ETA1476FT2G

ETA1476 28V, 2A, High Efficiency Synchronous Step-Down Converter in FCTSOT23-6 DESCRIPTION FEATURES ETA1476 is a wide input range, high-efficiency and high  Wide Input Range: 4.5V-28V frequency DC-to-DC step-down switching regulator, capable of  High Efficiency PFM mode at light load delivering up to 2A of output current. With a fixed switching  Capable of Delivering 2A frequency of 500KHz, this current mode PWM controlled  No External Compensation Needed converter allows the use of small external components, such as  Current Mode Control ceramic input and output caps, as well as small inductors.  Thermal Shutdown and UVLO ETA1476 also employs a proprietary control scheme that  Excellent Load and Line Transient Response switches the device into a power save mode during light load,  Available in FCTSOT23-6 Package thereby extending the range of high efficiency operation. The IC can stand off input voltage as high as 30V against input voltage surges, making it an ideal solution for industrial applications such as LCD TV, Set Top Box, Portable TV, etc. APPLICATIONS    ETA1476 is available in FCTSOT23-6 package. LCD TV Set Top Box Portable TV TYPICAL APPLICATION ORDERING INFORMATION www.etasolution.com PART No. PACKAGE TOP MARK Pcs/Reel ETA1476FT2G FCTSOT23-6 CxYW 3000 1 Powering Minds of the Smart ETA1476 PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS (Note: Exceeding these limits may damage the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability.) IN,SW,EN Voltage ..............................................................–0.3V to 30V BST Voltage .................................................................–0.3V to SW+6V FB Voltage ............................................................................–0.3V to 6V Operating Temperature Range ……………….....….……–40C to 85C Storage Temperature Range …………………….……….–55C to 150C Thermal Resistance JA JC FCTSOT23-6………………….……………...….…..….100…....….55…...... C/W Lead Temperature (Soldering 10ssec) ……….…………………….260C ESD HBM (Human Body Mode) ……………………………………………….2KV ESD MM (Machine Mode) …………………………………………....……..….200V FCTSOT23-6 ELECTRICAL CHACRACTERISTICS (VIN = 12V, VOUT = 3.3V, unless otherwise specified. Typical values are at TA = 25C.) PARAMETER Input Voltage Range Input UVLO Input Supply Current Input Shutdown Current FB Voltage FB Input Current Switching Frequency Maximum Duty Cycle Short Circuit Hiccup Time FB Hiccup Threshold High Side Switch On Resistance Low Side Switch On Resistance High Side Current Limit SW Leakage Current EN Rising Threshold EN Falling Threshold EN Input Current Thermal Shutdown www.etasolution.com CONDITIONS Rising, Hysteresis=340mV VFB=0.65V MIN 4.5 4.0 0.585 91 On Time Off Time 3 TYP 4.24 640 7 0.6 0 500 93 2 6 0.2 155 88 3.8 IN=SW=12V -6% -6% VEN=2V 1.58 1.40 2 Rising, Hysteresis =40°C 150 2 MAX UNIT 28 4.50 1050 14 0.615 1 V V µA µA V µA kHz % mS mS V mΩ mΩ A µA V V uA 20 +6% -6% 6 °C Powering Minds of the Smart ETA1476 PIN DESCRIPTION PIN # 1 2 3 4 5 6 NAME GND SW VIN FB EN BST DESCRIPTION Ground Inductor Connection. Connect an inductor Between SW and the regulator output. Supply Voltage. Bypass with a 22μF ceramic capacitor to GND Feedback Input. Connect an external resistor divider from the output to FB and GND to set VOUT Enable pin for the IC. Drive this pin high to enable the part, low or floating to disable. Bootstrap pin. Connect a 10nF capacitor from this pin to SW TYPICAL CHARACTERISTICS (Typical values are at TA = 25C unless otherwise specified.) Switching Waveform at Iout = 0A (Vin=12V, Vout=3.3V) Switching Waveform at Iout = 2A (Vin=12V, Vout=3.3V) Vout Vout Isw Isw SW SW www.etasolution.com 3 Powering Minds of the Smart ETA1476 Load Transient Response –Iout Rising Edge 1A/1us Vin=12V, Vout=1.1V, L=2.2uH, Cout=22uFx2, Iout 0.3-1.5A Vout Load Transient Response – Iout Falling Edge 1A/0.2us Vin=12V, Vout=1.1V, L=2.2uH, Cout=22uFx2, Iout 1.5-0.3A Vout Iout FUNCTIONAL BLOCK DIAGRAM FUNCTIONAL DESCRIPTION The ETA1476 is a synchronous buck regulator ICs that integrates the PWM control, top and bottom switches on the same die to minimize the switching transition loss and conduction l The ETA1476 is a wide input range, high efficiency, DC-to-DC step-down switching regulator, capable of delivering up to 2A of output current, integrated with a 155mΩ high side and 88mΩ low side MOSFET. It uses PWM current-mode control scheme. An error amplifier integrates error between the FB signal and the internal reference voltage. The output of the integrator is then compared to the sum of a current-sense signal and the slope compensation ramp. This operation generates a PWM signal that modulates the duty cycle of the power MOSFET to achieve regulation for output voltage. www.etasolution.com 4 Powering Minds of the Smart ETA1476 Light Load Operation Traditionally, a fixed constant frequency PWM DC-DC regulator always switches even when the output load is small. When energy is shuffling back and forth through the power MOSFET, power is lost due to the finite Rdson of the MOSFET and parasitic capacitances. At light load, this loss is prominent and efficiency is therefore very low. ETA1476 employs a proprietary control scheme that improves efficiency in this situation by enabling then device into a power save mode during light load, thereby extending the range of high efficiency operation. Enable EN is a digital control pin that turns the ETA1476 on and off. Drive EN High to turn on the regulator, drive it Low to turn it off. An internal 1MΩ resistor from EN pin to GND allows EN to float to shut down the chip. Connecting the EN pin through a pull up resistor or shorted EN to IN will automatically turn on the chip whenever plug in IN. Over Current Protection and Hiccup ETA1476 has a cycle-by-cycle over current limit for when the inductor current peak value is over the set current limit threshold. When the output voltage drops until FB falls below UV threshold (0.2V), the ETA1476 will enter hiccup mode. It will turn off the chip immediately for 6mS. After that, it will try to re-starts as normal for 2mS. After 2mS, if FB is still below UV threshold, then the chip enters hiccup mode again. If FB is higher than UV threshold, it will enter the normal mode. Over-Temperature Protection Thermal protection disables the output when the junction temperature rises to approximately 150°C, allowing the device to cool down. When the junction temperature cools to approximately 110°C, the output circuitry is again enabled. Depending on power dissipation, thermal resistance, and ambient temperature, the thermal protection circuit may cycle on and off. This cycling limits regulator dissipation, protecting the device from damage as a result of overheating. APPLICATION INFORMATION External Output Voltage Setting In external Output Voltage Setting Version selected, the ETA1476 regulator is programmed using an external resistor divider. The output voltage is calculated using below equation. VOUT =VREF × (1+ Ru ) Rd Where: VREF =0.6V typically (the internal reference voltage) Resistors Rd has to be between 1kOhm to 20KOhm and thus Ru is calculated by following equation. Ru = ( VOUT -1) ×Rd VREF . www.etasolution.com 5 Powering Minds of the Smart ETA1476 PCB LAYOUT GUIDE For any high voltage buck, it is always crucial to have input capacitor placed as close to the chip’s VIN and GND pin as possible without any via, because the input capacitor is to keep the chip’s real input voltage from dropping too much when large switching current is drawn from the input node. A simple illustration of how to place input capacitor is shown below, and it is highly recommended to strictly follow this guide. Always place input capacitor (Cin) at this place! Cin ETA1476 SW trace goes underneath the IC body! PACKAGE OUTLINE Package: FCTSOT23-6 www.etasolution.com 6 Powering Minds of the Smart