Application Information Selecting a Timer Capacitor for CT The CT pin must be configured according to the desired flash function1. There are two options: connect a small valued capacitor or connect the pin to GND. Configure the timer feature for the AAT3177A by connecting a small valued capacitor between the CT pin and GND. The value of the capacitor will determine the timeout duration according to the following formula: T = CT · 10 s µF As an example, the result of connecting a 0.1μF capacitor between the CT pin and GND will be a 1 second timeout duration. Operationally, when the AAT3177A is enabled, it will automatically disable itself after 1 second. When using the auto-timer feature, select a CT capacitor value according to the formula above. To disable the auto-timer feature, connect the CT pin to ground. The result will be a small bias current of approximately 3μA. A large valued pull-down resistor should not be used for connecting the CT pin to GND. The CT pin can be connected directly to GND. If a pull-down resistor is preferred, it should be of low value (i.e., less than 10K). The primary considerations for selecting the capacitor type are leakage current and tolerance of the capacitor value. The auto-timer duration is determined by charging and discharging the timing capacitor with a small charging/discharging current of approximately 3μA. Avoid leaky capacitor types as they will distort the timeout duration. Select the capacitor value’s tolerance according to the desired time-out tolerance. 1. Flash Timer is enabled only for the four highest current level settings (DATA = 1, 2, 3, and 4). Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 9 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Real-Time Control of the CT Pin Flash/Torch Control Using the RSET Pin To achieve flash and torch mode control, the auto-timer can be enabled or disabled in real-time. This can be done by connecting a microcontroller or microprocessor GPIO port to the CT pin. An alternative method can be used for flash/torch control that eliminates the need to use the S2Cwire singlewire interface. By using any typical digital I/O port, an additional enable can be created (see Figure 3). To set up flash mode in real-time, enable the auto-timer by tri-stating the GPIO port. Do not drive the port high. It can only be set to high-impedance so that the CT capacitor can be charged and discharged by the AAT3177A. The I/O port output configuration can be an open-drain NMOS or open-drain PMOS, but not a push-pull type. The control will always act as an active-low flash enable or, equivalently, an active-high torch enable (see Table 2). To set up torch mode in real-time, disable the autotimer by driving the GPIO port low so that the CT pin will be pulled to GND through the GPIO port. EN ENFL Mode 0 0 1 1 0 1 0 1 Off Off Flash Torch AAT3177A Table 2: Flash/Torch Control Modes. EN/SET Tri-state = TMR ON Low = TMR OFF According to I/O port type, the following equations can be used to calculate appropriate resistor values. CT For an open-drain NMOS I/O port output configuration, the line is pulled low to GND or left floating, according to state. To calculate the appropriate R1 and R2 resistor values, first calculate the R1 resistor value needed for the desired torch level LED current: 0.1μF = 1 sec Figure 2: Enable or Disable the Auto-Timer in Real-Time for Flash/Torch Control. R1 = C1 1µF C1+ 2.7V to 5.5V 600mA · 187kΩ ILED (torch) C2 1µF C1- C2+ C2+ VOUT CIN 4.7µF EN EN/SET F1 CT ENCT CT COUT 2.2µF AAT3177A Flash LED R2 RSET ENFL GND R1 Figure 3: Flash/Torch Control Using the RSET Pin. 10 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Next, choose R2 based on the desired flash level LED current: R2 = R1 · 600mA · 187kΩ R1 · ILED (flash) - 600mA · 187kΩ The current and resistance values used in the equations come from the conditions placed on the IDX parameter of the Electrical Characteristics table. For examples of standard 1% values where the LED flash current level is targeted for 700mA, see Table 3. R1 (k) R2 (k) ILED Torch (mA) ILED Flash (mA) 920 732 649 562 193 205 210 223 122 153 173 200 703 701 707 703 Table 3: Open-Drain I/O Example Resistor Values. If the I/O port must be configured as an open-drain PMOS type output, the appropriate equations can be generated from these same concepts. As done in the previous example, the necessary values can then be calculated. As a reference, the equations applicable to the PMOS case are: R1 = 600mA · 187kΩ ILED (flash) VIO -1 0.7 R2 = ILED (torch) 1 R1 600mA · 187kΩ The value to use for VIO must come from the I/O supply voltage used in the system. 0.7V is the typical value of the VRSET parameter found in the Electrical Characteristics section of this datasheet. Device Power Efficiency The AAT3177A power conversion efficiency depends on the charge pump mode. By definition, device efficiency is expressed as the output power delivered to the LED divided by the total input power consumed. η= POUT PIN When the input voltage is sufficiently greater than the LED forward voltage, 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. The power conversion efficiency can be approximated by: η= VF · ILED VF ≈ VIN · IIN VIN Due to the very low 1X mode quiescent current, the input current nearly equals the current delivered to the LED. Further, the low-impedance bypass switch introduces negligible voltage drop from input to output. The AAT3177A further maintains optimized performance and efficiency by detecting when the input voltage is not sufficient to sustain LED current. The device automatically switches to 1.5X mode when the input voltage drops too low in relation to the LED forward voltage. In 1.5X mode, the output voltage can be boosted to 3/2 the input voltage. The 3/2 conversion ratio introduces a corresponding 1/2 increase in input current. For ideal conversion, the 1.5X mode efficiency is given by: η= VF VF · ILED = VIN · 1.5IIN 1.5 · VIN Similarly, when the input falls further, such that 1.5X mode can no longer sustain LED current, the device will automatically switch to 2X mode. In 2X mode, the output voltage can be boosted to twice the input voltage. The doubling conversion ratio introduces a corresponding doubling of the input current. For ideal conversion, the 2X mode efficiency is given by: η= VF VF · ILED = VIN · 2IIN 2 · VIN LED Selection The AAT3177A is designed to drive high-intensity white LEDs. It is particularly suitable for LEDs with an operating forward voltage in the range of 4.2V to 1.5V. The charge pump device can also drive other loads that have similar characteristics to white LEDs. For various load types, the AAT3177A provides a high-current, programmable ideal constant current source. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 11 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer 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 100m. A value of 1μF for the flying capacitors is a good starting point when choosing capacitors. If the LED current sinks are only programmed for light current levels, then the capacitor size may be decreased. These larger devices can improve circuit transient response when compared to an equal value capacitor in a smaller package size. Thermal Protection The AAT3177A has a 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 shortcircuit of the OUT pin. PCB Layout Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the AAT3177A. 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. To achieve adequate electrical and thermal performance, careful attention must be given to the PCB layout. In the worst-case operating condition, the chip must dissipate considerable power at full load. Adequate heat-sinking must be achieved to ensure intended operation. Equivalent Series Resistance The junction-to-ambient thermal resistance (JA) for the package can be significantly reduced by following a couple of important PCB design guidelines. 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 are often available in lower-cost dielectrics, but capacitors greater than 4.7μF are not typically required for AAT3177A 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. 12 Figure 4 illustrates an example of an adequate PCB layout. The bottom of the package features an exposed metal paddle. The exposed paddle acts, thermally, to transfer heat from the chip and, electrically, as a ground connection. The PCB area directly underneath the package should be plated so that the exposed paddle can be mated to the top layer PCB copper during the re-flow process. This area should also be connected to the top layer ground pour when available. Further, multiple copper plated thru-holes should be used to electrically and thermally connect the top surface paddle area to additional ground plane(s) and/or the bottom layer ground pour. The chip ground is internally connected to both the paddle and the GND pin. The GND pin conducts large currents and it is important to minimize any differences in potential that can result between the GND pin and exposed paddle. It is good practice to connect the GND pin to the exposed paddle area using a trace as shown in Figure 4. The flying capacitors C1 and C2 should be connected close to the chip. Trace length should be kept short to minimize path resistance and potential coupling. The input and output capacitors should also be placed as close to the chip as possible. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Evaluation Board User Interface The user interface for the AAT3177A evaluation board is provided by 3 buttons and a couple of connection terminals. The board is operated by supplying external power and pressing individual buttons or button combinations. The table below indicates the function of each button or button combination. To power-on the evaluation board, connect a power supply or battery to the DC- and DC+ terminals. Make the board’s supply connection by positioning the J1 jumper to the ON position. A red LED indicates that power is applied. The evaluation board is made flexible so that the user can disconnect the enable line from the microcontroller and apply an external enable signal. By removing the jumper from J2, an external enable signal can be applied to the board. Apply the external enable signal to the ON pin of the J2 terminal. Figure 4: Example PCB Layout. When applying an external enable signal, consideration must be given to the voltage level. The externally applied voltage cannot exceed the supply voltage that is applied to the VIN pins of the device (i.e., DC+). Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 13 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Button(s) Pushed1, 2 DATA MOVIE+DATA FLASH MOVIE DATA+FLASH+MOVIE Description Increments through the 16 data settings. Hold down to auto-cycle. Decrement the data setting. Hold down to auto-cycle. Generate a flash pulse. Current level determined by the DATA setting (defaults to DATA 1). Trim-pot VR4 sets timeout duration. Flash will not time out for low current settings (DATA=5-16). Toggle on/off movie mode illumination. Current level determined by the DATA setting. Leave on to see effects of changing DATA. Movie mode will time out for high current settings (DATA=1-4). Reset, shutdown. Table 5: Evaluation Board User Interface. Figure 5: AAT3177A Evaluation Board Top Side Layout. Figure 6: AAT3177A Evaluation Board Bottom Side Layout. 1. The ‘+’ sign indicates that these buttons are all pressed and released together. 2. Flash timeout duration is adjustable from 10ms to 2 seconds. Rotate trim pot VR4 clockwise to reduce the duration. When the timeout duration determined by the value of CT is set to be less than the VR4 setting, it will supersede. 14 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Evaluation Board Schematic DC- DC+ J1 VIN C4 4.7μF C1 1μF OSRAM OPTO Ceramos Flash LED LW C9SP D1 R8 187K U1 AAT3177A 1 2 3 4 5 6 VIN VIN C1+ VOUT C1C2+ GND C2F1 CT RSET EN/SET 12 11 10 9 8 7 C2 1μF R8 = 187K for 600mA C3 2.2μF C5 0.1μF R6 100K J2 DC+ R7 220 R3 1K DATA SW3 R2 1K R1 1K U2 1 VDD 2 GP5 3 GP4 4 GP3 FLASH SW2 MOVIE SW1 8 VSS GP0 76 GP1 5 GP2 VR4 POT10K C6 1uF R5 330 LED7 RED PIC12F675 Figure 7: AAT3177A Evaluation Board Schematic. Evaluation Board Component Listing Component Part Number Description Manufacturer U1 U2 D1 R1-R3 C1-C2 C3 C4 C5 C6 R5 R6 R7 R8 VR4 LED7 J1-J2 SW1-SW3 AAT3177A PIC12F675 LW C9SP Chip Resistor GRM18x GRM18x GRM18x GRM18x GRM31x Chip Resistor Chip Resistor Chip Resistor Chip Resistor EVN-5ESX50B14 CMD15-21SRC/TR8 PRPN401PAEN PTS645TL50 Tri-Mode High Eff. CP for White LED Flash; TDFN33-12 Package 8-bit CMOS, FLASH-based μC; 8-pin PDIP Package Ceramos TopLooker, High Brightness Flash LED 1K, 5%, 1/4W; 1206 1.0μF, 10V, X5R, 0603, Ceramic 2.2μF, 10V, X5R, 0603, Ceramic 4.7μF, 6.3V, X5R, 0603, Ceramic 0.1μF, 16V, X7R, 0603, Ceramic 1.0μF, 10V, X5R, 1206, Ceramic 330, 5%, 1/4W; 1206 100K, 5%, 1/4W; 1206 220, 5%, 1/4W; 1206 187K, 1%, 1/10W; 0603 10K POT; 3mm Squared SMD Red LED; 1206 Conn. Header, 2mm Switch Tact, SPST, 5mm Skyworks Microchip OSRAM OPTO Vishay Murata Murata Murata Murata Murata Vishay Vishay Vishay Vishay Panasonic-ECG Chicago Miniature Lamp Sullins Electronics ITT Industries Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012 15 DATA SHEET AAT3177A High Current, High Efficiency Charge Pump with Auto-Timer Ordering Information Package Marking1 Part Number (Tape and Reel)2 TDFN33-12 S8XYY AAT3177AIWP-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 Information3 TDFN33-12 Index Area 0.43 ± 0.05 0.1 REF C0.3 0.45 ± 0.05 2.40 ± 0.05 3.00 ± 0.05 Detail "A" 3.00 ± 0.05 1.70 ± 0.05 Top View Bottom View 0.23 ± 0.05 Pin 1 Indicator (optional) 0.05 ± 0.05 All dimensions in millimeters. 0.23 ± 0.05 0.75 ± 0.05 Detail "A" Side View 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. 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. 16 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202105A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • June 25, 2012