ETA2822

ETA2822 36V Input, 3.1A output Step-Down Converter in ESOP-8 DESCRIPTION FEATURES The ETA2822 is a total solution IC specifically for high voltage USB charging applications. It includes a wide input range, highefficiency, and high frequency DC-to-DC step-down switching regulator that is capable of delivering up to 3.1A of output current. The DC-DC in ETA2822 is a current mode converter with a fixed-frequency that is externally adjustable. There is also a cable resistance compensation feature that allows users to adjust the output voltage to compensate for the voltage drop due to cable resistance. An OVP function protects the IC itself and its downstream system against input voltage surges. With this OVP function, the IC can stand off input voltage as high as 42V, making it an ideal solution for industrial applications such as smart powermeters as well as automotive applications. In automotive systems, power comes from the battery, with its voltage typically ranges between 9V and 24V. Including cold crank and double battery jump-starts, the minimum input voltage may be as low as 4V and the maximum up to 36V, This makes ETA2822 ideal for the automotive application. ETA2822 is housed in an ESOP8 package.            Wide Input Operating Range from 4V to 36V Standoff Input Voltage: 42V High Efficiency at 12V In 5V Out: Up to 91%: High Efficiency PFM mode at light load Capable of Delivering 3.1A output current Cable resistance compensation Adjustable Switching frequency Adjustable Output current limit Current Mode control Logic Control Shutdown Thermal shutdown and UVLO APPLICATIONS  Car Charge ports   Smart power-meter system General purpose with high voltage input TYPICAL APPLICATION ORDERING INFORMATION www.etasolution.com PART No. ETA2822E8A 1 PACKAGE ESOP-8 TOP MARK ETA2822 YWW2L Pcs/Reel 4000 Empower Thinkers ETA2822 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.) SW 1 8 EN ROSC 2 7 VIN RCOMP 3 6 BST FB 4 5 ILIM ETA2822 9: GND IN Voltage ...................................................–0.3V to 42V SW, EN Voltage ..................................–0.3V toVIN+0.3V BST Voltage …………………….….…….-0.3V to SW+6V Other Pins Voltage..……………………..….…-0.3V to+6V SW to ground current…………….……...Internally limited Operating Temperature Range …..........…–40°C to 85°C Storage Temperature Range ………...….–55°C to 150°C Thermal Resistance θJA ESOP8……………….…….……….50 .....................°C/W Lead Temperature (Soldering, 10sec) …………….260°C ESD HBM (Human Body Mode) ………….………….2KV ESD MM (Machine Mode) …………………..……….200V ESOP8 ELECTRICAL CHARACTERISTICS (VIN =12V, unless otherwise specified. Typical values are at TA = 25°C.) PARAMETER Input Standoff Voltage Input Voltage Range Input UVLO Input OVP Input Supply Current Input Shutdown Current FB Voltage FB Input Current Switching Frequency FoldBack Frequency Maximum Duty Cycle High side Switch On Resistance High side Switch Current Limit SW Leakage Current Soft-Start Time Short Circuit Hiccup time EN Input Current EN Logic High Voltage EN Logic Low Voltage Thermal Shutdown www.etasolution.com CONDITIONS Rising. Hysteresis=150mV Rising. Hysteresis=1.5V VFB=0.85V. no switching ROSC=200KΩ VFB=0, ROSC=200KΩ fOSC < 600KHz ISW=200mA RILIM=250KΩ VIN=12V,VSW=0, EN= GND IOUT=0A, fOSC =300kHz ON OFF VIN=12V, VEN=5V Rising Falling Rising, Hysteresis=30°C 2 MIN 42 4 0.776 -1 90 0.91 0.81 TYP 3.80 37.5 0.85 6 0.800 0 500 125 100 4 200 0.5 100 0.1 1.05 0.96 150 MAX UNITS V 36 V V V 1 mA μA 0.824 V 1 μA KHz KHz % mΩ A 10 μA μs ms ms 5 μA 1.29 V 0.99 V °C Empower Thinkers ETA2822 PIN DESCRIPTION PIN # 1 NAME SW DESCRIPTION Inductor Connection. Connect an inductor between SW and the regulator output. ROSC Frequency Setting. Connect a resistor from this pin to GND to set the switching frequency. RCOMP Cable Resistance Compensation adjust pin. Connect a resistor from this pin to GND to compensate for voltage drop due to cord resistance FB Feedback Input. Connect an external resistor divider from the output to FB and GND to set VOUT ILIM Current Limit Setting. Connect a resistor from this pin to GND to set the current limit value. BST Bootstrap pin. Connect a 100nF capacitor from this pin to SW VIN Supply Voltage. Bypass with a 10μF ceramic capacitor to GND 2 3 4 5 6 7 8 EN Exposed Pad 9 GND Enable pin for the IC. Drive this pin high to enable the part, low to disable. Ground TYPICAL CHARACTERISTICS (Vin=12V, Vout=5V, TA=250C, unless otherwise specified) Efficiency Vs Iout Vout Vs Iout (Vout set to be 5V) (Vout set to be 5V) 100% 5.02 90% 5 80% 70% Efficiency (%) Vout (V) 4.98 4.96 4.94 Vin=8V 0 0.5 1 1.5 2 2.5 3 Vin=8V Vin=12V Vin=24V 10% 3.5 0% Vin=36V 0.01 0.1 1 10 Iout (A) Iout (A) www.etasolution.com 40% 20% Vin=24V Vin=36V 4.9 50% 30% Vin=12V 4.92 60% 3 Empower Thinkers ETA2822 Output Current limit 6 2500 5 2000 4 Vout (V) Stanby Current (uA) Stanby Current Vs. Input Voltage 3000 1500 1000 3 2 500 1 Vout=5V Ilim=1A Ilim=1.5A Ilim=2A Ilim=2.5A Llim=3A 0 0 5 10 15 20 25 30 35 40 0 0 0.5 1 Input Voltage (V) 1.5 2 2.5 3 3.5 Output Current (A) *Vin=12V, Vout=5V, L=6.8uH, f=300KHz, Rcomp=510Kohm FUNCTIONAL BLOCK DIAGRAM EN BST VIN ILIM UVLO& Thermal shutdown REG & REF RCOMP Current Sense + - + EA FB + COMP network Σ - PWM Logic DRIVER SW OSC ROSC Low Side Discharging Fet Slope Comp GND www.etasolution.com 4 Empower Thinkers ETA2822 APPLICATION INFORMATION Peripheral Capacitor and Inductor Selection Frequency (KHz) 150 300 500 1000 2000 Table 1 .Recommended Peripherals Cin (uF) Cout (uF) L(μH) VOUT (V) 10 10 10 10 10 22x2 22x2 22x2 22x2 22x2 68-100 6.8-22 4.7-10 2.2-4.7 1.0 5 5 5 5 5 Setting the Switching Frequency The ETA2822 uses a constant frequency PWM architecture that can be programmed to switch from 100KHz to 2MHz by using a resistor tied from the ROSC pin to ground. A table showing the necessary ROSC value for a desired switching frequency is below. Table 2. SW Frequency vs ROSC Value ROSC(kΩ) f(KHz) 82 1000 100 880 150 600 220 420 330 300 390 260 470 220 680 160 Cable Resistance compensation Iout 0 0.1 0.5 1 1.5 2 2.5 3 Rcomp=150k (Rcable=100mΩ) 5.195 5.217 5.256 5.3 5.346 5.393 5.44 5.489 www.etasolution.com Rcomp=300k (Rcable=50mΩ) 5.193 5.201 5.221 5.248 5.272 5.297 5.323 5.352 Rcomp=510k (Rcable=30mΩ) 5.188 5.191 5.2 5.216 5.234 5.252 5.271 5.288 5 Vout(V) The ETA2822 has a cable cord resistance compensation feature to compensate the voltage drop due to cord resistance. The amount of added output voltage can be adjusted by an external resistor connected between RCOMP and GND pin. Iout(A) Empower Thinkers ETA2822 Setting of Output Current Limit Given the input voltage, inductor value and oscillation frequency, the output current limit can be set by external resistor connected to RILIM pin. Several typical current limit setting is listed in following table at Vin=12V, f=300KHz and L=6.8uH. Output Current Limit (A) 1 1.5 2 2.5 3.5 RILIM (K) 750 560 430 300 200 Heat Consideration and PCB Guideline ETA2822 can deliver current up to 3.1A, and there will be a large amount of heat generated by the chip even though the efficiency is higher than 90% in most cases. Beside the ETA2822 itself, the 2 Schottky Diode (SBD) also generate a lot of heat. Please draw large heat sink area in PCB for ETA2822 and the 2 SBDs. In addition, 2 oz copper is recommended to be used on the PCB for better heat dissipation. A picture of DEMO PCB is shown below. Please place the input capacitor (Cin1 and Cin2) as close to the chip as possible and placing this input capacitor is always the highest priority in drawing a PCB for ETA2822. www.etasolution.com 6 Empower Thinkers ETA2822 PACKAGE OUTLINE Package: ESOP-8 www.etasolution.com 7 Empower Thinkers