EVALUATION BOARD DATASHEET EV-153 AAT2847 EVAL: 4-Channel Backlight Driver with Dual LDOs Introduction The AAT2847 is a highly integrated power solution for single cell Li-Ion/Polymer based liquid crystal display (LCD) display applications. It includes a four channel light emitting diode (LED) backlight driver and two integrated 200mA low dropout voltage regulators (LDOs) as additional power supplies for display and camera related chipsets. The backlight driver in the AAT2847 is a low noise tri-mode DC/DC charge pump converter. Each of the four channels of the backlight driver is capable of delivering up to 20mA of bias current for white LEDs. The white LED (WLED) backlight bias current matching is 1%, which helps provide uniform display brightness. AnalogicTech’s AS2Cwire™ (Advanced Simple Serial Control™) serial digital interface is used to enable, disable, and set the current for each backlight LED channel. Each LED channel has sixteen available current level settings in three separate current scales, plus four available current level settings on a low level current scale. Each LED channel is equipped with built-in short circuit protection and auto disable functionality. A low shutdown current feature disconnects the load from the input and reduces quiescent current to less than 1μA. The AAT2847 is available in the thermally enhanced 20-pin 3x4x0.75mm TQFN package. Getting Started To apply power to the board, connect the supply by shorting the ON prong to the other prongs in the J1 header. After shorting the ON prong, the red LED7 should illuminate which indicates that power is connected to the AAT2847 and microcontroller (MCU). To allow the MCU to interact with the AAT2847, connect/short the ON prong to the other prongs in the J4 header. Also to enable LDOA, connect/short the ON prong to the middle prong on the J2 header. Conversely to enable LDOB, connect/short the ON prong to the middle prong on the J3 header. The user interface is provided by three buttons. The buttons are DATA, LIGHT, and SW. The modes of operation are detailed in Table 1. Each button handles a particular function: LIGHT turns on/off the D1-D4 LEDs, DATA increments the data register value of the targeted address, SW increments the target address of the AS2Cwire interface, and LIGHT+DATA+SW resets the MCU and turns off the AAT2847. When the DATA button is pressed and not released, the MCU will incrementally auto-cycle through the available values of the data register for the target address after a short delay. For a detailed device functionality description, regarding address functionality and available data register values, please consult the AAT2847 data sheet. Button(s) Pressed/Released LIGHT DATA SW LIGHT+DATA+SW Description Turns on/off D1-D4 LEDs Increments [cycles through when not released] data of targeted address (previously pressed/released SW button): see “SW” Increments the target address [default (address 0)]: Button Press/Release Address Decription 1st 3 Max Current Scale 2nd 4 Low Current Scale 3rd 5 Independent LED Control 4th, repeat 0 D1-D4 Current Control Reset. EN/SET is held logic low Table 1: User Interface Functionality. EV153.2007.10.1.0 www.analogictech.com 1 EVALUATION BOARD DATASHEET EV-153 AAT2847 EVAL: 4-Channel Backlight Driver with Dual LDOs Schematic DC+ DC+ DC+ 1 2 3 1 D1 D2 D3 2 1 3 2 3 D4 J1 J3 J2 R10 6 C4 18 17 D3 19 IN 14 PGND 12 C1- IN 11 OUT 7 EN/SET C1 13 C1+ FBA R11 15 EN/SET C3 C2+ 5 LDOB 16 10 4 ENB C2- C6 D4 D1 9 3 LDOB R13 D2 L DOA 2 8 1 GND FBB R14 ENA 20 R12 U1 AAT2847 C2 LDOA C5 R8 R9 Figure 1: AAT2847 Section Schematic of the Evaluation Board. J4 R6 EN/SET 3 2 1 R7 DC+ DC+ R1 R3 1 2 3 4 DATA C8 U2 R2 VDD GP5 GP4 GP3 VSS GP0 GP1 GP2 8 7 6 5 PIC12F675 R5 LED7 RED LIGHT SW Figure 2: PIC12F675 Section Schematic of the Evaluation Board. 2 www.analogictech.com EV153.2007.10.1.0 EVALUATION BOARD DATASHEET EV-153 AAT2847 EVAL: 4-Channel Backlight Driver with Dual LDOs Bill of Materials (BOM) Component U1 U2 C1-C3, C8 C4 C5, C6 D1-D4 LED7 R1-R3 R4 R5 R6 R7 R8-R11 R12-R13 R14 DATA, LIGHT, SW J1-J4 Part Number Description AAT2847-QI/QG PIC12F675 0603ZD105K C1608X5R1E105K GRM188R61C105K C1608X5R1A475K LMK107BJ475K 0603ZD225K C1608X5R1C225K GRM188R61A225K LW M67C CMD15-21SRC CRCW06031001F N/A CRCW0603330RF CRCW06030000F CRCW06031003F Open CRCW06031002F CRCW120650000F PTS645TL50 PRPN401PAEN 4-Channel Backlight Driver with Fixed Output Voltage Dual LDOs Microcontroller 1μF, ≥10V, X5R or X7R 4.7μF, ≥10V, X5R or X7R 2.2μF, ≥10V, X5R or X7R White LED Red LED; 1206 1kΩ, 1%, 1/10W, 0603 N/A 330Ω, 1%, 1/10W, 0603 0Ω, 1%, 1/10W, 0603 100kΩ, 1%, 1/10W, 0603 N/A 10kΩ, 1%, 1/10W, 0603 0Ω, 1%, 1/4W, 1206 Switch Tact, SPST, 5MM Connecting Header, 2mm Manufacturer AnalogicTech Microchip AVX TDK Murata TDK Taiyo Yuden AVX TDK Murata Osram CML Innovative Tech, Inc Vishay N/A Vishay Vishay Vishay N/A Vishay Vishay ITT Industries Sullins Electronics Table 2: AAT2847-QI/QG Component Listing. Component Part Number U1 AAT2847-EE U2 PIC12F675 0603ZD105K C1608X5R1E105K GRM188R61C105K C1608X5R1A475K LMK107BJ475K 0603ZD225K C1608X5R1C225K GRM188R61A225K LW M67C CMD15-21SRC CRCW06031001F N/A CRCW0603330RF CRCW06030000F CRCW06031003F CRCW06036042F CRCW06031203F CRCW06031603F CRCW06031002F CRCW120650000F PTS645TL50 PRPN401PAEN C1-C3, C8 C4 C5, C6 D1-D4 LED7 R1-R3 R4 R5 R6 R7 R8 R9, R11 R10 R12-R13 R14 DATA, LIGHT, SW J1-J4 Description 4-Channel Backlight Driver with Adjustable Output Voltage Dual LDOs Microcontroller 1μF, ≥10V, X5R or X7R 4.7μF, ≥10V, X5R or X7R 2.2μF, ≥10V, X5R or X7R White LED Red LED; 1206 1kΩ, 1%, 1/10W, 0603 N/A 330Ω, 1%, 1/10W, 0603 0Ω, 1%, 1/10W, 0603 100kΩ, 1%, 1/10W, 0603 60.4kΩ, 1%, 1/10W, 0603 120kΩ, 1%, 1/10W, 0603 160kΩ, 1%, 1/10W, 0603 10kΩ, 1%, 1/10W, 0603 0Ω, 1%, 1/4W, 1206 Switch Tact, SPST, 5MM Connecting Header, 2mm Manufacturer AnalogicTech Microchip AVX TDK Murata TDK Taiyo Yuden AVX TDK Murata Osram CML Innovative Tech, Inc Vishay N/A Vishay Vishay Vishay Vishay Vishay Vishay Vishay Vishay ITT Industries Sullins Electronics Table 3: AAT2847-EE Component Listing. EV153.2007.10.1.0 www.analogictech.com 3 EVALUATION BOARD DATASHEET EV-153 AAT2847 EVAL: 4-Channel Backlight Driver with Dual LDOs Printed Circuit Board Figure 3: AAT2847 Evaluation Board Top Layer (not to scale) 4 www.analogictech.com EV153.2007.10.1.0 EVALUATION BOARD DATASHEET EV-153 AAT2847 EVAL: 4-Channel Backlight Driver with Dual LDOs Figure 4: AAT2847 Evaluation Board Bottom Layer (not to scale). Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611 © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. 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All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. EV153.2007.10.1.0 www.analogictech.com 5