CJ9221T5

JIANGSU CHANGJING ELECTRONICS TECHNOLOGY CO., LTD 2A, 1.5MHz Synchronous Step-Down DC-DC Converter CJ9221  INTRODUCTION: The CJ9221 is a high efficiency, DC to DC step down switching regulator, capable of delivering up to 2A of output current. The input and output range of CJ9221 is from 2.7V to 5.5V and 0.6V to VIN, making it suitable for low voltage power conversion. Running at a fixed frequency of 1.5MHz allows the use of small inductance value and low DCR inductors, thereby achieving higher efficiencies. Other external components, such as ceramic input and output caps, can also be small due to higher switching frequency, while maintaining exceptional low noise output voltages. Internal soft start control circuit reduces inrush current.  PIN CONFIGURATION: www.jscj-elec.com 1 „ FEATURES:  Wide Input Voltage Range: 2.7 ~ 5.5V       up to 2A max Output Current Light Load Operation 1.5MHz Frequency 100% Duty Operation Internal Compensation SOT-23-5L Package „ APPLICATION:     USB ports / Hubs Portable Devices Cellphones Tablet PC  Set Top Boxes „ DEVICE INFORMATION: PART NUMBER PACKAGE CJ9221T5 SOT-23-5L Rev - 1.0 Pin$onfiguration  BLOCK DIAGRAM  PIN CONFIGURATION PIN NUMBER PIN NAME FUNCTION 1 EN Enable pin for the IC. Drive this pin to high to enable the part, low to disable. 2 GND Analog Ground pin 3 SW Inductor Connection. Connect an inductor Between SW and the regulator output. 4 VIN Supply Voltage pin. Bypass with a 10μF ceramic capacitor to GND FB Feedback Input. Connect external resistors divider from the output to FB and GND to set the output to a voltage between 0.6V and VIN 5 www.jscj-elec.com 2 Rev - 1.0 Electrical Characteristics  ABSOLUTE MAXIMUM RATINGS(1) (Unless otherwise specified, TA = 25°C) PARAMETER Input Voltage SYMBOL RATINGS UNITS VIN -0.3~ 6.5 VSS-0.3 ~ VIN V (2) SW(DC) FB Voltage (2) V VSS-0.3 ~ VOUT+6.5 V RθJA 250 °C/W Power Dissipation SOT23-5L PD 400 mW Operating Junction Temperature Range TJ -40~+150 °C Storage Temperature Range Tstg -55~+150 °C Lead Temperature (Soldering, 10 sec) Tsolder 260 °C Human Body Model (HBM) 2000 V Machine Model (MM) 200 V SW(AC, less than 10ns) Voltage(2) Thermal Resistance from Junction to Ambient ESD rating(3) (1) 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 my affect device reliability. (2) All voltages are with respect to network ground terminal. (3) ESD testing is performed according to the respective JESD22 JEDEC standard. The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin.  RECOMMENDED OPERATING CONDITIONS PARAMETER MIN. NOM. MAX. UNITS Supply voltage at VIN -0.3 - 5.5 V Output voltage at VOUT -0.3 - 5.5 Operating free air temperature range, TA -40 - 85 V °C www.jscj-elec.com 3 Rev - 1.0 Electrical Characteristics  ELECTRICAL CHARACTERISTICS CJ9221 (VIN = 5V, TA = 25°C, unless otherwise specified) PARAMETER Input Voltage Range CONDITIONS MIN 2.7 TYP Shutdown Supply Current VEN=0V 0.1 Quiescent Current VFB=0.7V 40 Feedbackk Voltage VIN=2.7 to 5.5V 0.588 0.600 MAX 5.5 1 UNIT V µA µA 0.612 V Feedbackk Current 0.01 μA UVLO Hysteresis 0.15 V UVLO Threshold EN in Pull-Low Resistance 2.5 1100 V kΩ EN in Input Low Voltage 0.4 EN in Input High Voltage V V 1.5 NMOS Switch On Resistance 110 mΩ PMOS Switch On Resistance NMOS Current LLimit Output Discharge Switch On Resistance 90 4 mΩ 60 Ω NMOS Leakage Current VEN=0V 10 VIN=5V, VFB=0.7V Maximum Duty μA % 100 Internal Soft-Start Time A 1 ms MHz Short Switching Frequency 1.5 380 Thermal Shutdown Temperature 160 °C Switching Frequency www.jscj-elec.com 4 kHz Rev - 1.0 Typical Characteristics CJ9221 (VIN =5V, VOUT = 1.2V, L = 2.2µH, TA = 25°C, unless otherwise specified) 100% 3.00% VIN=VEN=5V, VOUT=1.2V 90% 1.00% Efficiency(%) Load Regulation(%) 2.00% VIN=VEN=5V, VOUT=1.2V 95% 0.00% -1.00% 85% 80% 75% 70% 65% 60% -2.00% 55% -3.00% 50% 0 0.5 1 1.5 2 0 500 1000 Load(A) IOUT(A) VIN = 5V, VOUT = 1.2V VIN = 5V, VOUT = 1.2V Fig. 1 Load Regulation Fig. 2 Efficiency 1500 2000 Steady State Waveform CH1: VSW CH2: VOUT CH4: ILOAD VIN = 5V, VOUT = 1.2V,ILOAD=0A VIN = 5V, VOUT = 1.2V,ILOAD=0.01A Fig. 3 Steady State Waveform Fig. 4 Steady State Waveform VIN = 5V, VOUT = 1.2V,ILOAD=0.1A VIN = 5V, VOUT = 1.2V,ILOAD=0.05A Fig. 5 Steady State Waveform www.jscj-elec.com Fig. 6 Steady State Waveform 5 Rev - 1.0 Typical Characteristics VIN = 5V, VOUT = 1.2V,ILOAD=0.2A Fig. 7 Steady State Waveform VIN = 5V, VOUT = 1.2V,ILOAD=0.3A Fig. 8 Steady State Waveform Transient Waveform CH1:VOUT CH4:ILOAD VIN = 5V, VOUT = 1.2V,ILOAD=0.01A to 1.2A Fig. 10Transient Waveform VIN = 5V, VOUT = 1.2V,ILOAD=0.01A to 0.8A Fig. 9Transient Waveform www.jscj-elec.com 6 Rev - 1.0 Electrical Characteristics  FUNCTION DESCRIPTION ● General Description CJ9221 high efficiency switching regulator is a small, simple, DC-to-DC step-down converter capable of delivering up to 1A of output current. The device operates in pulse-width modulation (PWM) at 1.5MHz from 2.7V to 5.5V input voltage and provides an output voltage from 0.6V to VIN, making the IC ideal for on-board post-regulation applications. An internal synchronous rectifier improves efficiency and eliminates the typical Schottky free-wheeling diode. Using the on resistance of the internal high-side MOSFET to sense switching currents eliminates current-sense resistors, further improving efficiency and reducing cost. ● Loop Operation The IC uses a PWM current-mode control scheme. An open-loop comparator compares the integrated voltage-feedback signal against the sum of the amplified current-sense signal and the slope compensation ramp. At each rising edge of the internal clock, the internal high-side MOSFET turns on until the PWM comparator terminates the on cycle. During this on-time, current ramps up through the inductor, sourcing current to the output and storing energy in the inductor. The current mode feedback system regulates the peak inductor current as a function of the output voltage error signal. During the off cycle, the internal high-side P-channel MOSFET turns off, and the internal low-side N-channel MOSFET turns on. The inductor releases the stored energy as its current ramps down. ● Current Sense An internal current-sense amplifier senses the current through the high-side MOSFET during on time and produces a proportional current signal which is used to sum the slope compensation signal. The summed signal then is compared with the error amplifier output by the PWM comparator to terminate the on cycle. ● Current Limit There is a cycle-by-cycle current limit on the high-side MOSFET. When the current flowing out of SW exceeds this limit, the high-side MOSFET turns off and the synchronous rectifier turns on. The IC utilizes a frequency fold-back mode to prevent overheating during short-circuit output conditions. The device enters frequency fold-back mode when the FB voltage drops below 250mV, limiting the current to IPEAK and reducing power dissipation. Normal operation resumes upon removal of the short-circuit condition. ● Soft-Start The IC has an internal soft-start circuit to reduce supply inrush current during startup conditions. When the device exits under-voltage lockout (UVLO), shutdown mode, or restarts following a thermal-overload event, the soft-start circuit slowly ramps up the output voltage. ● UVLO and Thermal Shutdown If VIN drops below 2.5V, the UVLO circuit inhibits switching. Once VIN rises above 2.7V, the UVLO clears, and the soft-start sequence activates. Thermal-overload protection limits total power dissipation in the device. When the junction temperature exceeds TJ= +160°C, a thermal sensor forces the device to shutdown, allowing the die to cool down. The thermal sensor turns the device on again after the junction temperature falls below 60°C. After a thermal-shutdown condition, the soft-start sequence begins. www.jscj-elec.com 7 Rev - 1.0 Typical Application  APPLICATION INFORMATION CJ9221T5 Figure1 Basic Application Circuit : V V 1 R1 R2 ● Setting Output Voltages The resistive voltage divider allows the FB pin to sense a fraction of the output voltage shown as below. For adjustable voltage mode, the output voltage is set by an external resistive voltage divider according to the following equation: R1 VOUT = VFB 1 + R2 where VFB is the feedback reference voltage (0.6V typ.). www.jscj-elec.com 8 Rev - 1.0 Typical Application ● Inductor Selection The peak-to-peak ripple is set to 30% of the output current. This places the peak current far enough from the minimum over current trip level to ensure reliable operation while providing enough current ripples for the current mode converter to operate stably. The inductance is determined as the following equation: VIN − VOUT × D L≥ ∆IL × fSW Where ΔIL is the inductor peak-to-peak ripple current D is the duty cycle determined by VOUT / VIN fSW is the switching frequency. ● Output Capacitor Selection For most applications a nominal 10μF or 22μF capacitor is suitable. The output capacitor keeps output ripple small and ensures control-loop stability. The output capacitor must also have low impedance at the switching frequency. Ceramic, polymer, and Tantalum capacitors are suitable, with ceramic exhibiting the lowest ESR and high-frequency impedance. Output ripple with a ceramic output capacitor is approximately as follows: VOUT ≤ ∆IL ESR + 1 8fCOUT ● Input Capacitor Selection The input capacitance, CIN, is needed to filter the trapezoidal current at the source of the top MOSFET. To prevent large ripple current, a low ESR input capacitor sized for the maximum RMS current should be used. The RMS current is given by : D×1−D , where I = IOUT / IRMS = IOUT × This formula has a maximum at VIN = 2VOUT www.jscj-elec.com RMS 9 2 Rev - 1.0 SOT-23-5L Package Outline Dimensions Symbol Dimensions In Millimeters Min. Max. Dimensions In Inches 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 2.650 2.950 0.104 0.116 E1 1.500 1.700 0.059 0.067 e 0.037(BSC) 0.950(BSC) e1 1.800 2.000 0.071 0.079 L 0.300 0.600 0.012 0.024 θ 0° 8° 0° 8° SOT-23-5L Suggested Pad Layout Note: 1.Controlling dimemsion in milimeters. 2.General tolerance: ±0.05mm. 3.The pad layout is for reference purpose only. www.jscj-elec.com 10 Rev - 1.0 DISCLAIMER IMPORTANT NOTICE, PLEASE READ CAREFULLY The information in this data sheet is intended to describe the operation and characteristics of our products. JSCJ has the right to make any modification, enhancement, improvement, correction or other changes to any content in this data sheet, including but not limited to specification parameters, circuit design and application information, without prior notice. Any person who purchases or uses JSCJ products for design shall: 1. Select products suitable for circuit application and design; 2. Design, verify and test the rationality of circuit design; 3. Procedures to ensure that the design complies with relevant laws and regulations and the requirements of such laws and regulations. JSCJ makes no warranty or representation as to the accuracy or completeness of the information contained in this data sheet and assumes no responsibility for the application or use of any of the products described in this data sheet. Without the written consent of JSCJ, this product shall not be used in occasions requiring high quality or high reliability, including but not limited to the following occasions: medical equipment, automotive electronics, military facilities and aerospace. JSCJ shall not be responsible for casualties or property losses caused by abnormal use or application of this product. Official Website: www.jscj-elec.com Copyright © JIANGSU CHANGJING ELECTRONICS TECHNOLOGY CO., LTD.