U3500

U3500 DATA SHEET ZHEJIANG UNIU-NE Technology CO.,LTD 浙 江 宇 力 微 新 能 源 科 技 有 限 公 司 U3500 Data Sheet V 3.0 版权归浙江宇力微新能源科技有限公司 www.uni-semic.com 0575-85087896 U3500 DATA SHEET 120V Input, Switching Current Limit Step-Down Converter General Description Key Features The U3500 is a high-voltage, stepdown, switching regulator that drives External power MOSFET with a current limit of 10A, typically. The wide 10V to 120V input range accommodates a variety of step-down applications, making it ideal for automotive, industry, and lighting applications. Hysteretic voltagemode control is employed for very fast response. UNI’s proprietary feedback control scheme minimizes the number of required external components. The switching frequency is 70KHz, allowing for small component size. Thermal shutdown and short-circuit shutdown (SCS) provide reliable and fault-tolerant operations. Low quiescent current allows the U3500 to be used in battery-powered applications. The U3500 is available in a ESOP-8 package with an exposed pad.  Wide 10V to 120V Input Range  DC-DC 12V/10A Typical Switching Current Application  Hysteretic Control: No Compensation  70KHz Switching Frequency  PWM Control Input for step-down Application  Short-Circuit Shutdown (SCS) with Integrated IC  Low Quiescent Current  Thermal Shutdown  Available in a ESOP-8 Package with an Exposed Pad Applications Typical Application  Scooters, E-Bike Control Power Supplies  Solar Energy Systems  Automotive System Power  Industrial Power Supplies  High-Power LED Drivers www.uni-semic.com 1 0575-85087896 U3500 DATA SHEET Ordering Information Part Number Package Vo VIN MAX Load Current U3500 ESOP-8 ＞2V 120V Io＜=10A Pin Description Pin Functions SOP-8 EP SOP-8 EP Pin # Name Description 1 VIN Input supply. VIN supplies power toallofthe internal control circuitries , both BST regulators , and the high -side switch . A decoupling capacitor to ground must be placed close to VIN to minimizeswitchingspikes. 2 EN Enable input. Pull EN below the specified threshold to shut down the U3500. Pull EN above the specified threshold or leave EN floating to enable the U3500. 3 FB Feedback. FB is the input to the voltage hysteretic comparators. The average FB voltage is maintained at 200mV by loop regulation. 4 BS Bootstrap.Connected to a bootstrap diode 1N4148. 5 VB Boot. BST is the positive power supply for the internal, floating, high-side MOSFET driver. Connect a bypass capacitor between BST and SW. 6 SW Switch node. SW is the output,drives External power MOSFET 7 VS Switch source.Upper drive low potential 8 IS Current detection. Current Sensing Input 9 EP-GND Ground. GND should beplaced asclose to the output capacitor aspossible toavoid the highcurrentswitchpaths.ConnecttheexposedpadtoGNDplaneforoptimalthermalperformance. www.uni-semic.com 2 0575-85087896 U3500 DATA SHEET Block Diagram Figure 1:Function Block Diagram Absolute Maximum Ratings (Note 1) Parameter Value Unit -0.3 to 120 V VB Supply Voltage 120+7 V VB Clamp Current 1 mA -0.3 to 7 V Package Thermal Resistance ---Junction to Ambient (ESOP-8) 165 °C/W Maximum Junction Temperature 160 °C -65 to 150 °C 260 °C 3 kV 250 V VIN,SW,VS Pin Voltage Range FB, IS, EN Voltage Range Storage Temperature Range Lead Temperature (Soldering, 10sec.) ESD Capability, HBM (Human Body Model) ESD Capability, MM (Machine Model) www.uni-semic.com 3 0575-85087896 U3500 DATA SHEET Electrical Characteristics VIN=60V, TA = +25°C, unless otherwise noted. Specifications over temperature are guaranteed by design and characterization. Parameter Symbol Condition Min Typ Max Units VIN UVLO threshold — 10.0 — V VIN UVLO hysteresis — 0.4 — V Shutdown supply current VEN = 0V — 1.8 — uA Quiescent supply current No load, DIM =low,VFB=1.25V — 2.2 — mA — 500 — mA — 0.02 1.5 µA Drive source current IS(ON) leakage current ISWLK Working frequency Fsw — 70 80 KHz EN -on VENH — 2.8 7 V EN -off VENL — — 1 V EN threshold hysteresis VENHY — 500 — mV VEN = 0V, VSW = 0V EN input current IENI VEN = 5V — 0.01 1.5 µA EN pull-up current IENS VEN = 2V — 2 3 µA Feedback voltage threshold VFBH 1.22 1.25 1.28 V -800 — 800 nA IFB FB input current FB propagation delay to output (6) high FB propagation delay to output (6) high Thermal shutdown (7) VFB = 5V or 0V TFBDH Falling edge of VFB from 1.25V to 0V to VSW rising edge — 100 — ns TFBDL Rising edge of VFB from 0V to 1.25V to VSW falling edge — 100 — ns Trigger thermal shutdown — 150 — Hysteresis — 20 — ℃ NOTES: Note1:Stresses listed as the above “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 maximum rating conditions for extended periods may remain possibility to affect device reliability. Note2:The device is not guaranteed to function outside its operating conditions. Note3:Guaranteed by design. www.uni-semic.com 4 0575-85087896 U3500 DATA SHEET Typical Characteristics VIN = 60V, TA = +25°C, unless otherwise noted. Shutdown Current vs. Input Voltage Quiesvent Current vs. Input Voltage EN=LOW EN=HIGH,DIM=LOW,VFB=1.25V InputVoltage(V) InputVoltage(V) Shutdown Current vs. Temperature Quiescent Current vs. Temperature Junction Temperature(℃) Junction Temperature(℃) UVLO Threshold vs. Temperature EN Threshold vs. Temperature Junction Temperature(℃) Junction Temperature(℃) VIN=95V, EN=LOW VIN=95V, DIM=LOW,EN=HIGH,VFB=250mV www.uni-semic.com 5 0575-85087896 U3500 DATA SHEET Typical Performance Characteristics VIN = 60V, VOUT = 12V, IOUT = 1A, L = 47μH, COUT = 100μF, TA = +25°C, unless otherwise noted. Efficiency vs. Output Current Load Regulation Output Current(mA) Output Current(mA) Line Regulation Input Voltage(V) www.uni-semic.com 6 0575-85087896 U3500 DATA SHEET Operation Hysteresis Current Control with Adaptive Threshold Adjustment The U3500 operates in a hysteretic voltagecontrol mode to regulate the output voltage. FB is connected to the tap of a resistor divider, which determines the output voltage. The power MOSFET is turned on when the FB voltage (VFB) rises to FBon and remains on until VFB rises to FBoff. The power MOSFET is turned off when VFB drops to FBoff and remains off until VFB falls to FBon. The two thresholds of FBon and FBoff are adjusted adaptively to compensate for all the circuit delays, so the output voltage is regulated with an average 1.25V value at FB. Enable (EN) Control The U3500 has a dedicated enable control pin (EN) with positive logic. Its falling threshold is 2.5V, and its rising threshold is 2.8V . When EN is pulled up to about 3V by an internal current source, so it is enabled. Floating Driver and Bootstrap Charging The floating power MOSFET driver is powered by an external bootstrap capacitor. This floating driver has its own under-voltage lockout (UVLO) protection. The UVLO rising threshold is 10V with a threshold error of 0.2V. The bootstrap capacitor is charged and regulated to about 5V by the dedicated internal bootstrap regulator. If the internal circuit does not have sufficient voltage, and the bootstrap capacitor is not sufficiently charged, extra external circuitry can be used to ensure that the bootstrap voltage is in the normal operating region. Refer to the External Bootstrap Diode section for more details. Under-Voltage Lockout (UVLO) Under-voltage lockout (UVLO) is implemented to protect the chip from operating at an insufficient supply voltage. The UVLO rising threshold is about 10V, while its falling threshold is a consistent 9.5V. Fast charging Function for USB Applications Because the FB reference of the U3500 is very flexible, it is recommended to use the U3500 for USB Fast charging Applications by connecting the current sense resistor between FB and GND. Thermal Shutdown Thermal shutdown is implemented to prevent the chip from operating at exceedingly high temperatures. When the silicon die temperature is higher than its upper threshold, the entire chip shuts down. When the temperature is lower than its lower threshold, the chip is enabled again. Output Short Shutdown Protection The output voltage is well-regulated when VFB is around 1.25V. If the output is pulled Shutdown in over-current protection (OCSP) or is shorted to GND directly, VFB is low, Until the power MOSFET is turned on again. The U3500 regards the low VFB as a failure. The power MOSFET is pulled Shutdown if the failure time is longer . The power MOSFET current is also accurately sensed via a current sense MOSFET. If the current is over the current limit, the IC is is pulled Shutdown. This offers extra protection under output- short conditions. www.uni-semic.com 7 0575-85087896 U3500 DATA SHEET Application Information recommended that the inductor current be continuous in each switching period to prevent reaching the current limit. Calculate the inductor value with Equation (2): Setting the Output Voltage The output voltage (VOUT) is set by a resistor divider (R1 and R2) (see the Typical Application on page 1). To achieve good noise immunity and low power loss, R2 is recommended to be in the range of 1kΩ to 50kΩ. R1 can then be determined with Equation (1): V  VFB R1  OUT  R2 VFB L (VIN  VOUT )  VOUT FSW  I OUT  VIN  K (2) Where K is a coefficient of about 0. 15 ~ 0.85 Output Rectifier Diode The output rectifier diode supplies current to the inductor when the high-side switch is off. To reduce losses due to the diode forward voltage and recovery times, use a Schottky diode. The average current through the diode can be approximated with Equation (3): (1) Where VFB is 1.25V, typically. Output Capacitor and Frequency Setting The output capacitor (COUT) is necessary for achieving a smooth output voltage. The ESR of the capacitor should be sufficiently large compared to the capacitance; otherwise, the system may behave in an unexpected way, and the current ripple may be very high.VFB changes from 1.22V to 1.28V when the power MOSFET switches on. To charge the capacitor and generate 1.28V at FB, the system needs ESR and some inductor current. For example, for a 5V VOUT, if the forward capacitor is 0.1µF, the suggested ESR range of the output capacitor is 100mΩ to 250mΩ. Tantalum or aluminum electrolytic capacitors with a small ceramic capacitor are recommended. A forward capacitor across R1 is recommended when the output capacitor is tantalum or aluminum electrolytic, which can set the desired frequency if the output capacitor and ESR cannot be changed. The forward capacitor can reduce the output voltage ripple. In some application, simply a forward capacitor may not get proper frequency, then we can add a forward resistor in series with the forward capacitor or even more add a ceramic on the output. I D  I OUT  (1  VOUT ) VIN (3) Choose a diode with a maximum reverse voltage rating greater than the maximum input voltage and a current rating is greater than the average diode current. Input Capacitor (CIN) The input current to the step-down converter is discontinuous and therefore requires a capacitor to supply AC current to the step-down converter while maintaining the DC input voltage. Use low ESR capacitors for the best performance, especially under high switching frequency applications. The RMS current through the input capacitor (4): I IN _ AC  I OUT  VOUT V  (1  OUT ) (4) VIN VIN With low ESR capacitors, the input voltage ripple can be estimated with Equation (5): VIN  I OUT  VOUT V  (1  OUT ) (5) FSW  C IN  VIN VIN Choose an input capacitor with enough RMS current rating and enough capacitance for small input voltage ripples. When electrolytic or tantalum capacitors are applied, a small, high-quality ceramic capacitor (i.e.: 0. 1μ F) should be placed as close to the IC as possible. Selecting the Inductor The inductor (L) is required to convert the switching voltage to a smooth current to the load. Although the output current is low, it is www.uni-semic.com 8 0575-85087896 U3500 DATA SHEET External Bootstrap Diode PCB Layout Guidelines An external bootstrap diode may enhance the efficiency of the converter (see Figure 2). An external VB diode is recommended from the BS supply to VB in the following cases:  There is a 5V rail available in the system  IO is greater than 1A This diode is also recommended for high duty cycle operations (when VOUT / VIN > 65%) and very high frequency applications. The bootstrap diode can be a low-cost one, such as FR107. Efficient PCB layout is critical for stable operation. For best results, refer to Figure 3 and follow the guidelines below. 1. Place the input decoupling capacitor, catch diode, and the U3500 (VIN, SW, and PGND) as close to each other as possible. 2. Keep the power traces very short and fairly wide, especially for the SW node. This can help greatly reduce voltage spikes on the SW node and lower the EMI noise level. 3. Run the feedback trace as far from the inductor and noisy power traces (like the SW node) as possible. 4. Place thermal vias with 15mil barrel diameter and 40mil pitch (distance between the centers) under the exposed pad to improve thermal conduction. Figure 2: External Bootstrap Diode www.uni-semic.com 9 0575-85087896 U3500 DATA SHEET Typical Application Circuit APP1: VOUT =12.5V, IOUT = 3A 2 APP2:VOUT =12.5V, IOUT = 10A www.uni-semic.com 10 0575-85087896 U3500 DATA SHEET APP3: , VOUT =12.5V, IOUT =10A(Short-Circuit Shutdown and Off-delay Application) www.uni-semic.com 11 0575-85087896 U3500 DATA SHEET Package Information SOP-8 EP NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating UNI products into any application. UNI will not assume any legal responsibility for any said applications. www.uni-semic.com 12 0575-85087896 U3500 DATA SHEET 1.版本记录 DATE REV. DESCRIPTION 2018/04/ 19 1.0 First Release 2019/05/21 2.0 Package is changed SOP-8 2021/05/21 3.0 Package is changed to ESOP-8 2.免责声明 浙江宇力微新能源科技有限公司保留对本文档的更改和解释权力，不另行通知! 产品不断提升， 以追求高品质、稳定性强、可靠性高、环保、节能、高效为目标，我司将竭诚为客户提供性价 比高的系统开发方案、技术支持等更优秀的服务。量产方案需使用方自行验证并自担所有批量 风险责任。未经我司授权，该文件不得私自复制和修改。 版权所有 浙江宇力微新能源科技有限公司/绍兴宇力半导体有限公司 3.联系我们 浙江宇力微新能源科技有限公司 总部地址：绍兴市越城区斗门街道袍渎路25号中节能科创园45幢4/5楼 电话：0575-85087896（研发部） 传真：0575-88125157 E-mail: htw@uni-semic.com 无锡地址：无锡市新吴区纺城大道299号深港都会广场9-1401 电 话 : 0510-85297939 E-mail: zh@uni-semic.com 深圳地址：深圳市宝安区航城街道三围社区南昌路上合工业园B2栋501 电 话 ：0755-84510976 E-mail: htw@uni-semic.com www.uni-semic.com 13 0575-85087896