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A8241 AiT Semiconductor Inc. www.ait-ic.com 4CHANNEL WHITE LED DRIVER DESCRIPTION FEATURES The A8241 is a CMOS based White/Blue LED Low 60mV Dropout at 20mA driver with stand-alone capability. The driver is 4% LED Current Matching primarily designed for LED backlighting of LCD display powered by Li-ion battery with its high efficiency, low sandby current and wide range of input supply voltage. The A8241 is suitable for applications such as portable device display and keypad backlighting. In portable application, six channel LED solutions are popular. The A8241 is available in SOT-26 package. ORDERING INFORMATION Package Type Part Number APPLICATION Next-Generation Wireless Handsets PDAs, Palmtops, and Handy Terminals Digital Cameras, Camcorders Battery-Powered Equipment A8241E6R SOT-26 E6 A8241E6VR Note R: Tape & Reel V: Green Package Typical Application AiT provides all Pb free products Suffix “ V” means Green Package REV1.0 -AUG 2009 RELEASED - -1- A8241 AiT Semiconductor Inc. www.ait-ic.com 4CHANNEL WHITE LED DRIVER PIN DESCRIPTION Top View Pin # Symbol Function 1 EN 2 GND Ground 3 LED4 LED4 Pin. Connect to the LED cathode, leave it open or connect to GND if unused. 4 LED3 LED3 Pin. Connect to the LED cathode, leave it open or connect to GND if unused. 5 LED2 LED2 Pin. Connect to the LED cathode, leave it open or connect to GND if unused. 6 LED1 LED1 Pin. Connect to the LED cathode, leave it open or connect to GND if unused. Enable Pin. Active high, with an internal 141kΩ pull-down resistor. ABSOLUTE MAXIMUM RATINGS Supply Input Voltage, VIN −0.3V to 6V The other pins −0.3V to 6V Power Dissipation, PD @ TA = 25°C SOT-23-6 0.4W Package Thermal Resistance(Note 4) SOT-23-6, θJA 250oC/W Lead Temperature (Soldering, 10 sec.) Operation Temperature Range 260oC −40°C to 85°C Junction Temperature Storage Temperature Range 150 oC −40°C to 85°C ESD Susceptibility (Note 2) HBM (Human Body Mode) MM (Machine Mode) -2kV -200V Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. REV1.0 -AUG 2009 RELEASED - -2- A8241 AiT Semiconductor Inc. www.ait-ic.com 4CHANNEL WHITE LED DRIVER RECOMMENDED OPERATING CONDITIONS Parameter Min Suply Voltage VDD Typ Max Unit 2.7 5.5 V - < 5.5 V Junction Temperature Range -40 125 °C Ambient Temperature Range -40 85 °C Other Pins (Except GND) ELECTRICAL CHARACTERISTICS (VIN = VEN=3.6V, TA = 25°C, Unless Otherwise specification) Parameter Min Typ Max Unit Suply Voltage VDD 2.7 - 5.5 V Output Current ILED 18 20 22 mA IOUT=200mA(NOTES5) - - 60 mV Quiescent Current IQ No Load - 250 300 μA Shutdown Current ISD VEN=0V - 0.1 1 μA LED Current Matching -4 - 4 Enable High Level Input Voltage VIH 2.7 - - V Enable Low Level Input Voltage VIL - - 0.6 V Startup Time - 20 - μs 300 650 900 μs Thermal Shutdown Temperature TSD - 145 - oC Hysteresis Temperature - 20 - oC Dropout Voltage of any LEDx Current Source VDO Shutdown Delay Time TOFF Conditions VEN=0V % Note1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note2. Devices are ESD sensitive. Handling precaution recommended. Note3. The device is not guaranteed to function outside its operating conditions. Note4. θJA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. Note5. Dropout voltage of current source is the minimum voltage needed at pin LEDx to provide the specified current. REV1.0 -AUG 2009 RELEASED - -3- A8241 AiT Semiconductor Inc. www.ait-ic.com 4CHANNEL WHITE LED DRIVER TYPICAL PERFORMANCE CHARACTERISTICS 1. Efficiency vs. Supply Voltage 2. LED Current vs. Supply Voltage 3. 4. LED Current vs. LED Dropout Voltage REV1.0 -AUG 2009 RELEASED - Quiescent Current vs. Supply Voltage -4- AiT Semiconductor Inc. www.ait-ic.com A8241 4CHANNEL WHITE LED DRIVER BLOCK DIAGRAM A8241 REV1.0 -AUG 2009 RELEASED - -5- A8241 AiT Semiconductor Inc. www.ait-ic.com 4CHANNEL WHITE LED DRIVER DETAILED INFORMATION The A8241 works with a wide range of supply voltage, from 2.7V to 6.0V. The forward voltage of commercial white/blue LED is in the range of 2.9V to 3.5V at current level of 20mA. Proper selection of the LED to match the supply voltage can fully utilize the Li-ion battery. For example, there is 1% to 3% power left in the Li-ion battery when its voltage reaches 3.275V. So a LED with a forward voltage value of 3.2V can use up to 99% of the battery power under normal working condition. When the voltage of the battery drops below 3.2V, the current through the LED (hence the brightness) starts to decrease. Due to its uniquely designed current regulator, A8241 offer low output dropout and provide superior efficiency performance over standard Inductive boost type and capacitive charge pump type LED driver. The EN pin controls the ON/OFF state of the device. A high level state turns on the device and a low level turns off the device, results in the low off state current. The pin needs to be terminated since a floating level of the EN pin will cause the instability of the device. The sink current has a constant value of 20mA. The brightness of the LED can be adjusted by controlling the duty cycle of the A8241 LEDn output. This can be accomplished by applying a PWM signal to the EN pin. In A8241, the internal power on sequence presents a delay time of 6us from CE pin to LEDn pin. Hence, In order To normally modulate the output of LEDn in every cycle, the width of dimming signal applied CE pin have to be no less than 6ux, For example, when a dimming signal of 20KHz is applied, the minimum range of dimming is about 12%, that is, the average output current on each channel is 2.4mA. REV1.0 -AUG 2009 RELEASED - -6- A8241 AiT Semiconductor Inc. www.ait-ic.com 4CHANNEL WHITE LED DRIVER PACKAGE INFORMATION Dimension in SOT-26 (Unit: mm) Tape Dimension REV1.0 -AUG 2009 RELEASED - Reel Dimension -7- A8241 AiT Semiconductor Inc. www.ait-ic.com 4CHANNEL WHITE LED DRIVER IMPORTANT NOTICE AiT Semiconductor Inc. (AiT) reserves the right to make changes to any its product, specifications, to discontinue any integrated circuit product or service without notice, and advises its customers to obtain the latest version of relevant information to verify, before placing orders, that the information being relied on is current. AiT Semiconductor Inc.'s integrated circuit products are not designed, intended, authorized, or warranted to be suitable for use in life support applications, devices or systems or other critical applications. products in such applications is understood to be fully at the risk of the customer. Use of AiT As used herein may involve potential risks of death, personal injury, or servere property, or environmental damage. In order to minimize risks associated with the customer's applications, the customer should provide adequate design and operating safeguards. AiT Semiconductor Inc. assumes to no liability to customer product design or application support. AiT warrants the performance of its products of the specifications applicable at the time of sale. REV1.0 -AUG 2009 RELEASED - -8-