RT5750A RICHTEK | Alldatasheet
Document overview
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Technical content
Features
Input Voltage Range from 2.5V to 6V Integrated 120m and 80m FETs 1A Output Current, up to 95% Efficiency 100% Duty Cycle for Lowest Dropout 1.5% Internal Reference Voltage 1.5MHz Typical Switching Frequency Power Saving Mode for Light Loads (RT5750A) Low Quiescent Current: 25A (Typ.) Fast Advanced Constant On -Time ( ACOT® ) Control Internal Soft Startup (0.6ms) Enable Control Input Power Good Indicator (TSOT-23-6) Both FETs Over-Current Protection Negative Over-Current Protection (RT5750B) Input Under-Voltage Lockout Protection Hiccup-Mode Output Under-Voltage Protection Over-Temperature Protection RoHS Compliant and Halogen Free
Applications
Mobile Phones and Handheld Devices STB, Cable Modem, and xDSL Platforms WLAN ASIC Power / Storage (SSD and HDD) General Purpose for POL LV Buck Converter Simplified Application Circuit EN RT5750A/B FBGND VINVIN CIN *PG L COUT SW VOUT RFB1Enable RFB2 CFF VPG RPG *PG : TSOT-23-6 only.
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020
Ordering Information
J5 : TSOT-23-5 J6 : TSOT-23-6 Lead Plating System G : Green (Halogen Free and Pb Free) UVP Option H : Hiccup PWM Operation Mode A : Automatic PSM B : Forced PWM Note : Richtek products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. Marking Information RT5750AHGJ5 9M= : Product Code DNN : Date Code9M=DNN RT5750AHGJ6 3G= : Product Code DNN : Date Code3G=DNN RT5750BHGJ5 9L= : Product Code DNN : Date Code9L=DNN RT5750BHGJ6 3F= : Product Code DNN : Date Code3F=DNN Pin Configuration (TOP VIEW) EN GND SW FB PG VIN 2 3 TSOT-23-6 EN GND SW FB VIN 2 3 TSOT-23-5
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5750A/B-00 May 2020 www.richtek.com Functional Pin Description Pin No. Pin Name Pin Function TSOT-23-6 TSOT-23-5 1 1 EN Enable control input. Connect this pin to logic high enables the device and connect this pin to GND disables the device. Do not leave this pin floating. 2 2 GND Signal and power ground pin. Place the bottom resistor of the feedback network as close as possible to this pin. 3 3 SW Switch node between the internal switch. Connect this pin to the inductor. 4 4 VIN Power input. The input voltage range is from 2.5V to 6V. Connect input capacitors directly to this pin and GND pins. MLCC with capacitance higher than 10F is recommended. 5 -- PG Power good indicator. The output of this pin is an open -drain with external pull-up resistor. After soft startup, PG is pulled up when the FB voltage is within 90% (typ.). The PG status is low while EN is disable. 6 5 FB Feedback voltage input. Connect this pin to the midpoint of the external feedback resistive divider to set the output voltage of the converter to the desired regulation level. The device regulates the FB voltage at Feedback Reference Voltage, typically 0.6V.
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020 Functional Block Diagram For TSOT-23-6 PG VIN GND EN VREF Shutdown Control SWFB Driver TON Logic Control SW Current Limit Detector Comparator+-+ Error Amplifier UVLO OTP SW - VFB Ramp Generator UV FBVIN 90%VREF SW Discharge Resistor For TSOT-23-5 VIN GND EN VREF Shutdown Control SWFB Driver TON Logic Control SW Current Limit Detector Comparator+-+ Error Amplifier UVLO OTP SW Ramp Generator UV FBVIN SW Discharge Resistor
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. output current from a 2.5V to 6V input supply. enables the use of smaller output capacitance. pseudo-fixed frequency over the input voltage range. is turned off when the zero inductor current is detected. maintain high efficiency at light load. Figure 1. Start-Up Sequence
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. load current, and the efficiency of the design. output (PGOOD) to monitor the output voltage status. pin will be in high impedance and VPG will be held high. good indication profile is shown below. Figure 2. The Logic of PGOOD Table 1. PG Pin Status current or inductor saturation.
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020 Negative Over-Current Limit (RT5750B) The RT5750B is the part which is forced to PWM and allows negative current operation. In case of PWM operation, high negative current may be generated as an external power source which is tied to output terminal unexpectedly. As the risk described above, the internal circuit monitors negative current in each on-time interval of low -side MOSFET and compares it with NOC threshold. Once the negative current exceeds the NOC threshold, the low -side MOSFET is turned off immediately, and then the high -side MOSFET will be turned on to discharge the energy of output inductor. This behavior can keep the valley of negative current at NOC threshold to protect low -side MOSFET. However, the negative current can’t be limited at NOC threshold anymore since minimum off-time is reached.
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5750A/B-00 May 2020 www.richtek.com Absolute Maximum Ratings (Note 1) Power Dissipation, PD @ TA = 25C ESD Ratings ESD Susceptibility (Note 2) Recommended Operating Conditions (Note 3) Thermal Information (Note 4 and Note 5) Thermal Parameter TSOT-23-5 TSOT-23-6 Unit JA Junction-to-ambient thermal resistance (JEDEC standard) 230.6 197.6 C/W JC(Top) Junction-to-case (top) thermal resistance 21.8 18.9 C/W JC(Bottom) Junction-to-case (bottom) thermal resistance 19.7 25 C/W JA(EVB) Junction-to-ambient thermal resistance (specific EVB) 79.1 74 C/W JC(Top) Junction-to-top characterization parameter 7.1 10.7 C/W
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020
Electrical Characteristics
(VIN = 3.6V, TA = 25C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Supply Voltage VIN Supply Input Operating Voltage VIN 2.5 -- 6 V Under-Voltage Lockout Threshold VUVLO VIN rising 2.15 2.3 2.47 V Under-Voltage Lockout Threshold Hysteresis VUVLO -- 300 -- mV Shutdown Current ISHDN VEN = 0V -- 0.3 1 µA Quiescent Current (RT5750A) IQ VEN = 2V, VFB = 0.63V -- 25 35 µA Quiescent Current (RT5750B) -- 300 -- Soft-Start Soft-Start Time tSS 10%VOUT to 90%VOUT -- 0.6 -- ms Enable Voltage Enable Voltage Threshold VEN_H EN high-level input voltage 0.6 0.82 0.95 V VEN_L EN low-level input voltage 0.5 0.76 0.9 Feedback Voltage and Discharge Resistance Feedback Threshold Voltage VFB 591 600 609 mV Feedback Input Current IFB VFB = 0.6V, TA = 25°C 0.1 0 0.1 A Internal MOSFET High-Side On-Resistance RDS(ON)_H -- 120 -- mΩ Low-Side On-Resistance RDS(ON)_L -- 80 -- Current Limit High-Side Switch Current Limit ILIM_H 1.85 2.65 -- A Low-Side Switch Valley Current Limit ILIM_L 1.05 1.55 2.05 Low-Side Switch Negative Valley Current Limit ILIM_NL -- 1.5 -- Switching Frequency Switching Frequency fSW -- 1.5 -- MHz On-Time Timer Control Minimum Off-Time tOFF_MIN -- 80 -- ns Hiccup-Mode Output Under-Voltage Protection UVP Trip Threshold VUVP Hiccup detect -- 50 -- % Thermal Shutdown Thermal Shutdown Threshold TSD -- 150 -- Thermal Shutdown Hysteresis TSD -- 30 --
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5750A/B-00 May 2020 www.richtek.com Parameter Symbol Test Conditions Min Typ Max Unit Power Good Power Good High Threshold VTH_PGLH VFB rising, PGOOD goes high -- 90 -- % Power Good High Hysteresis VTH_PGLH VFB falling, PGOOD goes low -- 5 -- % Power Good Falling Delay Time -- 60 -- s Output Discharge Resistor Output Discharge Resistor -- 150 -- Note 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 in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution is recommended. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. θJA and θJC are measured or simulated at TA = 25C based on the JEDEC 51-7 standard. Note 5. θJA(EVB) and ΨJC(TOP) are measured on a high effective -thermal-conductivity four-layer test board which is in size of 70mm x 50mm; furthermore, all layers with 1 oz. Cu. Thermal resistance/parameter values may vary depending on the PCB material, layout, and test environmental conditions.
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. Table 2. Suggested Component Values Table 3. Recommended External Components
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5750A/B-00 May 2020 www.richtek.com Typical Operating Characteristic Efficiency vs. Output Current 100 0.001 0.01 0.1 1 Output Current (A) Efficiency (%) VOUT = 1.8V VOUT = 1V RT5750A, VIN = 3.6V Efficiency vs. Output Current 100 0.001 0.01 0.1 1 Output Current (A) Efficiency (%) RT5750B, VIN = 3.6V VOUT = 1.8V VOUT = 1V Efficiency vs. Output Current 100 0.001 0.01 0.1 1 Output Current (A) Efficiency (%) VOUT = 3.3V VOUT = 1.8V VOUT = 1V RT5750A, VIN = 5V Efficiency vs. Output Current 100 0.001 0.01 0.1 1 Output Current (A) Efficiency (%) RT5750B, VIN = 5V VOUT = 3.3V VOUT = 1.8V VOUT = 1V Output Voltage vs. Output Current 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 0.001 0.01 0.1 1 Output Current (A) Output Voltage (V) RT5750A, VIN = 5V, VOUT = 1V Output Voltage vs. Output Current 0.990 0.995 1.000 1.005 1.010 1.015 0.001 0.01 0.1 1 Output Current (A) Output Voltage (V) RT5750B, VIN = 5V, VOUT = 1V
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020 Output Voltage vs. Input Voltage 0.97 0.98 0.99 1.00 1.01 1.02 1.03 2.5 3 3.5 4 4.5 5 5.5 6 Input Voltage (V) Output Voltage (V) VOUT = 1V, IOUT = 0.5A Current Limit vs. Temperature 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 -50 -25 0 25 50 75 100 125 Temperature (°C) Current Limit (A) Low-Side MOSFET, VIN = 3.6V Current Limit vs. Temperature 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 -50 -25 0 25 50 75 100 125 Temperature (°C) Current Limit (A) High-Side MOSFET, VIN = 3.6V Switching Frequency vs. Temperature 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 -50 -25 0 25 50 75 100 125 Temperature (°C) Switching Frequency (MHz) 1 VIN = 3.6V, VOUT = 1V, IOUT = 0.5A Shutdown Current vs. Temperature 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 -50 -25 0 25 50 75 100 125 Temperature (°C) Shutdown Current (μA) 1 VIN = 3.6V Quiescent Current vs. Temperature -50 -25 0 25 50 75 100 125 Temperature (°C) Quiescent Current (μA) RT5750A, VIN = 3.6V
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5750A/B-00 May 2020 www.richtek.com Quiescent Current vs. Temperature 100 150 200 250 300 350 400 450 500 -50 -25 0 25 50 75 100 125 Temperature (°C) Quiescentt Current (μA) RT5750B, VIN = 3.6V UVLO Threshold vs. Temperature 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 -50 -25 0 25 50 75 100 125 Temperature (°C) UVLO Threshold (V) Falling Rising Enable Threshold vs. Temperature 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 -50 -25 0 25 50 75 100 125 Temperature (°C) Enable Threshold (V) Rising Falling Reference Voltage vs. Temperature 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 -50 -25 0 25 50 75 100 125 Temperature (°C) Reference Voltage (V) VIN = 3.6V, VOUT = 1V, IOUT = 0.5A VIN = 3.6V, VOUT = 1V, IOUT = 10mA to 0.5A TR = TF = 0.5s, L = 1.5H, COUT = 10F x 1 VOUT (20mV/Div) IOUT (500mA/Div) Time (10s/Div) Load Transient Response VIN = 3.6V, VOUT = 1V, IOUT = 0.5A to 1A TR = TF = 0.5s, L = 1.5H, COUT = 10F x 1 VOUT (20mV/Div) IOUT (500mA/Div) Time (10s/Div) Load Transient Response
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020 VIN = 5V, VOUT = 1V, IOUT = 10mA to 0.5A TR = TF = 0.5s, L = 1.5H, COUT = 10F x 1 VOUT (20mV/Div) IOUT (500mA/Div) Time (10s/Div) Load Transient Response VIN = 5V, VOUT = 1V, IOUT = 0.5A to 1A TR = TF = 0.5s, L = 1.5H, COUT = 10F x 1 VOUT (20mV/Div) IOUT (500mA/Div) Time (10s/Div) Load Transient Response VIN = 3.6V, VOUT = 1V, IOUT = 10mA VOUT (10mV/Div) VSW (4V/Div) Time (5s/Div) Output Ripple Voltage VIN = 3.6V, VOUT = 1V, IOUT = 1A VOUT (10mV/Div) VSW (4V/Div) Time (400ns/Div) Output Ripple Voltage VIN = 5V, VOUT = 1V, IOUT = 10mA VOUT (10mV/Div) VSW (4V/Div) Time (5s/Div) Output Ripple Voltage VIN = 5V, VOUT = 1V, IOUT = 1A VOUT (10mV/Div) VSW (4V/Div) Time (400ns/Div) Output Ripple Voltage
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5750A/B-00 May 2020 www.richtek.com VIN = 3.6V, VOUT = 1V, IOUT = 1AVOUT (500mV/Div VSW (4V/Div) VEN (2V/Div) VPG (1V/Div) Time (500s/Div) Power On from EN VIN = 3.6V, VOUT = 1V, IOUT = 1A VOUT (500mV/Div) VSW (4V/Div) VEN (2V/Div) VPG (1V/Div) Time (10s/Div) Power Off from EN VIN = 3.6V, VOUT = 1V, IOUT = 1AVOUT (500mV/Div) VSW (4V/Div) VIN (2V/Div) VPG (1V/Div) Time (500s/Div) Power On from VIN VIN = 3.6V, VOUT = 1V, IOUT = 1A VOUT (500mV/Div) VSW (4V/Div) VIN (2V/Div) VPG (1V/Div) Time (100s/Div) Power Off from VIN
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020
Application Information
The output stage of a synchronous buck converter is composed of an inductor and capacitor, which stores and delivers energy to the load, and forms a second-order low-pass filter to smooth out the switch node voltage to maintain a regulated output voltage. Inductor Selection The inductor selecti on trade -offs among size, cost, efficiency, and transient response requirements. Generally, three key inductor parameters are specified for operation with the device: inductance value (L), inductor saturation current (I SAT), and DC resistance (DCR). A good compromise between size and loss is to choose the peak-to-peak ripple current equals to 20% to 50% of the IC rated current. The switching frequency, input voltage, output voltage, and selected inductor ripple current determines the inductor value as follows : OUT IN OUT IN SW L V V VL = V f I Once an inductor value is chosen, the ripple current (IL) is calculated to determine the required peak inductor current. OUT IN OUT LL L(PEAK) OUT(MAX) IN SW V V V II = and I = IV f L 2 IL(PEAK) should not exceed the minimum value of IC's upper current limit level. Besides, the current flowing through the inductor is the inductor ripple current plus the output current. During power up, faults or transient load conditions, the inductor current can increase above the calculated peak inductor current level calculated above. In transient conditions, the inductor current can increase up to the switch current limit of the device. For this reason, the most conservative approach is to specify an inductor with a saturation current rating equal to or greater than the switch current limit rather than the peak inductor current. Considering the Typical Application Circuit for 1 V output at 1A and an input voltage of 5 V, using an inductor ripple of 0.35A (35% of the IC rated current ), the calculated inductance value is : 1 5 1L 1.52 μH5 1.5MHz 0.35A For the typical application, a standard inductance value of 1.5H can be selected. L 1 5 1I = = 0.36A (36% of the IC rated current)5 1.5MHz 1.5 μH L(PEAK) 0.36Aand I = 1A + = 1.18A 2 For the 1.5H value, th e inductor's saturation and thermal rating should exceed at least 1.18A. For more conservative, the rating for inductor saturation current must be equal to or greater than switch current limit of the device rather than the inductor peak current. For EMI se nsitive application, choosing shielding type inductor is preferred. Input Capacitor Selection Input capacitance, CIN, is needed to filter the pulsating current at the drain of the high -side power MOSFET. CIN should be sized to do this without causing a large variation in input voltage. The waveform of C IN ripple voltage and ripple current are shown in Figure 5. The peak-to-peak voltage ripple on input capacitor can be estimated as equation below : CIN OUT OUT IN SW Where OUT IN VD = V For ceramic capacitors, the equivalent series resistance (ESR) is very low, the ripple which is caused by ESR can be ignored, and the minimum input capacitance can be estimated as equation below : IN_MIN OUT_MAX CIN_MAX SW D 1 DC I Vf = CIN_MAXWhere mV 100 V
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. Figure 5. CIN Ripple Voltage and Ripple Current applications due to its small, robust and very low ESR. capacitor should be 0402 or 0603 in size. load apply) and soar (overshoot on load release). extremely low ESR and relatively small capacitance.
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. minimum off -times, which is as fast as allowed. step up or down should be taken into consideration. Figure 6. Output Voltage Setting operation begins (typically 0.82V).
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020 Keep the high -current paths short, especially at the ground terminals. This practice is essential for stable, jitter-free operation. The high current path comprising of input capacitor, high -side FET, inductor, and the output capacitor should be as short as possible. This practice is essential for high efficiency. Place the input MLCC capacitors as close to the VIN and GND pins as possible. The major MLCC capacitors should be placed on the same layer as the RT5750A/B. SW node is with high frequency voltage swing and should be kept at small area. Keep analog components away from the SW node to prevent stray capacitive noise pickup. Connect feedback network behind the output capacitors. Place the feedback components next to the FB pin. For better thermal performance, to design a wide and thick plane for GND pin or to add a lot of vias to GND plane. An example of PCB layout guide is shown from Figure 11.
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. shunt the high input current. Figure 11. Layout Guide
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020 Outline Dimension Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 1.000 0.028 0.039 A1 0.000 0.100 0.000 0.004 B 1.397 1.803 0.055 0.071 b 0.300 0.559 0.012 0.022 C 2.591 3.000 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 TSOT-23-5 Surface Mount Package
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5750A/B-00 May 2020 www.richtek.com Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 1.000 0.028 0.039 A1 0.000 0.100 0.000 0.004 B 1.397 1.803 0.055 0.071 b 0.300 0.559 0.012 0.022 C 2.591 3.000 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.838 1.041 0.033 0.041 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 TSOT-23-6 Surface Mount Package
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS5750A/B-00 May 2020 Footprint Information Package Number of Pin Footprint Dimension (mm) Tolerance P1 P2 A B C D M
Copyright © 2020 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS5750A/B-00 May 2020 www.richtek.com Package Number of Pin Footprint Dimension (mm) Tolerance P1 A B C D M Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Custom ers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its su bsidiaries.