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AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 1 - DESCRIPTION FEATURES The A8176 is a constant frequency, SOT -25 current mode step-up converter intended for small, low power applications. The A8176 switches at 1.0MHz and allows the use of tiny, low cost capacitors and inductors 2mm or less in height. Int ernal soft -start results in small inrush current and extends battery life. The A8176 operates from an input voltage as low as 3.0V and can generate 24V at up to 80mA from a 5V supply. The A8176 includes current limiting, and thermal overload protection to prevent damage in the event of an output overload. The A8176 is available in SOT-25 package.

ORDERING INFORMATION

SPQ: 3,000pcs/Reel A8176E5R A8176E5VR Note V: Halogen free Package R: Tape & Reel AiT provides all RoHS products  Integrated 0.7Ω Power MOSFET  400μA Quiescent Current  3.0V to 5.5V Input Voltage  1.0MHz Fixed Switching Frequency  Internal 1.2A Switch Current Limit  Adjustable Output Voltage  Internal Compensation  Up to 24V Output Voltage  Over 85% Efficiency  Available in SOT-25 Package APPLICATION  OLED Biasing  LCD Bias Supply  White LED Driver  PDAs  Digital Still Cameras TYPICAL APPLICATION Figure 1. Basic Application Circuit with A8176

AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 2 - PIN DESCRIPTION Top View Pin # Symbol Function

1 SW Switching Pin

2 GND Ground Pin

3 FB Feedback Pin. Feedback voltage is 1.23V

4 EN Chip Enable (Active High)

5 VIN Input Supply

VIN, Supply Input Voltage -0.3V~ 6V SW, Switching Pin -0.3V~ 30V Other Pins -0.3V~ 6V PD, Power Dissipation @ TA=25°C SOT-25 0.392W Package Thermal Resistance NOTE 1 SOT-25, θJA 255°C/W Lead Temperature (Soldering, 10 sec.) 260°C Junction Temperature 150°C Storage Temperature Range -65°C ~150°C Stress beyond above listed “Absolute Maximum Ratings” may lead permanent damage to the device. These are stress ratings only and operations of the device at these or any other conditions beyond those indicated in the operational sections of the specifications are not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. NOTE1: 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.

AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 3 - RECOMMENDED OPERATING CONDITIONSNOTE2 Parameter Min. Max. Units Junction Temperature Range -40 125 °C Ambient Temperature Range -40 85 °C NOTE2: The device is not guaranteed to function outside its operating conditions.

ELECTRICAL CHARACTERISTICS

VIN=3.7V, TA = 25°C, unless otherwise specified Parameter Conditions Min. Typ. Max. Unit Operating Input Voltage 3 - 5.5 V Under Voltage Lockout 2 2.2 2.45 V Under Voltage Lockout Hysteresis - 100 - mV Current (Shutdown) VEN=0V - 1 5 uA Quiescent Current VFB=1.5V,NO switch - 400 600 uA Supply Current VFB=0V,switch - 1 2 mA Switching Frequency 0.75 1 1.25 MHz Maximum Duty Cycle VFB=0V 90 92 - % EN Input High Voltage 1.4 - - V EN Input Low Voltage - - 0.5 V FB Voltage 1.193 1.23 1.267 V FB Input Bias Current VFB=1.23V - -10 - nA SW ON Resistance - 0.7 - Ω SW Current Limit VIN=3.7V, Duty Cycle=50% - 1.2 - A SW Leakage VSW=24V - - 1 uA Soft Start - 200 - us Over Temperature Shutdown - 160 - °C Over Temperature Hysteresis - 40 - °C

AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 4 - TYPICAL PERFORMANCE CHARACTERISTICS 1. Iq vs. VIN 2. f vs. VIN 3. VFB vs. VIN 4. VEN vs. VIN 5. Power On/Off from EN (CH1:EN,CH2:VO) 6. Normal Operation (CH1:SW,CH2:VO,CH4:ISW)

AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 5 - 7. η vs. IO BLOCK DIAGRAM

AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 6 - DETAILED INFORMATION Setting the Output Voltage The internal reference VREF is 1.23V (Typical).The output voltage is divided by a resistor divider, R2 and R1 to the FB pin. The output voltage is given by  += R1 R21 x 1.23VV OUT Power Sequence In order to assure the normal soft start function for suppressing the inrush current the input voltage should be ready before EN pulls high. Soft-Start The function of soft-start is made for suppressing the inrush current to an acceptable value at the beginning of power-on. The A8176 provides a built-in soft-start function by clamping the output voltage of error amplifier so that the duty cycle of the PWM will be increased gradually in the soft-start period. Current Limiting The current flow through inductor as charging period is detected by a current sensing circuit. As the value comes across the current limiting threshold, the N -MOSFET will be turned off so that the inductor will be forced to leave charging stage and enter discharging stage. Therefore, the inductor current will not increase over the current limiting threshold. Capacitor Selection Input ceramic capacitor of 10uF and output ceramic capacitor of 10uF are recommended for the A8176 applications. For better voltage filtering, ceramic capacitors with low ESR are recommended. X5R and X7R types are suitable because of their wider voltage and temperature ranges. Inductor Selection The recommended value of inductor are 4.7 to 22μH. Small size and better efficiency are the major concerns for portable device. Small size and better efficiency are the major concerns for portable devices, such as the A8176 used for mobile phone. The inductor should have low core loss at 1.0MHz and low DCR for better efficiency. The inductor saturation current rating should be considered to cover the inductor peak current.

AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 7 - Diode Selection Schottky diode is a good choice for A8176 because of its low forward voltage drop and fast reverse recovery. Using Schottky diode can get better efficiency. The high speed rectification is also a good characteristic of Schottky diode for high switching frequency. Current rating of the diode must meet the root mean square of the peak current and output average current multiplication as following: (RMS)ID ≈ PEAKOUTxII The diode’ s reverse breakdown voltage should be larger than the output voltage. Layout Consideration For best performance of the A8176, the following guidelines must be strictly followed.  Input and Output capacitors should be placed close to the IC and connected to ground plane to reduce noise coupling.  The GND and Exposed Pad should be connected to a strong ground plane for heat sinking and noise protection.  Keep the main current traces as possible as short and wide.  SW node of DC-DC converter is with high frequency voltage swing. It should be kept at a small area.  Place the feedback components as close as possible to the IC and keep away from the noisy devices. TYPICAL APPLICATION CIRCUITS Figure 2 LCD Display Power

AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 8 -

PACKAGE INFORMATION

Dimension in SOT-25 (Unit: mm) Symbol Millimeters Inches Min Max Min Max A 1.050 1.250 0.041 0.049 A1 0.000 0.100 0.000 0.004 A2 1.050 1.150 0.041 0.045 b 0.300 0.500 0.012 0.020 c 0.100 0.200 0.004 0.008 D 2.820 3.020 0.111 0.119 E 1.500 1.700 0.059 0.067 E1 2.650 2.950 0.104 0.116 e 0.950(BSC) 0.037(BSC) e1 1.800 2.000 0.071 0.079 L 0.300 0.600 0.012 0.024 θ 0° 8° 0° 8°

AiT Semiconductor Inc. www.ait-ic.com A8176 LED DRIVER 1.0MHz, 1.2A UP TO 2 4V OUTPUT MICROPOWER REV1.1 - JUL 2013 RELEASED, MAY 2017 UPDATED - - 9 - 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. Use of AiT products in such applications is understood to be fully at the risk of the customer. As used herein may involve potential risks of death, personal injury, or server 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.